Previous Recruits

2023 Cohort

  • 1H-NMR Guided Isolation of Bioactive Compounds from Species of the Genus Piper 

    Author: Ian S Wallace 

    Molecules. 2025 Apr 30;30(9):2020. doi: 10.3390/molecules30092020.

    ABSTRACT

    The discovery of bioactive natural products is often challenged by the complexity of isolating and characterizing active compounds within diverse mixtures. Previously, we introduced a 1H NMR-based weighted gene correlation network analysis (WGCNA) approach to identify spectral features linked to growth inhibitory activity of Piper (Piperaceae) leaf extracts against model plant, fungal, and bacterial organisms. This method enabled us to prioritize specific spectral features linked to bioactivity, offering a targeted approach to natural product discovery. In this study, we validate the predictive capacity of the WGCNA by isolating the compounds responsible for the bioactivity-associated resonances and confirming their antifungal efficacy. Using growth inhibition assays, we verified that the isolated compounds, including three novel antifungal agents, exhibited significant bioactivity. Notably, one of these compounds contains a rare imidazolium heterocyclic motif, marking a new structural class in Piper. These findings substantiate the 1H NMR-based WGCNA as a reliable tool for identifying structural types associated with biological activity, streamlining the process of discovering bioactive natural products in complex extracts.

    PMID:40363825 | PMC:PMC12073215 | DOI:10.3390/molecules30092020

  • 2023 Retreat Agenda

  • 2025 Spring Symposium Save the Date

  • 35th E. S. Luttrell Lecture

  • A Case Study for Visual Detection of a Systemic Disease: Optimizing Identification of Phony Peach Disease Based on Statistical and Machine Learning Models 

    Weiqi Luo

    Phytopathology. 2025 Jun 22. doi: 10.1094/PHYTO-03-25-0093-R. Online ahead of print.

    ABSTRACT

    Phony peach disease (PPD), caused by Xylella fastidiosa subsp. multiplex (Xfm), poses a significant threat to commercial peach orchards in Georgia. Early and accurate detection is essential for effective disease management, yet visual assessment remains the primary approach for diagnosing PPD symptoms due to the high cost and logistical challenges of qPCR-based detection of Xfm. We evaluated the accuracy of visual PPD assessment and examined the factors influencing rater performance, symptom reliability, and optimal survey deployment strategies with CART/Random Forest analyses and simulations. Internode length was the most reliable symptom for PPD identification in two peach cultivars, consistently outperforming other physical traits such as canopy flatness and shape. Primer pair C06Xf-bamA had the greatest relative sensitivity, making it the preferred choice for qPCR confirmation. Principal component analysis suggested that rater experience significantly improved agreement with qPCR results and repeated assessments of the same orchards further enhanced consistency for raters. Simulations results suggested that deploying two experienced raters may provide the highest detection diagnostic accuracy for survey purposes, particularly when qPCR-based pathogen detection is unavailable. Last, PPD-affected trees, through PCR verification and visual identification, exhibited higher mortality rates than Xfm-negative trees, reinforcing the need for early detection and removal to limit disease spread. These findings underscore the importance of strategic rater deployment, targeted symptom selection, and integrating molecular diagnostics when feasible.

    PMID:40544457 | DOI:10.1094/PHYTO-03-25-0093-R

  • A cell-type-specific regulon controlling monoterpene indole alkaloid biosynthesis with feedback and feedforward activation loops 

    Chenxin Li

    New Phytol. 2025 Nov 9. doi: 10.1111/nph.70712. Online ahead of print.

    ABSTRACT

    Monoterpene indole alkaloids (MIA) are a diverse class of plant natural products produced by a subset of lineages within the Asterid clade of eudicots. The diversity of MIAs provides a unique opportunity to study not only the evolution of biosynthetic genes but also their regulation. In this study, we investigate the cell type specificity of biosynthetic genes and coexpressed transcription factors (TFs) in two MIA-producing Asterid species, Catharanthus roseus, a well-studied MIA-producing species, and Camptotheca acuminata, which belongs to an early-diverging lineage of the Asterid clade. We generated single-cell RNA-seq data from the C. acuminata stem, the primary site of camptothecin biosynthesis. We found that MIA biosynthetic genes in C. acuminata are specific to exceptionally rare cell populations. We discovered MYB and bHLH TFs coexpressed in the same cell types as MIA biosynthetic genes in the C. acuminata stem. Interestingly, the C. roseus orthologs of these TFs are idioblast-specific and activate MIA biosynthetic genes in C. roseus upon overexpression. We constructed an extended gene regulatory network for the idioblast metabolic regulon in C. roseus, which contains both feedback and feedforward activation loops. This study demonstrates co-option of the same clades of TFs for regulation of cell-type-specific MIA biosynthesis across two Asterid species separated by c. 115 million years of evolution. Investigating cell-type-specific TFs that are coexpressed with biosynthetic genes across multiple species is a powerful strategy to increase the power for the discovery of plant metabolic regulators.

    PMID:41208325 | DOI:10.1111/nph.70712

  • A compendium of nonredundant short polymerase III promoters for CRISPR applications 

    Michihito Deguchi

    Plant Physiol. 2025 Jul 3;198(3):kiaf294. doi: 10.1093/plphys/kiaf294.

    ABSTRACT

    Minimal native and synthetic Polymerase III promoters enable efficient and customizable CRISPR multiplexing in plants, expanding genome engineering capabilities

    PMID:40673482 | PMC:PMC12268498 | DOI:10.1093/plphys/kiaf294

  • A global dataset of terrestrial biological nitrogen fixation 

    Carla R Reis Ely

    Sci Data. 2025 Aug 5;12(1):1362. doi: 10.1038/s41597-025-05131-4.

    ABSTRACT

    Biological nitrogen fixation (BNF) is the main natural source of new nitrogen inputs in terrestrial ecosystems, supporting terrestrial productivity, carbon uptake, and other Earth system processes. We assembled a comprehensive global dataset of field measurements of BNF in all major N-fixing niches across natural terrestrial biomes derived from the analysis of 376 BNF studies. The dataset comprises 32 variables, including site location, biome type, N-fixing niche, sampling year, quantification method, BNF rate (kg N ha-1 y-1), the percentage of nitrogen derived from the atmosphere (%Ndfa), N fixer or N-fixing substrate abundance, BNF rate per unit of N fixer abundance, and species identity. Overall, the dataset combines 1,207 BNF rates for trees, shrubs, herbs, soil, leaf litter, woody litter, dead wood, mosses, lichens, and biocrusts, 152 herb %Ndfa values, 1,005 measurements of N fixer or N-fixing substrate abundance, and 762 BNF rates per unit of N fixer abundance for a total of 424 species across 66 countries. This dataset facilitates synthesis, meta-analysis, upscaling, and model benchmarking of BNF fluxes at multiple spatial scales.

    PMID:40764484 | DOI:10.1038/s41597-025-05131-4

  • A high-quality genome assembly of the tetraploid Teucrium chamaedrys unveils a recent whole genome duplication and a large biosynthetic gene cluster for diterpenoid metabolism 

    Abigail E Bryson

    Plant Commun. 2025 Jun 3:101393. doi: 10.1016/j.xplc.2025.101393. Online ahead of print.

    ABSTRACT

    Teucrium chamaedrys, also called wall germander, is a small woody shrub native to the Mediterranean region. Its name is derived from the Greek words meaning ‘ground oak’, since its tiny leaves resemble those of an oak tree. Teucrium species are proliferative producers of diterpenes, which afford them valuable properties widely co-opted in traditional and western medicines. Sequence and assembly of the 3 Gbp tetraploid T. chamaedrys revealed 74 diterpene synthase genes, with the vast representation of these diterpene synthases clustered along four genomic loci. Comparative genomics revealed that this cluster is mirrored in the closely related species, Teucrium marum. Along with the presence of several cytochrome p450 sequences, this region is the one of largest biosynthetic gene clusters identified. Teucrium is well known for accumulating clerodane-type diterpenoids which are produced from a kolavanyl diphosphate precursor. To elucidate the complex biosynthetic pathways of these medicinal compounds, we identified and functionally characterized several kolavanyl diphosphate synthases from T. chamaedrys. Its remarkable chemistry and tetraploidy make T. chamaedrys an interesting and unique model for studying genomic evolution and adaptation in plants.

    PMID:40468595 | DOI:10.1016/j.xplc.2025.101393

  • A nitric oxide reductase is a key enzyme target for eliminating fungal emissions of nitrous oxide 

    Blake A Oakley

    Fungal Genet Biol. 2025 Sep 23:104038. doi: 10.1016/j.fgb.2025.104038. Online ahead of print.

    ABSTRACT

    Nitrous oxide (N2O) derived from agricultural activity is a major contributor to Earth’s greenhouse effect. Synthetic nitrogen fertilizer applied at high levels, particularly combined with heavy rainfall events, generates hot spots of N2O emissions in agricultural fields due to the process of microbial denitrification. Here, a key conserved fungal denitrification enzyme necessary for N2O emissions was identified. Phylogenetic analysis revealed that fungal NOR1-like genes, with rare exceptions, are highly conserved and confined to the phylum Ascomycota. Plant pathogenic Fusarium species that possess NOR1 exhibited drastic differences in N2O production based on denitrification potential. Functional characterization of the p450nor nitric oxide reductase encoding gene, NOR1, in the soil-borne denitrifying maize pathogen, Fusarium verticillioides, showed that this enzyme is critical for fungal N2O production. Deletion of the single copy NOR1 gene in F. verticillioides eliminated N2O emissions. Complementation of deletion mutants via the NOR1 gene add-back restored wild type N2O emission levels and segregation analysis further corroborated the pivotal role of NOR1 for N2O emissions. We suggest targeting of the NOR1 enzyme as an effective strategy to reduce fungal-based N2O emissions.

    PMID:40998212 | DOI:10.1016/j.fgb.2025.104038

  • Aerial root formation in Oaxacan maize (Zea mays) landraces persists into the adult phase and is minimally affected by soil nitrogen and ambient humidity 

    Rafael E Venado

    Front Plant Sci. 2025 Jul 11;16:1607733. doi: 10.3389/fpls.2025.1607733. eCollection 2025.

    ABSTRACT

    Maize (Zea mays L.) is the most widely produced crop in the world, and conventional production requires significant amounts of synthetic nitrogen fertilizer, which has negative economic and environmental consequences. Maize landraces from Oaxaca, Mexico, can acquire nitrogen from nitrogen-fixing bacteria that live in a mucilage secreted by aerial nodal roots. The development of these nodal roots is a characteristic traditionally associated with the juvenile vegetative stage of maize plants. However, mature Oaxacan landraces develop many more nodes with aerial roots than commercial maize varieties. Our study shows that Oaxacan landraces develop aerial roots during the juvenile and adult vegetative phases and even during early flowering under greenhouse and field conditions. Surprisingly, the development of these roots was only minimally affected by soil nitrogen and ambient humidity. These findings are an essential first step in developing maize varieties to reduce fertilizer needs in maize production across different environmental conditions.

    PMID:40718026 | PMC:PMC12289584 | DOI:10.3389/fpls.2025.1607733

  • An updated sulfate transporter phylogeny uncovers a perennial-specific subgroup associated with lignification 

    Samantha M Surber

    Tree Physiol. 2025 Jul 11:tpaf080. doi: 10.1093/treephys/tpaf080. Online ahead of print.

    ABSTRACT

    Sulfate-proton co-transporters (SULTRs) mediate sulfate uptake, transport, storage, and assimilation in plants. The SULTR family has historically been classified into four groups (SULTR1-SULTR4), with well-characterized roles for SULTR groups 1, 2, and 4. However, the functions of the large and diverse SULTR3 group remain poorly understood. Here, we present an updated phylogenetic analysis of SULTRs across angiosperms, including multiple early-divergent lineages. Our results suggest that the enigmatic SULTR3 group comprises four distinct subfamilies that predate the emergence of angiosperms, providing a basis for reclassifying the SULTR family into seven subfamilies. This expanded classification is supported by subfamily-specific gene structures and amino acid substitutions in the substrate-binding pocket. Structural modeling identified three serine residues uniquely lining the substrate-binding pocket of SULTR3.4, enabling three hydrogen bonds with the phosphate ion. The data support the proposed neofunctionalization of this subfamily for phosphate allocation within vascular tissues. Transcriptome analysis of Populus tremula × alba revealed divergent tissue expression preferences among SULTR subfamilies and between genome duplicates. We observed partitioned expression in vascular tissues among the four SULTR3 subfamilies, with PtaSULTR3.4a and PtaSULTR3.2a preferentially expressed in primary and secondary xylem, respectively. Gene coexpression analysis revealed coordinated expression of PtaSULTR3.4a with genes involved in phosphate starvation responses and nutrient transport, consistent with a potential role in phosphate homeostasis. In contrast, PtaSULTR3.2a was strongly coexpressed with lignification and one-carbon metabolism genes and their upstream transcription regulators. PtaSULTR3.2a belongs to a eudicot-specific branch of the SULTR3.1 subfamily found only in perennial species, suggesting a specialized role in lignifying tissues. Together, our findings provide a refined phylogenetic framework for the SULTR family and suggest that the expanded SULTR3 subfamilies have undergone neofunctionalization during the evolution of vascular and perennial plants.

    PMID:40643194 | DOI:10.1093/treephys/tpaf080

  • Anionic lipids direct efficient microfluidic encapsulation of stable and functionally active proteins in lipid nanoparticles 

    Suresh Ambati

    Commun Mater. 2025;6(1):34. doi: 10.1038/s43246-025-00749-8. Epub 2025 Feb 22.

    ABSTRACT

    Because proteins do not efficiently pass through the plasma membrane, protein therapeutics are limited to target ligands located at the cell surface or in serum. Lipid nanoparticles can facilitate delivery of polar molecules across a membrane. We hypothesized that because most proteins are amphoteric ionizable polycations, proteins would associate with anionic lipids, enabling microfluidic chip assembly of stable EP-LNPs (Encapsulated Proteins in Lipid NanoParticles). Here, by employing anionic lipids we were able to efficiently load proteins into EP-LNPs at protein:lipid w:w ratios of 1:20. Several proteins with diverse molecular weights and isoelectric points were encapsulated at efficiencies of 70 75%-90% and remained packaged for several months. Proteins packaged in EP-LNPs efficiently entered mammalian cells and fungal cells with cell walls. The proteins delivered intracellularly were functional. EP-LNPs technology should improve cellular delivery of medicinal antibodies, enzymes, peptide antimetabolites, and dominant negative proteins, opening new fields of protein therapeutics.

    PMID:41146908 | PMC:PMC12553553 | DOI:10.1038/s43246-025-00749-8

  • Anne Frances Jarrell wins 1st Place at the NAPB 2023 Poster Competition!

    Anne Frances Jarrell from the 2021 Cohort won first place for the PhD Poster Competition at the 2023 National Association of Plant Breeders meeting!

    In Spring 2022, Anne Frances officially joined the Robin Buell lab as a Graduate Research Assistant. She is interested in using advances in genomics to improve crop breeding, specifically to increase sustainability and crop resiliency in the face of global climate change. Currently, this leads her to work with potatoes and their wild relatives.

    Learn more about Anne Frances and her work by visiting the Buell Lab website!

    Congratulations Anne Frances!

  • Assessing UV-C radiation treatments for dollar spot suppression in seashore paspalum 

    Willis Turner Spratling

    Plant Dis. 2025 Dec 8. doi: 10.1094/PDIS-08-24-1610-RE. Online ahead of print.

    ABSTRACT

    Dollar spot, caused by Clarireedia spp., is one of the most detrimental diseases of turfgrass worldwide, and control strategies usually involve frequent fungicide applications. These treatments are expensive, require special equipment and can contribute to fungicide resistance issues, underscoring the need for alternative management strategies. UV-C radiation has proven effective as a disease management tool in various cropping systems but is still largely unexplored in turfgrass. This study aimed to test the effects of UV-C radiation against dollar spot in seashore paspalum and to evaluate its impact on plant health and performance. In assessing UV-C’s efficacy directly against C. monteithiana, daily radiation treatments ranging from 27.5 J m-2 to 77.0 J m-2 were shown to effectively reduce mycelial growth. Additionally, in vitro UV-C treatment administered in darkness was observed to be more effective in reducing pathogen growth than treatment administered in lighted conditions. In a growth chamber setting, daily 66.0 J m-2 UV-C treatment significantly reduced dollar spot severity in seashore paspalum without causing phytotoxic damage to plant tissues. In field trials, a novel UV-C application system was implemented by modifying a robotic mower to autonomously deliver UV-C radiation to seashore paspalum plots. UV-C treatment in the field significantly reduced dollar spot severity. Moreover, UV-C treatment led to several physiological and performance enhancements, including increased chlorophyll content, shoot density, surface firmness, and green speed. Findings from this study indicate that UV-C radiation may be used as an effective physical control to complement existing dollar spot management practices.

    PMID:41362131 | DOI:10.1094/PDIS-08-24-1610-RE

  • Biology, Ecology, and Management of Prevalent Thrips Species (Thysanoptera: Thripidae) Impacting Blueberry Production in the Southeastern United States 

    Rosan Adhikari

    Insects. 2025 Jun 24;16(7):653. doi: 10.3390/insects16070653.

    ABSTRACT

    Blueberry is a high-value fruit crop in the United States, with Georgia and Florida serving as important early-season production regions. In these areas, several thrips species (Thysanoptera: Thripidae), including Frankliniella tritici (Fitch), Frankliniella bispinosa (Morgan), and Scirtothrips dorsalis (Hood), have emerged as economically significant pests. While F. tritici and F. bispinosa primarily damage floral tissues, S. dorsalis targets young foliage. Their rapid reproduction, high mobility, and broad host range contribute to rapid population buildup and complicate the management programs. Species identification is often difficult due to overlapping morphological features and requires the use of molecular diagnostic tools for accurate identification. Although action thresholds, such as 2-6 F. tritici per flower cluster, are used to guide management decisions, robust economic thresholds based on yield loss remain undeveloped. Integrated pest management (IPM) practices include regular monitoring, cultural control (e.g., pruning, reflective mulch), biological control using Orius insidiosus (Say) and predatory mites, and chemical control. Reduced-risk insecticides like spinetoram and spinosad offer effective suppression while minimizing harm to pollinators and beneficial insects. However, the brief flowering period limits the establishment of biological control agents. Developing species-specific economic thresholds and phenology-based IPM strategies is critical for effective and sustainable thrips management in blueberry cropping systems.

    PMID:40725285 | DOI:10.3390/insects16070653

  • Bordetellae colonization oligosaccharide (b-Cool), a glycan crucial for nasal colonization 

    Yang Su

    Sci Adv. 2025 Sep 5;11(36):eadw7764. doi: 10.1126/sciadv.adw7764. Epub 2025 Sep 3.

    ABSTRACT

    Respiratory tract infections pose considerable global health challenges. Upper airway colonization is pivotal to these infections, including those caused by Bordetella species. We identified an oligosaccharide, bordetellae colonization oligosaccharide (b-Cool), crucial for early nasal colonization of Bordetella bronchiseptica. We characterized the structure of b-Cool by LC-MS and NMR and found that it is prevalent across a diverse range of bordetellae, including Bordetella pertussis, which causes whooping cough in humans. A B. bronchiseptica mutant lacking b-Cool (Δb-Cool) showed significantly delayed and decreased colonization in mouse nasopharynx and nasal epithelia, resulting in decreased transmission. The colonization defect of Δb-Cool was rescued in mucin deficient mice, suggesting that b-Cool may facilitate colonization in the presence of airway mucins.

    PMID:40901963 | DOI:10.1126/sciadv.adw7764

  • Building an expanded bio-based economy through synthetic biology 

    Andrea M Garza Elizondo

    Biotechnol Adv. 2025 Dec 6:108775. doi: 10.1016/j.biotechadv.2025.108775. Online ahead of print.

    ABSTRACT

    The field of synthetic biology is essential to the continued development of a bio-based economy, creating mechanisms to supply carbon needed in the economy by both converting existing end-of-life wastes as well as by creating novel, purpose-grown and sustainable feedstocks. Here, we first discuss the near- and long-term resources available for use as feedstocks for bioconversion as well as the output molecules needed for building the foundation of an expanded bio-based economy. We then outline the organisms and phenotypic traits that are needed for the performance-advantaged chassis organisms of the future. Furthermore, we detail the advances, challenges, and opportunities in both microbial and plant synthetic biology relevant to expanding the bio-based economy. Finally, we explore technologies that have and will further enable advances in synthetic biology and the greater bio-based economy.

    PMID:41360191 | DOI:10.1016/j.biotechadv.2025.108775

  • Building genomic resources to facilitate the study and use of Solanum microdontum, a wild relative of cultivated potato 

    Anne Frances Jarrell

    G3 (Bethesda). 2025 Oct 23:jkaf253. doi: 10.1093/g3journal/jkaf253. Online ahead of print.

    ABSTRACT

    Solanum microdontum Bitter is a diploid wild Andean relative of potato that has shaped the domestication and adaptation of modern cultivated potato to diverse environments. Solanum microdontum has the potential to provide a wealth of untapped genetic material for use in addressing current challenges in potato breeding. Here, we report a high-quality 772 Mb reference genome sequence for S. microdontum that is anchored to 12 chromosomes. The resulting genome assembly has 99.0% complete Benchmarking Universal Single Copy Orthologs and an N50 scaffold length of over 57 Mb, indicating a high level of completeness. Annotation of the assembly resulted in the identification of 37,324 protein coding genes and 65% repetitive sequence. A total of 1,187 nucleotide-binding leucine-rich repeat genes were predicted from the assembly, of which 93.1% overlapped an annotated high-confidence gene model. A k-mer based kinship matrix derived from a 107-member S. microdontum diversity panel revealed an underlying population structure that corresponds to geographic proximity. The S. microdontum dataset enhances publicly available potato genome resources by providing breeders with genetic, molecular, and germplasm resources for newly developed diploid potato breeding programs.

    PMID:41128648 | DOI:10.1093/g3journal/jkaf253

  • Candidate genes at the Rmi1 locus for resistance to Meloidogyne incognita in soybean 

    Kelly Goode

    Theor Appl Genet. 2025 Oct 29;138(11):286. doi: 10.1007/s00122-025-05065-w.

    ABSTRACT

    The RKN resistance locus Rmi1 was fine-mapped to two genes on chromosome 10, a glycosyl hydrolase family 9 β-1,4-endoglucanase gene and a type I pectin methylesterase gene. Root-knot nematodes (Meloidogyne spp.) are a serious threat to soybean production in the southeast USA, with yield losses of more than $165 million in 2023. Development and deployment of resistant soybean cultivars is the most effective strategy for managing these nematode pests; however, the identity of the resistance genes and underlying mechanism of resistance remains obscure. An additive resistance gene, Resistance to M. incognita-1 (Rmi1), to the predominant species, was first identified in soybean cultivar Forrest but never mapped to a genomic region. Multiple mapping studies have identified a major quantitative trait locus (QTL) with additive action on chromosome 10. In this study, a population consisting of 170 F2:3 families derived from a cross of Bossier (susceptible) × Forrest (resistant) was initially used to confirm that Rmi1 is in the chromosome 10 QTL. Subsequently, 884 F5:6 recombinant inbred lines (RILs) derived from the same cross were used to fine-map the Rmi1 causal gene(s) to two genes – a β-1,4-endoglucanase (Glyma.10G017000, EG) and a pectin methylesterase/methylesterase inhibitor (Glyma.10G017100, PME1). Both gene candidates have the potential to play a role in the resistance response to M. incognita. Both gene promoters harbor SNPs and indels and the encoded proteins exhibit amino acid polymorphisms, including a premature stop in PME1 of resistant soybeans. Additionally, both genes show a higher expression level in susceptible roots compared to resistant roots in the absence of infection. This suggests that Rmi1 may confer one or more pre-existing differences related to cell wall modification in soybean roots, ultimately leading to a decrease in susceptibility.

    PMID:41160124 | DOI:10.1007/s00122-025-05065-w

  • Celebrating the fifth edition of the International Symposium on Fungal Stress – ISFUS, a decade after its 2014 debut 

    Alene Alder-Rangel

    Fungal Biol. 2025 Aug;129(5):101590. doi: 10.1016/j.funbio.2025.101590. Epub 2025 May 6.

    ABSTRACT

    The Fifth International Symposium on Fungal Stress (ISFUS) brought together in Brazil many of the leaders in the field of fungal stress responses, from fourteen countries, for four days of outstanding science ranging from basic research to studies with agricultural, medical, industrial, and environmental significance. In addition to the excellent oral and poster presentations, the Symposium organisers ensured that all participants had ample opportunity to engage, socialise, and network to exchange ideas and share research. The conference was enhanced by the world-class venue near Iguazu Falls, probably the greatest natural phenomenon in South America.

    PMID:40707112 | DOI:10.1016/j.funbio.2025.101590

  • Characterization of Pseudomonas alliivorans strains isolated from Georgia, USA: insights into genomic diversity and pathogenicity in onions 

    Mei Zhao

    Appl Environ Microbiol. 2025 Nov 25:e0164325. doi: 10.1128/aem.01643-25. Online ahead of print.

    ABSTRACT

    Pseudomonas alliivorans is an important emerging pathogen affecting numerous crops. The species is closely related to Pseudomonas viridiflava, with which P. alliivorans strains were often misidentified in the past. Here, we investigated the genetic and pathogenic characteristics of P. alliivorans strains isolated primarily from onions and weeds in Georgia, USA, using whole-genome sequencing, comparative genomics, and functional assays. We delineated the core genome and genetic diversity of these isolates, assessed their pathogenicity on onion foliage and red onion scales, and examined the roles of key virulence determinants (Hrp1-type III secretion system [T3SS], rhizobium-T3SS, type II secretion systems [T2SSs], and thiosulfinate [allicin]-tolerance alt cluster). Our results showed that the Hrp1-T3SS is pivotal for pathogenicity in P. alliivorans, whereas the rhizobium-T3SS, T2SSs, and alt cluster do not contribute to symptom development on red onion scales. Notably, the alt cluster confers in vitro thiosulfinate tolerance, supporting bacterial survival against onion-derived antimicrobial compounds. Additionally, homologous recombination in P. alliivorans occurs infrequently (at approximately one-tenth the rate of point mutations) and involves divergent DNA segments. The alt cluster is acquired through horizontal gene transfer, as evidenced by its lower GC content and the presence of adjacent transposases. In summary, our research provides valuable insights into the genetic diversity, evolutionary dynamics, and virulence mechanisms of P. alliivorans strains from Georgia, USA.IMPORTANCEPseudomonas alliivorans is an emerging plant pathogen that threatens onion and other plants of economic importance. This study identifies key traits that help this bacterium cause disease, such as a specific secretion system critical for infecting onions, and a gene cluster that aids bacterial survival in onion tissues. Beyond highlighting weed as a potential inoculum source and supporting better weed management, the findings of this research open avenues for more targeted disease menegement. By unraveling the genetics of this pathogen, we can develop improved ways to detect, prevent, and reduce its impact, protecting crop health and yields.

    PMID:41288358 | DOI:10.1128/aem.01643-25

  • Comparative Analyses of Four Reference Genomes Reveal Exceptional Diversity and Weak Linked Selection in the Yellow Monkeyflower (Mimulus guttatus) Complex 

    John T Lovell

    Mol Ecol Resour. 2025 Jul 22:e70012. doi: 10.1111/1755-0998.70012. Online ahead of print.

    ABSTRACT

    Yellow monkeyflowers (Mimulus guttatus complex, Phrymaceae) are a powerful system for studying ecological adaptation, reproductive variation, and genome evolution. To initiate pan-genomics in this group, we present four chromosome-scale assemblies and annotations of accessions spanning a broad evolutionary spectrum: two from a single M. guttatus population, one from the closely related selfing species M. nasutus, and one from a more divergent species M. tilingii. All assemblies are highly complete and resolve centromeric and repetitive regions. Comparative analyses reveal such extensive structural variation in repeat-rich, gene-poor regions that large portions of the genome are unalignable across accessions. As a result, this Mimulus pan-genome is primarily informative in genic regions, underscoring limitations of resequencing approaches in such polymorphic taxa. We document gene presence-absence, investigate the recombination landscape using high-resolution linkage data, and quantify nucleotide diversity. Surprisingly, pairwise differences at fourfold synonymous sites are exceptionally high-even in regions of very low recombination-reaching ~3.2% within a single M. guttatus population, ~7% within the interfertile M. guttatus species complex (approximately equal to SNP divergence between great apes and Old World monkeys), and ~7.4% between that complex and the reproductively isolated M. tilingii. Genome-wide patterns of nucleotide variation show little evidence of linked selection, and instead suggest that the concentration of genes (and likely selected sites) in high-recombination regions may buffer diversity loss. These assemblies, annotations, and comparative analyses provide a robust genomic foundation for Mimulus research and offer new insights into the interplay of recombination, structural variation, and molecular evolution in highly diverse plant genomes.

    PMID:40693537 | DOI:10.1111/1755-0998.70012

  • Comparative Transcriptomic Analysis of Soybean Recombinant Inbred Lines Differing at the Rmi1 Locus for Resistance to Meloidogyne incognita During Early Stages of Nematode Infection 

    Kelly Goode

    Phytopathology. 2025 Jun 11. doi: 10.1094/PHYTO-04-25-0143-SC. Online ahead of print.

    ABSTRACT

    Root-knot nematodes (Meloidogyne spp.) are a continuing threat to soybean production, with M. incognita being the predominant species. The deployment of Mi-resistant soybean cultivars is a primary management strategy, but the underlying molecular mechanisms contributing to resistance remain unknown. A single, additive gene for resistance to M. incognita, Rmi1, was previously identified in soybean cv. Forrest and associated with the emigration of second-stage juveniles from the roots. To better understand the Rmi1-mediated resistance response, we used Forrest-derived F5 RILs differing for Rmi1 to analyze global changes in gene expression in response to M. incognita infection at 2- and 4-days post inoculation. We identified 1,471 differentially expressed (DE) genes in the compatible interaction and 1,037 DE genes in the incompatible interaction. Forty-five percent of DE genes were DE in both interactions, 42% (856) were unique to the compatible interaction, and 13% (261) were unique to the incompatible interaction. Genes uniquely DE in the incompatible interaction included genes involved in cell wall modification, hormone signaling, endomembrane trafficking, and redox reactions providing new insights into the resistance mechanism mediated by Rmi1 in soybean to root-knot nematodes.

    PMID:40498525 | DOI:10.1094/PHYTO-04-25-0143-SC

  • Conflicting kinesin-14s in a single chromosomal drive haplotype 

    Author: Kelly Dawe

    Genetics. 2025 May 14:iyaf091. doi: 10.1093/genetics/iyaf091. Online ahead of print.

    ABSTRACT

    In maize, there are two meiotic drive systems that target large heterochromatic knobs composed of tandem repeats known as knob180 and TR-1. The first meiotic drive haplotype, Abnormal chromosome 10 (Ab10) confers strong meiotic drive (∼75% transmission as a heterozygote) and encodes two kinesins: KINDR, which associates with knob180 repeats and TRKIN, which associates with TR-1 repeats. Prior data show that meiotic drive is conferred primarily by the KINDR/knob180 system while the TRKIN/TR-1 system seems to have little or no role, making it unclear why Trkin has been maintained in Ab10 haplotypes. The second meiotic drive haplotype, K10L2, confers a low level of meiotic drive (∼51-52%) and only encodes the TRKIN/TR-1 system. Here we used long-read sequencing to assemble the K10L2 haplotype and showed that it has strong homology to an internal portion of the Ab10 haplotype. We also carried out CRISPR mutagenesis to test the role of Trkin on Ab10 and K10L2. The data indicate that the Trkin gene on Ab10 does not improve drive or fitness but instead has a weak deleterious effect when paired with a normal chromosome 10. The deleterious effect is more severe when Ab10 is paired with K10L2: in this context functional Trkin on either chromosome nearly abolishes Ab10 drive. Mathematical modeling based on the empirical data suggest that Trkin is unlikely to persist on Ab10. We conclude that Trkin either confers an advantage to Ab10 in untested circumstances or that it is in the process of being purged from the Ab10 population.

    PMID:40365704 | DOI:10.1093/genetics/iyaf091

  • Correction: Drought adaptation index (DAI) based on BLUP as a selection approach for drought-resilient switchgrass germplasm 

    Shiva Om Makaju

    Front Genet. 2025 Nov 12;16:1731825. doi: 10.3389/fgene.2025.1731825. eCollection 2025.

    ABSTRACT

    [This corrects the article DOI: 10.3389/fgene.2025.1626083.].

    PMID:41311856 | PMC:PMC12648043 | DOI:10.3389/fgene.2025.1731825

  • Cross-resistance in Alternaria brassicicola from naturally infested broccoli seeds against two succinate dehydrogenase inhibitor fungicides 

    Navjot Kaur

    Appl Environ Microbiol. 2025 Sep 4:e0108325. doi: 10.1128/aem.01083-25. Online ahead of print.

    ABSTRACT

    Seeds can serve as a vehicle for the dissemination of pests and pathogens around the world. We recently demonstrated the association of pathogenic Alternaria brassicicola isolates with reduced sensitivity to azoxystrobin (quinone-outside inhibitor [QoI]) in naturally infested commercial broccoli seeds. In this study, we further demonstrate that these isolates were also resistant to two succinate dehydrogenase inhibitor (SDHI) fungicides. Sensitivity of representative A. brassicicola isolates (n = 58) from naturally infested broccoli seedlots to QoI and SDHI fungicides was evaluated under in vitro conditions. Interestingly, 15% (n = 9/58) of the A. brassicicola isolates with reduced sensitivity to azoxystrobin also displayed reduced sensitivity to two commonly used SDHI fungicides (boscalid and penthiopyrad) in broccoli, indicating a potential case of cross-resistance to SDHI fungicides. Ninety-three percent of the isolates (n = 54/58) were resistant to both boscalid and penthiopyrad, while 100% isolates displayed sensitivity to fluopyram. Sequence analysis of sdh genes revealed the presence of only one point mutation (H134R) in the sdhC gene in isolates that displayed resistance to boscalid and penthiopyrad. We also developed and validated allele-specific primers targeting the H134R mutation for rapid screening of SDHI resistance in A. brassicicola. We also found that boscalid-resistant isolates exhibited significantly reduced mycelial growth. However, spore germination rates among different resistant isolates were not different, suggesting that resistant isolates remain competitive in natural populations. Overall, this study provides the first evidence of fungicide resistance to SDHI fungicides in A. brassicicola isolated from naturally infested broccoli seeds and underscores the importance of seeds as a potential source for introducing fungicide resistance across geographical locations.

    IMPORTANCE: Alternaria brassicicola is a fungal seed-borne pathogen that can be disseminated via commercial seeds across transplant houses and commercial broccoli fields. Our study provides the first evidence that commercial broccoli seeds can harbor pathogenic A. brassicicola isolates with cross-resistance to two succinate dehydrogenase inhibitor (SDHI) fungicides. We observed that 93% of the A. brassicicola isolates from naturally infested commercial broccoli seeds contained a point mutation that conferred resistance to two SDHI fungicides (boscalid and penthiopyrad). Furthermore, we developed a PCR-based allele-specific assay for the rapid detection and monitoring of fungicide resistance. Our study highlights the importance of seed health testing and potential dissemination of fungicide-resistant isolates locally and globally, thus impacting disease management strategies.

    PMID:40905662 | DOI:10.1128/aem.01083-25

  • Deciphering the Biochemical Functions and Nucleotide Sugar Donor Specificity Determinants of Dicot GT61 Glycosyltransferases Involved in Xylan Substitutions 

    Ruiqin Zhong

    Plant Cell Physiol. 2025 Sep 26:pcaf122. doi: 10.1093/pcp/pcaf122. Online ahead of print.

    ABSTRACT

    Plant cell wall polysaccharide glycosyltransferases catalyze the transfer of sugars from specific nucleotide sugar donors onto specific acceptor substrates. The mechanisms of how their enzymatic specificity is determined is one of the long-standing questions in plant cell wall biology. In this report, we studied the biochemical functions of Arabidopsis and poplar GT61 glycosyltransferases involved in xylan substitutions and investigated the molecular determinants of their nucleotide sugar donor specificity. Enzymatic activity assays of recombinant proteins of Arabidopsis and poplar GT61 members demonstrated that two of them, AtX2AT1 and PtrX2AT1, exhibited xylan 2-O-arabinosyltransferase activities specifically using UDP-Araf, two other ones, AtXYXT2/3, possessed xylan 2-O-xylosyltransferase activities specifically using UDP-Xyl, and three other ones, PtrXXAT1/2/3, were able to catalyze the transfer of 2-O-Araf and 2-O-Xyl onto xylan using both UDP-Araf and UDP-Xyl. Structural modeling and molecular docking of PtrXXAT1 identified amino acid residues involved in interacting with UDP-Araf and UDP-Xyl at the putative active site and site-directed mutagenesis revealed their critical roles in PtrXXAT1 catalytic activities. Furthermore, structural alignment and reciprocal swapping of UDP-Xyl-interacting residues of PtrXXAT1 with their corresponding residues of AtX2AT1 pinpointed key residues determining their nucleotide sugar donor specificity. Our results indicate that Arabidopsis and poplar GT61 members catalyze 2-O-Araf- and/or 2-O-Xyl substitutions of xylan and that subtle structural differences in their substrate-binding pockets could alter their substrate specificity toward nucleotide sugar donors.

    PMID:41001967 | DOI:10.1093/pcp/pcaf122

  • Design of genus-specific semi-nested primers for simple and accurate identification of Enterobacter strains 

    Sara Jordan

    BMC Microbiol. 2025 Jul 28;25(1):456. doi: 10.1186/s12866-025-04175-1.

    ABSTRACT

    BACKGROUND: The genus Enterobacter, in the family Enterobacteriaceae, is of both clinical and environmental importance. This genus has undergone frequent taxonomic changes, making it challenging to identify taxa even at genus level. This study aimed to design Enterobacter genus-specific primers that can be used for simple PCR identification of large sets of putative Enterobacter isolates.

    RESULTS: Comparative genomic approaches were employed to identify genes that were universally present on Enterobacter genomes but absent from the genomes of other members of the family Enterobacteriaceae, based on an initial set of 89 genomes. The presence of these genes was further confirmed in 4,276 Enterobacter RefSeq genomes. While no strictly genus-specific genes were identified, the hpaB gene demonstrated a restricted distribution outside of the genus Enterobacter. Semi-nested primers were designed for hpaB and its flanking gene hpaC (hpaBC) and evaluated on 123 strains in single-tube PCR reactions. All taxa showing positive reactions belonged to the genus Enterobacter. For Enterobacter strains the PCR yielded two amplicons at 110 bp and at 370 bp, while strains only displaying the 110 bp amplicon were classified as Leclercia pneumoniae. A blind-test on 120 strains accessioned as Enterobacter sp. from the USDA-ARS culture collection (NRRL), revealed that one third of the strains had an incorrect genus assignment. Comparison of gene trees of the hpaBC fragment sequences with marker genes frequently used for single-gene barcoding or multi-locus sequence analysis (MLSA) further demonstrated its potential for preliminary species identification.

    CONCLUSIONS: The nested PCR assay represents a rapid and cost-effective approach for preliminary identification of Enterobacter species. As the primer design was based on large-scale genomic comparison, including currently undescribed species clades, it will remain valid even after taxonomic changes within the genus.

    PMID:40722002 | DOI:10.1186/s12866-025-04175-1

Previous Recruits

2022 Cohort

  • 1H-NMR Guided Isolation of Bioactive Compounds from Species of the Genus Piper 

    Author: Ian S Wallace 

    Molecules. 2025 Apr 30;30(9):2020. doi: 10.3390/molecules30092020.

    ABSTRACT

    The discovery of bioactive natural products is often challenged by the complexity of isolating and characterizing active compounds within diverse mixtures. Previously, we introduced a 1H NMR-based weighted gene correlation network analysis (WGCNA) approach to identify spectral features linked to growth inhibitory activity of Piper (Piperaceae) leaf extracts against model plant, fungal, and bacterial organisms. This method enabled us to prioritize specific spectral features linked to bioactivity, offering a targeted approach to natural product discovery. In this study, we validate the predictive capacity of the WGCNA by isolating the compounds responsible for the bioactivity-associated resonances and confirming their antifungal efficacy. Using growth inhibition assays, we verified that the isolated compounds, including three novel antifungal agents, exhibited significant bioactivity. Notably, one of these compounds contains a rare imidazolium heterocyclic motif, marking a new structural class in Piper. These findings substantiate the 1H NMR-based WGCNA as a reliable tool for identifying structural types associated with biological activity, streamlining the process of discovering bioactive natural products in complex extracts.

    PMID:40363825 | PMC:PMC12073215 | DOI:10.3390/molecules30092020

  • 2023 Retreat Agenda

  • 2025 Spring Symposium Save the Date

  • 35th E. S. Luttrell Lecture

  • A Case Study for Visual Detection of a Systemic Disease: Optimizing Identification of Phony Peach Disease Based on Statistical and Machine Learning Models 

    Weiqi Luo

    Phytopathology. 2025 Jun 22. doi: 10.1094/PHYTO-03-25-0093-R. Online ahead of print.

    ABSTRACT

    Phony peach disease (PPD), caused by Xylella fastidiosa subsp. multiplex (Xfm), poses a significant threat to commercial peach orchards in Georgia. Early and accurate detection is essential for effective disease management, yet visual assessment remains the primary approach for diagnosing PPD symptoms due to the high cost and logistical challenges of qPCR-based detection of Xfm. We evaluated the accuracy of visual PPD assessment and examined the factors influencing rater performance, symptom reliability, and optimal survey deployment strategies with CART/Random Forest analyses and simulations. Internode length was the most reliable symptom for PPD identification in two peach cultivars, consistently outperforming other physical traits such as canopy flatness and shape. Primer pair C06Xf-bamA had the greatest relative sensitivity, making it the preferred choice for qPCR confirmation. Principal component analysis suggested that rater experience significantly improved agreement with qPCR results and repeated assessments of the same orchards further enhanced consistency for raters. Simulations results suggested that deploying two experienced raters may provide the highest detection diagnostic accuracy for survey purposes, particularly when qPCR-based pathogen detection is unavailable. Last, PPD-affected trees, through PCR verification and visual identification, exhibited higher mortality rates than Xfm-negative trees, reinforcing the need for early detection and removal to limit disease spread. These findings underscore the importance of strategic rater deployment, targeted symptom selection, and integrating molecular diagnostics when feasible.

    PMID:40544457 | DOI:10.1094/PHYTO-03-25-0093-R

  • A cell-type-specific regulon controlling monoterpene indole alkaloid biosynthesis with feedback and feedforward activation loops 

    Chenxin Li

    New Phytol. 2025 Nov 9. doi: 10.1111/nph.70712. Online ahead of print.

    ABSTRACT

    Monoterpene indole alkaloids (MIA) are a diverse class of plant natural products produced by a subset of lineages within the Asterid clade of eudicots. The diversity of MIAs provides a unique opportunity to study not only the evolution of biosynthetic genes but also their regulation. In this study, we investigate the cell type specificity of biosynthetic genes and coexpressed transcription factors (TFs) in two MIA-producing Asterid species, Catharanthus roseus, a well-studied MIA-producing species, and Camptotheca acuminata, which belongs to an early-diverging lineage of the Asterid clade. We generated single-cell RNA-seq data from the C. acuminata stem, the primary site of camptothecin biosynthesis. We found that MIA biosynthetic genes in C. acuminata are specific to exceptionally rare cell populations. We discovered MYB and bHLH TFs coexpressed in the same cell types as MIA biosynthetic genes in the C. acuminata stem. Interestingly, the C. roseus orthologs of these TFs are idioblast-specific and activate MIA biosynthetic genes in C. roseus upon overexpression. We constructed an extended gene regulatory network for the idioblast metabolic regulon in C. roseus, which contains both feedback and feedforward activation loops. This study demonstrates co-option of the same clades of TFs for regulation of cell-type-specific MIA biosynthesis across two Asterid species separated by c. 115 million years of evolution. Investigating cell-type-specific TFs that are coexpressed with biosynthetic genes across multiple species is a powerful strategy to increase the power for the discovery of plant metabolic regulators.

    PMID:41208325 | DOI:10.1111/nph.70712

  • A compendium of nonredundant short polymerase III promoters for CRISPR applications 

    Michihito Deguchi

    Plant Physiol. 2025 Jul 3;198(3):kiaf294. doi: 10.1093/plphys/kiaf294.

    ABSTRACT

    Minimal native and synthetic Polymerase III promoters enable efficient and customizable CRISPR multiplexing in plants, expanding genome engineering capabilities

    PMID:40673482 | PMC:PMC12268498 | DOI:10.1093/plphys/kiaf294

  • A global dataset of terrestrial biological nitrogen fixation 

    Carla R Reis Ely

    Sci Data. 2025 Aug 5;12(1):1362. doi: 10.1038/s41597-025-05131-4.

    ABSTRACT

    Biological nitrogen fixation (BNF) is the main natural source of new nitrogen inputs in terrestrial ecosystems, supporting terrestrial productivity, carbon uptake, and other Earth system processes. We assembled a comprehensive global dataset of field measurements of BNF in all major N-fixing niches across natural terrestrial biomes derived from the analysis of 376 BNF studies. The dataset comprises 32 variables, including site location, biome type, N-fixing niche, sampling year, quantification method, BNF rate (kg N ha-1 y-1), the percentage of nitrogen derived from the atmosphere (%Ndfa), N fixer or N-fixing substrate abundance, BNF rate per unit of N fixer abundance, and species identity. Overall, the dataset combines 1,207 BNF rates for trees, shrubs, herbs, soil, leaf litter, woody litter, dead wood, mosses, lichens, and biocrusts, 152 herb %Ndfa values, 1,005 measurements of N fixer or N-fixing substrate abundance, and 762 BNF rates per unit of N fixer abundance for a total of 424 species across 66 countries. This dataset facilitates synthesis, meta-analysis, upscaling, and model benchmarking of BNF fluxes at multiple spatial scales.

    PMID:40764484 | DOI:10.1038/s41597-025-05131-4

  • A high-quality genome assembly of the tetraploid Teucrium chamaedrys unveils a recent whole genome duplication and a large biosynthetic gene cluster for diterpenoid metabolism 

    Abigail E Bryson

    Plant Commun. 2025 Jun 3:101393. doi: 10.1016/j.xplc.2025.101393. Online ahead of print.

    ABSTRACT

    Teucrium chamaedrys, also called wall germander, is a small woody shrub native to the Mediterranean region. Its name is derived from the Greek words meaning ‘ground oak’, since its tiny leaves resemble those of an oak tree. Teucrium species are proliferative producers of diterpenes, which afford them valuable properties widely co-opted in traditional and western medicines. Sequence and assembly of the 3 Gbp tetraploid T. chamaedrys revealed 74 diterpene synthase genes, with the vast representation of these diterpene synthases clustered along four genomic loci. Comparative genomics revealed that this cluster is mirrored in the closely related species, Teucrium marum. Along with the presence of several cytochrome p450 sequences, this region is the one of largest biosynthetic gene clusters identified. Teucrium is well known for accumulating clerodane-type diterpenoids which are produced from a kolavanyl diphosphate precursor. To elucidate the complex biosynthetic pathways of these medicinal compounds, we identified and functionally characterized several kolavanyl diphosphate synthases from T. chamaedrys. Its remarkable chemistry and tetraploidy make T. chamaedrys an interesting and unique model for studying genomic evolution and adaptation in plants.

    PMID:40468595 | DOI:10.1016/j.xplc.2025.101393

  • A nitric oxide reductase is a key enzyme target for eliminating fungal emissions of nitrous oxide 

    Blake A Oakley

    Fungal Genet Biol. 2025 Sep 23:104038. doi: 10.1016/j.fgb.2025.104038. Online ahead of print.

    ABSTRACT

    Nitrous oxide (N2O) derived from agricultural activity is a major contributor to Earth’s greenhouse effect. Synthetic nitrogen fertilizer applied at high levels, particularly combined with heavy rainfall events, generates hot spots of N2O emissions in agricultural fields due to the process of microbial denitrification. Here, a key conserved fungal denitrification enzyme necessary for N2O emissions was identified. Phylogenetic analysis revealed that fungal NOR1-like genes, with rare exceptions, are highly conserved and confined to the phylum Ascomycota. Plant pathogenic Fusarium species that possess NOR1 exhibited drastic differences in N2O production based on denitrification potential. Functional characterization of the p450nor nitric oxide reductase encoding gene, NOR1, in the soil-borne denitrifying maize pathogen, Fusarium verticillioides, showed that this enzyme is critical for fungal N2O production. Deletion of the single copy NOR1 gene in F. verticillioides eliminated N2O emissions. Complementation of deletion mutants via the NOR1 gene add-back restored wild type N2O emission levels and segregation analysis further corroborated the pivotal role of NOR1 for N2O emissions. We suggest targeting of the NOR1 enzyme as an effective strategy to reduce fungal-based N2O emissions.

    PMID:40998212 | DOI:10.1016/j.fgb.2025.104038

  • Aerial root formation in Oaxacan maize (Zea mays) landraces persists into the adult phase and is minimally affected by soil nitrogen and ambient humidity 

    Rafael E Venado

    Front Plant Sci. 2025 Jul 11;16:1607733. doi: 10.3389/fpls.2025.1607733. eCollection 2025.

    ABSTRACT

    Maize (Zea mays L.) is the most widely produced crop in the world, and conventional production requires significant amounts of synthetic nitrogen fertilizer, which has negative economic and environmental consequences. Maize landraces from Oaxaca, Mexico, can acquire nitrogen from nitrogen-fixing bacteria that live in a mucilage secreted by aerial nodal roots. The development of these nodal roots is a characteristic traditionally associated with the juvenile vegetative stage of maize plants. However, mature Oaxacan landraces develop many more nodes with aerial roots than commercial maize varieties. Our study shows that Oaxacan landraces develop aerial roots during the juvenile and adult vegetative phases and even during early flowering under greenhouse and field conditions. Surprisingly, the development of these roots was only minimally affected by soil nitrogen and ambient humidity. These findings are an essential first step in developing maize varieties to reduce fertilizer needs in maize production across different environmental conditions.

    PMID:40718026 | PMC:PMC12289584 | DOI:10.3389/fpls.2025.1607733

  • An updated sulfate transporter phylogeny uncovers a perennial-specific subgroup associated with lignification 

    Samantha M Surber

    Tree Physiol. 2025 Jul 11:tpaf080. doi: 10.1093/treephys/tpaf080. Online ahead of print.

    ABSTRACT

    Sulfate-proton co-transporters (SULTRs) mediate sulfate uptake, transport, storage, and assimilation in plants. The SULTR family has historically been classified into four groups (SULTR1-SULTR4), with well-characterized roles for SULTR groups 1, 2, and 4. However, the functions of the large and diverse SULTR3 group remain poorly understood. Here, we present an updated phylogenetic analysis of SULTRs across angiosperms, including multiple early-divergent lineages. Our results suggest that the enigmatic SULTR3 group comprises four distinct subfamilies that predate the emergence of angiosperms, providing a basis for reclassifying the SULTR family into seven subfamilies. This expanded classification is supported by subfamily-specific gene structures and amino acid substitutions in the substrate-binding pocket. Structural modeling identified three serine residues uniquely lining the substrate-binding pocket of SULTR3.4, enabling three hydrogen bonds with the phosphate ion. The data support the proposed neofunctionalization of this subfamily for phosphate allocation within vascular tissues. Transcriptome analysis of Populus tremula × alba revealed divergent tissue expression preferences among SULTR subfamilies and between genome duplicates. We observed partitioned expression in vascular tissues among the four SULTR3 subfamilies, with PtaSULTR3.4a and PtaSULTR3.2a preferentially expressed in primary and secondary xylem, respectively. Gene coexpression analysis revealed coordinated expression of PtaSULTR3.4a with genes involved in phosphate starvation responses and nutrient transport, consistent with a potential role in phosphate homeostasis. In contrast, PtaSULTR3.2a was strongly coexpressed with lignification and one-carbon metabolism genes and their upstream transcription regulators. PtaSULTR3.2a belongs to a eudicot-specific branch of the SULTR3.1 subfamily found only in perennial species, suggesting a specialized role in lignifying tissues. Together, our findings provide a refined phylogenetic framework for the SULTR family and suggest that the expanded SULTR3 subfamilies have undergone neofunctionalization during the evolution of vascular and perennial plants.

    PMID:40643194 | DOI:10.1093/treephys/tpaf080

  • Anionic lipids direct efficient microfluidic encapsulation of stable and functionally active proteins in lipid nanoparticles 

    Suresh Ambati

    Commun Mater. 2025;6(1):34. doi: 10.1038/s43246-025-00749-8. Epub 2025 Feb 22.

    ABSTRACT

    Because proteins do not efficiently pass through the plasma membrane, protein therapeutics are limited to target ligands located at the cell surface or in serum. Lipid nanoparticles can facilitate delivery of polar molecules across a membrane. We hypothesized that because most proteins are amphoteric ionizable polycations, proteins would associate with anionic lipids, enabling microfluidic chip assembly of stable EP-LNPs (Encapsulated Proteins in Lipid NanoParticles). Here, by employing anionic lipids we were able to efficiently load proteins into EP-LNPs at protein:lipid w:w ratios of 1:20. Several proteins with diverse molecular weights and isoelectric points were encapsulated at efficiencies of 70 75%-90% and remained packaged for several months. Proteins packaged in EP-LNPs efficiently entered mammalian cells and fungal cells with cell walls. The proteins delivered intracellularly were functional. EP-LNPs technology should improve cellular delivery of medicinal antibodies, enzymes, peptide antimetabolites, and dominant negative proteins, opening new fields of protein therapeutics.

    PMID:41146908 | PMC:PMC12553553 | DOI:10.1038/s43246-025-00749-8

  • Anne Frances Jarrell wins 1st Place at the NAPB 2023 Poster Competition!

    Anne Frances Jarrell from the 2021 Cohort won first place for the PhD Poster Competition at the 2023 National Association of Plant Breeders meeting!

    In Spring 2022, Anne Frances officially joined the Robin Buell lab as a Graduate Research Assistant. She is interested in using advances in genomics to improve crop breeding, specifically to increase sustainability and crop resiliency in the face of global climate change. Currently, this leads her to work with potatoes and their wild relatives.

    Learn more about Anne Frances and her work by visiting the Buell Lab website!

    Congratulations Anne Frances!

  • Assessing UV-C radiation treatments for dollar spot suppression in seashore paspalum 

    Willis Turner Spratling

    Plant Dis. 2025 Dec 8. doi: 10.1094/PDIS-08-24-1610-RE. Online ahead of print.

    ABSTRACT

    Dollar spot, caused by Clarireedia spp., is one of the most detrimental diseases of turfgrass worldwide, and control strategies usually involve frequent fungicide applications. These treatments are expensive, require special equipment and can contribute to fungicide resistance issues, underscoring the need for alternative management strategies. UV-C radiation has proven effective as a disease management tool in various cropping systems but is still largely unexplored in turfgrass. This study aimed to test the effects of UV-C radiation against dollar spot in seashore paspalum and to evaluate its impact on plant health and performance. In assessing UV-C’s efficacy directly against C. monteithiana, daily radiation treatments ranging from 27.5 J m-2 to 77.0 J m-2 were shown to effectively reduce mycelial growth. Additionally, in vitro UV-C treatment administered in darkness was observed to be more effective in reducing pathogen growth than treatment administered in lighted conditions. In a growth chamber setting, daily 66.0 J m-2 UV-C treatment significantly reduced dollar spot severity in seashore paspalum without causing phytotoxic damage to plant tissues. In field trials, a novel UV-C application system was implemented by modifying a robotic mower to autonomously deliver UV-C radiation to seashore paspalum plots. UV-C treatment in the field significantly reduced dollar spot severity. Moreover, UV-C treatment led to several physiological and performance enhancements, including increased chlorophyll content, shoot density, surface firmness, and green speed. Findings from this study indicate that UV-C radiation may be used as an effective physical control to complement existing dollar spot management practices.

    PMID:41362131 | DOI:10.1094/PDIS-08-24-1610-RE

  • Biology, Ecology, and Management of Prevalent Thrips Species (Thysanoptera: Thripidae) Impacting Blueberry Production in the Southeastern United States 

    Rosan Adhikari

    Insects. 2025 Jun 24;16(7):653. doi: 10.3390/insects16070653.

    ABSTRACT

    Blueberry is a high-value fruit crop in the United States, with Georgia and Florida serving as important early-season production regions. In these areas, several thrips species (Thysanoptera: Thripidae), including Frankliniella tritici (Fitch), Frankliniella bispinosa (Morgan), and Scirtothrips dorsalis (Hood), have emerged as economically significant pests. While F. tritici and F. bispinosa primarily damage floral tissues, S. dorsalis targets young foliage. Their rapid reproduction, high mobility, and broad host range contribute to rapid population buildup and complicate the management programs. Species identification is often difficult due to overlapping morphological features and requires the use of molecular diagnostic tools for accurate identification. Although action thresholds, such as 2-6 F. tritici per flower cluster, are used to guide management decisions, robust economic thresholds based on yield loss remain undeveloped. Integrated pest management (IPM) practices include regular monitoring, cultural control (e.g., pruning, reflective mulch), biological control using Orius insidiosus (Say) and predatory mites, and chemical control. Reduced-risk insecticides like spinetoram and spinosad offer effective suppression while minimizing harm to pollinators and beneficial insects. However, the brief flowering period limits the establishment of biological control agents. Developing species-specific economic thresholds and phenology-based IPM strategies is critical for effective and sustainable thrips management in blueberry cropping systems.

    PMID:40725285 | DOI:10.3390/insects16070653

  • Bordetellae colonization oligosaccharide (b-Cool), a glycan crucial for nasal colonization 

    Yang Su

    Sci Adv. 2025 Sep 5;11(36):eadw7764. doi: 10.1126/sciadv.adw7764. Epub 2025 Sep 3.

    ABSTRACT

    Respiratory tract infections pose considerable global health challenges. Upper airway colonization is pivotal to these infections, including those caused by Bordetella species. We identified an oligosaccharide, bordetellae colonization oligosaccharide (b-Cool), crucial for early nasal colonization of Bordetella bronchiseptica. We characterized the structure of b-Cool by LC-MS and NMR and found that it is prevalent across a diverse range of bordetellae, including Bordetella pertussis, which causes whooping cough in humans. A B. bronchiseptica mutant lacking b-Cool (Δb-Cool) showed significantly delayed and decreased colonization in mouse nasopharynx and nasal epithelia, resulting in decreased transmission. The colonization defect of Δb-Cool was rescued in mucin deficient mice, suggesting that b-Cool may facilitate colonization in the presence of airway mucins.

    PMID:40901963 | DOI:10.1126/sciadv.adw7764

  • Building an expanded bio-based economy through synthetic biology 

    Andrea M Garza Elizondo

    Biotechnol Adv. 2025 Dec 6:108775. doi: 10.1016/j.biotechadv.2025.108775. Online ahead of print.

    ABSTRACT

    The field of synthetic biology is essential to the continued development of a bio-based economy, creating mechanisms to supply carbon needed in the economy by both converting existing end-of-life wastes as well as by creating novel, purpose-grown and sustainable feedstocks. Here, we first discuss the near- and long-term resources available for use as feedstocks for bioconversion as well as the output molecules needed for building the foundation of an expanded bio-based economy. We then outline the organisms and phenotypic traits that are needed for the performance-advantaged chassis organisms of the future. Furthermore, we detail the advances, challenges, and opportunities in both microbial and plant synthetic biology relevant to expanding the bio-based economy. Finally, we explore technologies that have and will further enable advances in synthetic biology and the greater bio-based economy.

    PMID:41360191 | DOI:10.1016/j.biotechadv.2025.108775

  • Building genomic resources to facilitate the study and use of Solanum microdontum, a wild relative of cultivated potato 

    Anne Frances Jarrell

    G3 (Bethesda). 2025 Oct 23:jkaf253. doi: 10.1093/g3journal/jkaf253. Online ahead of print.

    ABSTRACT

    Solanum microdontum Bitter is a diploid wild Andean relative of potato that has shaped the domestication and adaptation of modern cultivated potato to diverse environments. Solanum microdontum has the potential to provide a wealth of untapped genetic material for use in addressing current challenges in potato breeding. Here, we report a high-quality 772 Mb reference genome sequence for S. microdontum that is anchored to 12 chromosomes. The resulting genome assembly has 99.0% complete Benchmarking Universal Single Copy Orthologs and an N50 scaffold length of over 57 Mb, indicating a high level of completeness. Annotation of the assembly resulted in the identification of 37,324 protein coding genes and 65% repetitive sequence. A total of 1,187 nucleotide-binding leucine-rich repeat genes were predicted from the assembly, of which 93.1% overlapped an annotated high-confidence gene model. A k-mer based kinship matrix derived from a 107-member S. microdontum diversity panel revealed an underlying population structure that corresponds to geographic proximity. The S. microdontum dataset enhances publicly available potato genome resources by providing breeders with genetic, molecular, and germplasm resources for newly developed diploid potato breeding programs.

    PMID:41128648 | DOI:10.1093/g3journal/jkaf253

  • Candidate genes at the Rmi1 locus for resistance to Meloidogyne incognita in soybean 

    Kelly Goode

    Theor Appl Genet. 2025 Oct 29;138(11):286. doi: 10.1007/s00122-025-05065-w.

    ABSTRACT

    The RKN resistance locus Rmi1 was fine-mapped to two genes on chromosome 10, a glycosyl hydrolase family 9 β-1,4-endoglucanase gene and a type I pectin methylesterase gene. Root-knot nematodes (Meloidogyne spp.) are a serious threat to soybean production in the southeast USA, with yield losses of more than $165 million in 2023. Development and deployment of resistant soybean cultivars is the most effective strategy for managing these nematode pests; however, the identity of the resistance genes and underlying mechanism of resistance remains obscure. An additive resistance gene, Resistance to M. incognita-1 (Rmi1), to the predominant species, was first identified in soybean cultivar Forrest but never mapped to a genomic region. Multiple mapping studies have identified a major quantitative trait locus (QTL) with additive action on chromosome 10. In this study, a population consisting of 170 F2:3 families derived from a cross of Bossier (susceptible) × Forrest (resistant) was initially used to confirm that Rmi1 is in the chromosome 10 QTL. Subsequently, 884 F5:6 recombinant inbred lines (RILs) derived from the same cross were used to fine-map the Rmi1 causal gene(s) to two genes – a β-1,4-endoglucanase (Glyma.10G017000, EG) and a pectin methylesterase/methylesterase inhibitor (Glyma.10G017100, PME1). Both gene candidates have the potential to play a role in the resistance response to M. incognita. Both gene promoters harbor SNPs and indels and the encoded proteins exhibit amino acid polymorphisms, including a premature stop in PME1 of resistant soybeans. Additionally, both genes show a higher expression level in susceptible roots compared to resistant roots in the absence of infection. This suggests that Rmi1 may confer one or more pre-existing differences related to cell wall modification in soybean roots, ultimately leading to a decrease in susceptibility.

    PMID:41160124 | DOI:10.1007/s00122-025-05065-w

  • Celebrating the fifth edition of the International Symposium on Fungal Stress – ISFUS, a decade after its 2014 debut 

    Alene Alder-Rangel

    Fungal Biol. 2025 Aug;129(5):101590. doi: 10.1016/j.funbio.2025.101590. Epub 2025 May 6.

    ABSTRACT

    The Fifth International Symposium on Fungal Stress (ISFUS) brought together in Brazil many of the leaders in the field of fungal stress responses, from fourteen countries, for four days of outstanding science ranging from basic research to studies with agricultural, medical, industrial, and environmental significance. In addition to the excellent oral and poster presentations, the Symposium organisers ensured that all participants had ample opportunity to engage, socialise, and network to exchange ideas and share research. The conference was enhanced by the world-class venue near Iguazu Falls, probably the greatest natural phenomenon in South America.

    PMID:40707112 | DOI:10.1016/j.funbio.2025.101590

  • Characterization of Pseudomonas alliivorans strains isolated from Georgia, USA: insights into genomic diversity and pathogenicity in onions 

    Mei Zhao

    Appl Environ Microbiol. 2025 Nov 25:e0164325. doi: 10.1128/aem.01643-25. Online ahead of print.

    ABSTRACT

    Pseudomonas alliivorans is an important emerging pathogen affecting numerous crops. The species is closely related to Pseudomonas viridiflava, with which P. alliivorans strains were often misidentified in the past. Here, we investigated the genetic and pathogenic characteristics of P. alliivorans strains isolated primarily from onions and weeds in Georgia, USA, using whole-genome sequencing, comparative genomics, and functional assays. We delineated the core genome and genetic diversity of these isolates, assessed their pathogenicity on onion foliage and red onion scales, and examined the roles of key virulence determinants (Hrp1-type III secretion system [T3SS], rhizobium-T3SS, type II secretion systems [T2SSs], and thiosulfinate [allicin]-tolerance alt cluster). Our results showed that the Hrp1-T3SS is pivotal for pathogenicity in P. alliivorans, whereas the rhizobium-T3SS, T2SSs, and alt cluster do not contribute to symptom development on red onion scales. Notably, the alt cluster confers in vitro thiosulfinate tolerance, supporting bacterial survival against onion-derived antimicrobial compounds. Additionally, homologous recombination in P. alliivorans occurs infrequently (at approximately one-tenth the rate of point mutations) and involves divergent DNA segments. The alt cluster is acquired through horizontal gene transfer, as evidenced by its lower GC content and the presence of adjacent transposases. In summary, our research provides valuable insights into the genetic diversity, evolutionary dynamics, and virulence mechanisms of P. alliivorans strains from Georgia, USA.IMPORTANCEPseudomonas alliivorans is an emerging plant pathogen that threatens onion and other plants of economic importance. This study identifies key traits that help this bacterium cause disease, such as a specific secretion system critical for infecting onions, and a gene cluster that aids bacterial survival in onion tissues. Beyond highlighting weed as a potential inoculum source and supporting better weed management, the findings of this research open avenues for more targeted disease menegement. By unraveling the genetics of this pathogen, we can develop improved ways to detect, prevent, and reduce its impact, protecting crop health and yields.

    PMID:41288358 | DOI:10.1128/aem.01643-25

  • Comparative Analyses of Four Reference Genomes Reveal Exceptional Diversity and Weak Linked Selection in the Yellow Monkeyflower (Mimulus guttatus) Complex 

    John T Lovell

    Mol Ecol Resour. 2025 Jul 22:e70012. doi: 10.1111/1755-0998.70012. Online ahead of print.

    ABSTRACT

    Yellow monkeyflowers (Mimulus guttatus complex, Phrymaceae) are a powerful system for studying ecological adaptation, reproductive variation, and genome evolution. To initiate pan-genomics in this group, we present four chromosome-scale assemblies and annotations of accessions spanning a broad evolutionary spectrum: two from a single M. guttatus population, one from the closely related selfing species M. nasutus, and one from a more divergent species M. tilingii. All assemblies are highly complete and resolve centromeric and repetitive regions. Comparative analyses reveal such extensive structural variation in repeat-rich, gene-poor regions that large portions of the genome are unalignable across accessions. As a result, this Mimulus pan-genome is primarily informative in genic regions, underscoring limitations of resequencing approaches in such polymorphic taxa. We document gene presence-absence, investigate the recombination landscape using high-resolution linkage data, and quantify nucleotide diversity. Surprisingly, pairwise differences at fourfold synonymous sites are exceptionally high-even in regions of very low recombination-reaching ~3.2% within a single M. guttatus population, ~7% within the interfertile M. guttatus species complex (approximately equal to SNP divergence between great apes and Old World monkeys), and ~7.4% between that complex and the reproductively isolated M. tilingii. Genome-wide patterns of nucleotide variation show little evidence of linked selection, and instead suggest that the concentration of genes (and likely selected sites) in high-recombination regions may buffer diversity loss. These assemblies, annotations, and comparative analyses provide a robust genomic foundation for Mimulus research and offer new insights into the interplay of recombination, structural variation, and molecular evolution in highly diverse plant genomes.

    PMID:40693537 | DOI:10.1111/1755-0998.70012

  • Comparative Transcriptomic Analysis of Soybean Recombinant Inbred Lines Differing at the Rmi1 Locus for Resistance to Meloidogyne incognita During Early Stages of Nematode Infection 

    Kelly Goode

    Phytopathology. 2025 Jun 11. doi: 10.1094/PHYTO-04-25-0143-SC. Online ahead of print.

    ABSTRACT

    Root-knot nematodes (Meloidogyne spp.) are a continuing threat to soybean production, with M. incognita being the predominant species. The deployment of Mi-resistant soybean cultivars is a primary management strategy, but the underlying molecular mechanisms contributing to resistance remain unknown. A single, additive gene for resistance to M. incognita, Rmi1, was previously identified in soybean cv. Forrest and associated with the emigration of second-stage juveniles from the roots. To better understand the Rmi1-mediated resistance response, we used Forrest-derived F5 RILs differing for Rmi1 to analyze global changes in gene expression in response to M. incognita infection at 2- and 4-days post inoculation. We identified 1,471 differentially expressed (DE) genes in the compatible interaction and 1,037 DE genes in the incompatible interaction. Forty-five percent of DE genes were DE in both interactions, 42% (856) were unique to the compatible interaction, and 13% (261) were unique to the incompatible interaction. Genes uniquely DE in the incompatible interaction included genes involved in cell wall modification, hormone signaling, endomembrane trafficking, and redox reactions providing new insights into the resistance mechanism mediated by Rmi1 in soybean to root-knot nematodes.

    PMID:40498525 | DOI:10.1094/PHYTO-04-25-0143-SC

  • Conflicting kinesin-14s in a single chromosomal drive haplotype 

    Author: Kelly Dawe

    Genetics. 2025 May 14:iyaf091. doi: 10.1093/genetics/iyaf091. Online ahead of print.

    ABSTRACT

    In maize, there are two meiotic drive systems that target large heterochromatic knobs composed of tandem repeats known as knob180 and TR-1. The first meiotic drive haplotype, Abnormal chromosome 10 (Ab10) confers strong meiotic drive (∼75% transmission as a heterozygote) and encodes two kinesins: KINDR, which associates with knob180 repeats and TRKIN, which associates with TR-1 repeats. Prior data show that meiotic drive is conferred primarily by the KINDR/knob180 system while the TRKIN/TR-1 system seems to have little or no role, making it unclear why Trkin has been maintained in Ab10 haplotypes. The second meiotic drive haplotype, K10L2, confers a low level of meiotic drive (∼51-52%) and only encodes the TRKIN/TR-1 system. Here we used long-read sequencing to assemble the K10L2 haplotype and showed that it has strong homology to an internal portion of the Ab10 haplotype. We also carried out CRISPR mutagenesis to test the role of Trkin on Ab10 and K10L2. The data indicate that the Trkin gene on Ab10 does not improve drive or fitness but instead has a weak deleterious effect when paired with a normal chromosome 10. The deleterious effect is more severe when Ab10 is paired with K10L2: in this context functional Trkin on either chromosome nearly abolishes Ab10 drive. Mathematical modeling based on the empirical data suggest that Trkin is unlikely to persist on Ab10. We conclude that Trkin either confers an advantage to Ab10 in untested circumstances or that it is in the process of being purged from the Ab10 population.

    PMID:40365704 | DOI:10.1093/genetics/iyaf091

  • Correction: Drought adaptation index (DAI) based on BLUP as a selection approach for drought-resilient switchgrass germplasm 

    Shiva Om Makaju

    Front Genet. 2025 Nov 12;16:1731825. doi: 10.3389/fgene.2025.1731825. eCollection 2025.

    ABSTRACT

    [This corrects the article DOI: 10.3389/fgene.2025.1626083.].

    PMID:41311856 | PMC:PMC12648043 | DOI:10.3389/fgene.2025.1731825

  • Cross-resistance in Alternaria brassicicola from naturally infested broccoli seeds against two succinate dehydrogenase inhibitor fungicides 

    Navjot Kaur

    Appl Environ Microbiol. 2025 Sep 4:e0108325. doi: 10.1128/aem.01083-25. Online ahead of print.

    ABSTRACT

    Seeds can serve as a vehicle for the dissemination of pests and pathogens around the world. We recently demonstrated the association of pathogenic Alternaria brassicicola isolates with reduced sensitivity to azoxystrobin (quinone-outside inhibitor [QoI]) in naturally infested commercial broccoli seeds. In this study, we further demonstrate that these isolates were also resistant to two succinate dehydrogenase inhibitor (SDHI) fungicides. Sensitivity of representative A. brassicicola isolates (n = 58) from naturally infested broccoli seedlots to QoI and SDHI fungicides was evaluated under in vitro conditions. Interestingly, 15% (n = 9/58) of the A. brassicicola isolates with reduced sensitivity to azoxystrobin also displayed reduced sensitivity to two commonly used SDHI fungicides (boscalid and penthiopyrad) in broccoli, indicating a potential case of cross-resistance to SDHI fungicides. Ninety-three percent of the isolates (n = 54/58) were resistant to both boscalid and penthiopyrad, while 100% isolates displayed sensitivity to fluopyram. Sequence analysis of sdh genes revealed the presence of only one point mutation (H134R) in the sdhC gene in isolates that displayed resistance to boscalid and penthiopyrad. We also developed and validated allele-specific primers targeting the H134R mutation for rapid screening of SDHI resistance in A. brassicicola. We also found that boscalid-resistant isolates exhibited significantly reduced mycelial growth. However, spore germination rates among different resistant isolates were not different, suggesting that resistant isolates remain competitive in natural populations. Overall, this study provides the first evidence of fungicide resistance to SDHI fungicides in A. brassicicola isolated from naturally infested broccoli seeds and underscores the importance of seeds as a potential source for introducing fungicide resistance across geographical locations.

    IMPORTANCE: Alternaria brassicicola is a fungal seed-borne pathogen that can be disseminated via commercial seeds across transplant houses and commercial broccoli fields. Our study provides the first evidence that commercial broccoli seeds can harbor pathogenic A. brassicicola isolates with cross-resistance to two succinate dehydrogenase inhibitor (SDHI) fungicides. We observed that 93% of the A. brassicicola isolates from naturally infested commercial broccoli seeds contained a point mutation that conferred resistance to two SDHI fungicides (boscalid and penthiopyrad). Furthermore, we developed a PCR-based allele-specific assay for the rapid detection and monitoring of fungicide resistance. Our study highlights the importance of seed health testing and potential dissemination of fungicide-resistant isolates locally and globally, thus impacting disease management strategies.

    PMID:40905662 | DOI:10.1128/aem.01083-25

  • Deciphering the Biochemical Functions and Nucleotide Sugar Donor Specificity Determinants of Dicot GT61 Glycosyltransferases Involved in Xylan Substitutions 

    Ruiqin Zhong

    Plant Cell Physiol. 2025 Sep 26:pcaf122. doi: 10.1093/pcp/pcaf122. Online ahead of print.

    ABSTRACT

    Plant cell wall polysaccharide glycosyltransferases catalyze the transfer of sugars from specific nucleotide sugar donors onto specific acceptor substrates. The mechanisms of how their enzymatic specificity is determined is one of the long-standing questions in plant cell wall biology. In this report, we studied the biochemical functions of Arabidopsis and poplar GT61 glycosyltransferases involved in xylan substitutions and investigated the molecular determinants of their nucleotide sugar donor specificity. Enzymatic activity assays of recombinant proteins of Arabidopsis and poplar GT61 members demonstrated that two of them, AtX2AT1 and PtrX2AT1, exhibited xylan 2-O-arabinosyltransferase activities specifically using UDP-Araf, two other ones, AtXYXT2/3, possessed xylan 2-O-xylosyltransferase activities specifically using UDP-Xyl, and three other ones, PtrXXAT1/2/3, were able to catalyze the transfer of 2-O-Araf and 2-O-Xyl onto xylan using both UDP-Araf and UDP-Xyl. Structural modeling and molecular docking of PtrXXAT1 identified amino acid residues involved in interacting with UDP-Araf and UDP-Xyl at the putative active site and site-directed mutagenesis revealed their critical roles in PtrXXAT1 catalytic activities. Furthermore, structural alignment and reciprocal swapping of UDP-Xyl-interacting residues of PtrXXAT1 with their corresponding residues of AtX2AT1 pinpointed key residues determining their nucleotide sugar donor specificity. Our results indicate that Arabidopsis and poplar GT61 members catalyze 2-O-Araf- and/or 2-O-Xyl substitutions of xylan and that subtle structural differences in their substrate-binding pockets could alter their substrate specificity toward nucleotide sugar donors.

    PMID:41001967 | DOI:10.1093/pcp/pcaf122

  • Design of genus-specific semi-nested primers for simple and accurate identification of Enterobacter strains 

    Sara Jordan

    BMC Microbiol. 2025 Jul 28;25(1):456. doi: 10.1186/s12866-025-04175-1.

    ABSTRACT

    BACKGROUND: The genus Enterobacter, in the family Enterobacteriaceae, is of both clinical and environmental importance. This genus has undergone frequent taxonomic changes, making it challenging to identify taxa even at genus level. This study aimed to design Enterobacter genus-specific primers that can be used for simple PCR identification of large sets of putative Enterobacter isolates.

    RESULTS: Comparative genomic approaches were employed to identify genes that were universally present on Enterobacter genomes but absent from the genomes of other members of the family Enterobacteriaceae, based on an initial set of 89 genomes. The presence of these genes was further confirmed in 4,276 Enterobacter RefSeq genomes. While no strictly genus-specific genes were identified, the hpaB gene demonstrated a restricted distribution outside of the genus Enterobacter. Semi-nested primers were designed for hpaB and its flanking gene hpaC (hpaBC) and evaluated on 123 strains in single-tube PCR reactions. All taxa showing positive reactions belonged to the genus Enterobacter. For Enterobacter strains the PCR yielded two amplicons at 110 bp and at 370 bp, while strains only displaying the 110 bp amplicon were classified as Leclercia pneumoniae. A blind-test on 120 strains accessioned as Enterobacter sp. from the USDA-ARS culture collection (NRRL), revealed that one third of the strains had an incorrect genus assignment. Comparison of gene trees of the hpaBC fragment sequences with marker genes frequently used for single-gene barcoding or multi-locus sequence analysis (MLSA) further demonstrated its potential for preliminary species identification.

    CONCLUSIONS: The nested PCR assay represents a rapid and cost-effective approach for preliminary identification of Enterobacter species. As the primer design was based on large-scale genomic comparison, including currently undescribed species clades, it will remain valid even after taxonomic changes within the genus.

    PMID:40722002 | DOI:10.1186/s12866-025-04175-1

2021 Cohort

  • 1H-NMR Guided Isolation of Bioactive Compounds from Species of the Genus Piper 

    Author: Ian S Wallace 

    Molecules. 2025 Apr 30;30(9):2020. doi: 10.3390/molecules30092020.

    ABSTRACT

    The discovery of bioactive natural products is often challenged by the complexity of isolating and characterizing active compounds within diverse mixtures. Previously, we introduced a 1H NMR-based weighted gene correlation network analysis (WGCNA) approach to identify spectral features linked to growth inhibitory activity of Piper (Piperaceae) leaf extracts against model plant, fungal, and bacterial organisms. This method enabled us to prioritize specific spectral features linked to bioactivity, offering a targeted approach to natural product discovery. In this study, we validate the predictive capacity of the WGCNA by isolating the compounds responsible for the bioactivity-associated resonances and confirming their antifungal efficacy. Using growth inhibition assays, we verified that the isolated compounds, including three novel antifungal agents, exhibited significant bioactivity. Notably, one of these compounds contains a rare imidazolium heterocyclic motif, marking a new structural class in Piper. These findings substantiate the 1H NMR-based WGCNA as a reliable tool for identifying structural types associated with biological activity, streamlining the process of discovering bioactive natural products in complex extracts.

    PMID:40363825 | PMC:PMC12073215 | DOI:10.3390/molecules30092020

  • 2023 Retreat Agenda

  • 2025 Spring Symposium Save the Date

  • 35th E. S. Luttrell Lecture

  • A Case Study for Visual Detection of a Systemic Disease: Optimizing Identification of Phony Peach Disease Based on Statistical and Machine Learning Models 

    Weiqi Luo

    Phytopathology. 2025 Jun 22. doi: 10.1094/PHYTO-03-25-0093-R. Online ahead of print.

    ABSTRACT

    Phony peach disease (PPD), caused by Xylella fastidiosa subsp. multiplex (Xfm), poses a significant threat to commercial peach orchards in Georgia. Early and accurate detection is essential for effective disease management, yet visual assessment remains the primary approach for diagnosing PPD symptoms due to the high cost and logistical challenges of qPCR-based detection of Xfm. We evaluated the accuracy of visual PPD assessment and examined the factors influencing rater performance, symptom reliability, and optimal survey deployment strategies with CART/Random Forest analyses and simulations. Internode length was the most reliable symptom for PPD identification in two peach cultivars, consistently outperforming other physical traits such as canopy flatness and shape. Primer pair C06Xf-bamA had the greatest relative sensitivity, making it the preferred choice for qPCR confirmation. Principal component analysis suggested that rater experience significantly improved agreement with qPCR results and repeated assessments of the same orchards further enhanced consistency for raters. Simulations results suggested that deploying two experienced raters may provide the highest detection diagnostic accuracy for survey purposes, particularly when qPCR-based pathogen detection is unavailable. Last, PPD-affected trees, through PCR verification and visual identification, exhibited higher mortality rates than Xfm-negative trees, reinforcing the need for early detection and removal to limit disease spread. These findings underscore the importance of strategic rater deployment, targeted symptom selection, and integrating molecular diagnostics when feasible.

    PMID:40544457 | DOI:10.1094/PHYTO-03-25-0093-R

  • A cell-type-specific regulon controlling monoterpene indole alkaloid biosynthesis with feedback and feedforward activation loops 

    Chenxin Li

    New Phytol. 2025 Nov 9. doi: 10.1111/nph.70712. Online ahead of print.

    ABSTRACT

    Monoterpene indole alkaloids (MIA) are a diverse class of plant natural products produced by a subset of lineages within the Asterid clade of eudicots. The diversity of MIAs provides a unique opportunity to study not only the evolution of biosynthetic genes but also their regulation. In this study, we investigate the cell type specificity of biosynthetic genes and coexpressed transcription factors (TFs) in two MIA-producing Asterid species, Catharanthus roseus, a well-studied MIA-producing species, and Camptotheca acuminata, which belongs to an early-diverging lineage of the Asterid clade. We generated single-cell RNA-seq data from the C. acuminata stem, the primary site of camptothecin biosynthesis. We found that MIA biosynthetic genes in C. acuminata are specific to exceptionally rare cell populations. We discovered MYB and bHLH TFs coexpressed in the same cell types as MIA biosynthetic genes in the C. acuminata stem. Interestingly, the C. roseus orthologs of these TFs are idioblast-specific and activate MIA biosynthetic genes in C. roseus upon overexpression. We constructed an extended gene regulatory network for the idioblast metabolic regulon in C. roseus, which contains both feedback and feedforward activation loops. This study demonstrates co-option of the same clades of TFs for regulation of cell-type-specific MIA biosynthesis across two Asterid species separated by c. 115 million years of evolution. Investigating cell-type-specific TFs that are coexpressed with biosynthetic genes across multiple species is a powerful strategy to increase the power for the discovery of plant metabolic regulators.

    PMID:41208325 | DOI:10.1111/nph.70712

  • A compendium of nonredundant short polymerase III promoters for CRISPR applications 

    Michihito Deguchi

    Plant Physiol. 2025 Jul 3;198(3):kiaf294. doi: 10.1093/plphys/kiaf294.

    ABSTRACT

    Minimal native and synthetic Polymerase III promoters enable efficient and customizable CRISPR multiplexing in plants, expanding genome engineering capabilities

    PMID:40673482 | PMC:PMC12268498 | DOI:10.1093/plphys/kiaf294

  • A global dataset of terrestrial biological nitrogen fixation 

    Carla R Reis Ely

    Sci Data. 2025 Aug 5;12(1):1362. doi: 10.1038/s41597-025-05131-4.

    ABSTRACT

    Biological nitrogen fixation (BNF) is the main natural source of new nitrogen inputs in terrestrial ecosystems, supporting terrestrial productivity, carbon uptake, and other Earth system processes. We assembled a comprehensive global dataset of field measurements of BNF in all major N-fixing niches across natural terrestrial biomes derived from the analysis of 376 BNF studies. The dataset comprises 32 variables, including site location, biome type, N-fixing niche, sampling year, quantification method, BNF rate (kg N ha-1 y-1), the percentage of nitrogen derived from the atmosphere (%Ndfa), N fixer or N-fixing substrate abundance, BNF rate per unit of N fixer abundance, and species identity. Overall, the dataset combines 1,207 BNF rates for trees, shrubs, herbs, soil, leaf litter, woody litter, dead wood, mosses, lichens, and biocrusts, 152 herb %Ndfa values, 1,005 measurements of N fixer or N-fixing substrate abundance, and 762 BNF rates per unit of N fixer abundance for a total of 424 species across 66 countries. This dataset facilitates synthesis, meta-analysis, upscaling, and model benchmarking of BNF fluxes at multiple spatial scales.

    PMID:40764484 | DOI:10.1038/s41597-025-05131-4

  • A high-quality genome assembly of the tetraploid Teucrium chamaedrys unveils a recent whole genome duplication and a large biosynthetic gene cluster for diterpenoid metabolism 

    Abigail E Bryson

    Plant Commun. 2025 Jun 3:101393. doi: 10.1016/j.xplc.2025.101393. Online ahead of print.

    ABSTRACT

    Teucrium chamaedrys, also called wall germander, is a small woody shrub native to the Mediterranean region. Its name is derived from the Greek words meaning ‘ground oak’, since its tiny leaves resemble those of an oak tree. Teucrium species are proliferative producers of diterpenes, which afford them valuable properties widely co-opted in traditional and western medicines. Sequence and assembly of the 3 Gbp tetraploid T. chamaedrys revealed 74 diterpene synthase genes, with the vast representation of these diterpene synthases clustered along four genomic loci. Comparative genomics revealed that this cluster is mirrored in the closely related species, Teucrium marum. Along with the presence of several cytochrome p450 sequences, this region is the one of largest biosynthetic gene clusters identified. Teucrium is well known for accumulating clerodane-type diterpenoids which are produced from a kolavanyl diphosphate precursor. To elucidate the complex biosynthetic pathways of these medicinal compounds, we identified and functionally characterized several kolavanyl diphosphate synthases from T. chamaedrys. Its remarkable chemistry and tetraploidy make T. chamaedrys an interesting and unique model for studying genomic evolution and adaptation in plants.

    PMID:40468595 | DOI:10.1016/j.xplc.2025.101393

  • A nitric oxide reductase is a key enzyme target for eliminating fungal emissions of nitrous oxide 

    Blake A Oakley

    Fungal Genet Biol. 2025 Sep 23:104038. doi: 10.1016/j.fgb.2025.104038. Online ahead of print.

    ABSTRACT

    Nitrous oxide (N2O) derived from agricultural activity is a major contributor to Earth’s greenhouse effect. Synthetic nitrogen fertilizer applied at high levels, particularly combined with heavy rainfall events, generates hot spots of N2O emissions in agricultural fields due to the process of microbial denitrification. Here, a key conserved fungal denitrification enzyme necessary for N2O emissions was identified. Phylogenetic analysis revealed that fungal NOR1-like genes, with rare exceptions, are highly conserved and confined to the phylum Ascomycota. Plant pathogenic Fusarium species that possess NOR1 exhibited drastic differences in N2O production based on denitrification potential. Functional characterization of the p450nor nitric oxide reductase encoding gene, NOR1, in the soil-borne denitrifying maize pathogen, Fusarium verticillioides, showed that this enzyme is critical for fungal N2O production. Deletion of the single copy NOR1 gene in F. verticillioides eliminated N2O emissions. Complementation of deletion mutants via the NOR1 gene add-back restored wild type N2O emission levels and segregation analysis further corroborated the pivotal role of NOR1 for N2O emissions. We suggest targeting of the NOR1 enzyme as an effective strategy to reduce fungal-based N2O emissions.

    PMID:40998212 | DOI:10.1016/j.fgb.2025.104038

  • Aerial root formation in Oaxacan maize (Zea mays) landraces persists into the adult phase and is minimally affected by soil nitrogen and ambient humidity 

    Rafael E Venado

    Front Plant Sci. 2025 Jul 11;16:1607733. doi: 10.3389/fpls.2025.1607733. eCollection 2025.

    ABSTRACT

    Maize (Zea mays L.) is the most widely produced crop in the world, and conventional production requires significant amounts of synthetic nitrogen fertilizer, which has negative economic and environmental consequences. Maize landraces from Oaxaca, Mexico, can acquire nitrogen from nitrogen-fixing bacteria that live in a mucilage secreted by aerial nodal roots. The development of these nodal roots is a characteristic traditionally associated with the juvenile vegetative stage of maize plants. However, mature Oaxacan landraces develop many more nodes with aerial roots than commercial maize varieties. Our study shows that Oaxacan landraces develop aerial roots during the juvenile and adult vegetative phases and even during early flowering under greenhouse and field conditions. Surprisingly, the development of these roots was only minimally affected by soil nitrogen and ambient humidity. These findings are an essential first step in developing maize varieties to reduce fertilizer needs in maize production across different environmental conditions.

    PMID:40718026 | PMC:PMC12289584 | DOI:10.3389/fpls.2025.1607733

  • An updated sulfate transporter phylogeny uncovers a perennial-specific subgroup associated with lignification 

    Samantha M Surber

    Tree Physiol. 2025 Jul 11:tpaf080. doi: 10.1093/treephys/tpaf080. Online ahead of print.

    ABSTRACT

    Sulfate-proton co-transporters (SULTRs) mediate sulfate uptake, transport, storage, and assimilation in plants. The SULTR family has historically been classified into four groups (SULTR1-SULTR4), with well-characterized roles for SULTR groups 1, 2, and 4. However, the functions of the large and diverse SULTR3 group remain poorly understood. Here, we present an updated phylogenetic analysis of SULTRs across angiosperms, including multiple early-divergent lineages. Our results suggest that the enigmatic SULTR3 group comprises four distinct subfamilies that predate the emergence of angiosperms, providing a basis for reclassifying the SULTR family into seven subfamilies. This expanded classification is supported by subfamily-specific gene structures and amino acid substitutions in the substrate-binding pocket. Structural modeling identified three serine residues uniquely lining the substrate-binding pocket of SULTR3.4, enabling three hydrogen bonds with the phosphate ion. The data support the proposed neofunctionalization of this subfamily for phosphate allocation within vascular tissues. Transcriptome analysis of Populus tremula × alba revealed divergent tissue expression preferences among SULTR subfamilies and between genome duplicates. We observed partitioned expression in vascular tissues among the four SULTR3 subfamilies, with PtaSULTR3.4a and PtaSULTR3.2a preferentially expressed in primary and secondary xylem, respectively. Gene coexpression analysis revealed coordinated expression of PtaSULTR3.4a with genes involved in phosphate starvation responses and nutrient transport, consistent with a potential role in phosphate homeostasis. In contrast, PtaSULTR3.2a was strongly coexpressed with lignification and one-carbon metabolism genes and their upstream transcription regulators. PtaSULTR3.2a belongs to a eudicot-specific branch of the SULTR3.1 subfamily found only in perennial species, suggesting a specialized role in lignifying tissues. Together, our findings provide a refined phylogenetic framework for the SULTR family and suggest that the expanded SULTR3 subfamilies have undergone neofunctionalization during the evolution of vascular and perennial plants.

    PMID:40643194 | DOI:10.1093/treephys/tpaf080

  • Anionic lipids direct efficient microfluidic encapsulation of stable and functionally active proteins in lipid nanoparticles 

    Suresh Ambati

    Commun Mater. 2025;6(1):34. doi: 10.1038/s43246-025-00749-8. Epub 2025 Feb 22.

    ABSTRACT

    Because proteins do not efficiently pass through the plasma membrane, protein therapeutics are limited to target ligands located at the cell surface or in serum. Lipid nanoparticles can facilitate delivery of polar molecules across a membrane. We hypothesized that because most proteins are amphoteric ionizable polycations, proteins would associate with anionic lipids, enabling microfluidic chip assembly of stable EP-LNPs (Encapsulated Proteins in Lipid NanoParticles). Here, by employing anionic lipids we were able to efficiently load proteins into EP-LNPs at protein:lipid w:w ratios of 1:20. Several proteins with diverse molecular weights and isoelectric points were encapsulated at efficiencies of 70 75%-90% and remained packaged for several months. Proteins packaged in EP-LNPs efficiently entered mammalian cells and fungal cells with cell walls. The proteins delivered intracellularly were functional. EP-LNPs technology should improve cellular delivery of medicinal antibodies, enzymes, peptide antimetabolites, and dominant negative proteins, opening new fields of protein therapeutics.

    PMID:41146908 | PMC:PMC12553553 | DOI:10.1038/s43246-025-00749-8

  • Anne Frances Jarrell wins 1st Place at the NAPB 2023 Poster Competition!

    Anne Frances Jarrell from the 2021 Cohort won first place for the PhD Poster Competition at the 2023 National Association of Plant Breeders meeting!

    In Spring 2022, Anne Frances officially joined the Robin Buell lab as a Graduate Research Assistant. She is interested in using advances in genomics to improve crop breeding, specifically to increase sustainability and crop resiliency in the face of global climate change. Currently, this leads her to work with potatoes and their wild relatives.

    Learn more about Anne Frances and her work by visiting the Buell Lab website!

    Congratulations Anne Frances!

  • Assessing UV-C radiation treatments for dollar spot suppression in seashore paspalum 

    Willis Turner Spratling

    Plant Dis. 2025 Dec 8. doi: 10.1094/PDIS-08-24-1610-RE. Online ahead of print.

    ABSTRACT

    Dollar spot, caused by Clarireedia spp., is one of the most detrimental diseases of turfgrass worldwide, and control strategies usually involve frequent fungicide applications. These treatments are expensive, require special equipment and can contribute to fungicide resistance issues, underscoring the need for alternative management strategies. UV-C radiation has proven effective as a disease management tool in various cropping systems but is still largely unexplored in turfgrass. This study aimed to test the effects of UV-C radiation against dollar spot in seashore paspalum and to evaluate its impact on plant health and performance. In assessing UV-C’s efficacy directly against C. monteithiana, daily radiation treatments ranging from 27.5 J m-2 to 77.0 J m-2 were shown to effectively reduce mycelial growth. Additionally, in vitro UV-C treatment administered in darkness was observed to be more effective in reducing pathogen growth than treatment administered in lighted conditions. In a growth chamber setting, daily 66.0 J m-2 UV-C treatment significantly reduced dollar spot severity in seashore paspalum without causing phytotoxic damage to plant tissues. In field trials, a novel UV-C application system was implemented by modifying a robotic mower to autonomously deliver UV-C radiation to seashore paspalum plots. UV-C treatment in the field significantly reduced dollar spot severity. Moreover, UV-C treatment led to several physiological and performance enhancements, including increased chlorophyll content, shoot density, surface firmness, and green speed. Findings from this study indicate that UV-C radiation may be used as an effective physical control to complement existing dollar spot management practices.

    PMID:41362131 | DOI:10.1094/PDIS-08-24-1610-RE

  • Biology, Ecology, and Management of Prevalent Thrips Species (Thysanoptera: Thripidae) Impacting Blueberry Production in the Southeastern United States 

    Rosan Adhikari

    Insects. 2025 Jun 24;16(7):653. doi: 10.3390/insects16070653.

    ABSTRACT

    Blueberry is a high-value fruit crop in the United States, with Georgia and Florida serving as important early-season production regions. In these areas, several thrips species (Thysanoptera: Thripidae), including Frankliniella tritici (Fitch), Frankliniella bispinosa (Morgan), and Scirtothrips dorsalis (Hood), have emerged as economically significant pests. While F. tritici and F. bispinosa primarily damage floral tissues, S. dorsalis targets young foliage. Their rapid reproduction, high mobility, and broad host range contribute to rapid population buildup and complicate the management programs. Species identification is often difficult due to overlapping morphological features and requires the use of molecular diagnostic tools for accurate identification. Although action thresholds, such as 2-6 F. tritici per flower cluster, are used to guide management decisions, robust economic thresholds based on yield loss remain undeveloped. Integrated pest management (IPM) practices include regular monitoring, cultural control (e.g., pruning, reflective mulch), biological control using Orius insidiosus (Say) and predatory mites, and chemical control. Reduced-risk insecticides like spinetoram and spinosad offer effective suppression while minimizing harm to pollinators and beneficial insects. However, the brief flowering period limits the establishment of biological control agents. Developing species-specific economic thresholds and phenology-based IPM strategies is critical for effective and sustainable thrips management in blueberry cropping systems.

    PMID:40725285 | DOI:10.3390/insects16070653

  • Bordetellae colonization oligosaccharide (b-Cool), a glycan crucial for nasal colonization 

    Yang Su

    Sci Adv. 2025 Sep 5;11(36):eadw7764. doi: 10.1126/sciadv.adw7764. Epub 2025 Sep 3.

    ABSTRACT

    Respiratory tract infections pose considerable global health challenges. Upper airway colonization is pivotal to these infections, including those caused by Bordetella species. We identified an oligosaccharide, bordetellae colonization oligosaccharide (b-Cool), crucial for early nasal colonization of Bordetella bronchiseptica. We characterized the structure of b-Cool by LC-MS and NMR and found that it is prevalent across a diverse range of bordetellae, including Bordetella pertussis, which causes whooping cough in humans. A B. bronchiseptica mutant lacking b-Cool (Δb-Cool) showed significantly delayed and decreased colonization in mouse nasopharynx and nasal epithelia, resulting in decreased transmission. The colonization defect of Δb-Cool was rescued in mucin deficient mice, suggesting that b-Cool may facilitate colonization in the presence of airway mucins.

    PMID:40901963 | DOI:10.1126/sciadv.adw7764

  • Building an expanded bio-based economy through synthetic biology 

    Andrea M Garza Elizondo

    Biotechnol Adv. 2025 Dec 6:108775. doi: 10.1016/j.biotechadv.2025.108775. Online ahead of print.

    ABSTRACT

    The field of synthetic biology is essential to the continued development of a bio-based economy, creating mechanisms to supply carbon needed in the economy by both converting existing end-of-life wastes as well as by creating novel, purpose-grown and sustainable feedstocks. Here, we first discuss the near- and long-term resources available for use as feedstocks for bioconversion as well as the output molecules needed for building the foundation of an expanded bio-based economy. We then outline the organisms and phenotypic traits that are needed for the performance-advantaged chassis organisms of the future. Furthermore, we detail the advances, challenges, and opportunities in both microbial and plant synthetic biology relevant to expanding the bio-based economy. Finally, we explore technologies that have and will further enable advances in synthetic biology and the greater bio-based economy.

    PMID:41360191 | DOI:10.1016/j.biotechadv.2025.108775

  • Building genomic resources to facilitate the study and use of Solanum microdontum, a wild relative of cultivated potato 

    Anne Frances Jarrell

    G3 (Bethesda). 2025 Oct 23:jkaf253. doi: 10.1093/g3journal/jkaf253. Online ahead of print.

    ABSTRACT

    Solanum microdontum Bitter is a diploid wild Andean relative of potato that has shaped the domestication and adaptation of modern cultivated potato to diverse environments. Solanum microdontum has the potential to provide a wealth of untapped genetic material for use in addressing current challenges in potato breeding. Here, we report a high-quality 772 Mb reference genome sequence for S. microdontum that is anchored to 12 chromosomes. The resulting genome assembly has 99.0% complete Benchmarking Universal Single Copy Orthologs and an N50 scaffold length of over 57 Mb, indicating a high level of completeness. Annotation of the assembly resulted in the identification of 37,324 protein coding genes and 65% repetitive sequence. A total of 1,187 nucleotide-binding leucine-rich repeat genes were predicted from the assembly, of which 93.1% overlapped an annotated high-confidence gene model. A k-mer based kinship matrix derived from a 107-member S. microdontum diversity panel revealed an underlying population structure that corresponds to geographic proximity. The S. microdontum dataset enhances publicly available potato genome resources by providing breeders with genetic, molecular, and germplasm resources for newly developed diploid potato breeding programs.

    PMID:41128648 | DOI:10.1093/g3journal/jkaf253

  • Candidate genes at the Rmi1 locus for resistance to Meloidogyne incognita in soybean 

    Kelly Goode

    Theor Appl Genet. 2025 Oct 29;138(11):286. doi: 10.1007/s00122-025-05065-w.

    ABSTRACT

    The RKN resistance locus Rmi1 was fine-mapped to two genes on chromosome 10, a glycosyl hydrolase family 9 β-1,4-endoglucanase gene and a type I pectin methylesterase gene. Root-knot nematodes (Meloidogyne spp.) are a serious threat to soybean production in the southeast USA, with yield losses of more than $165 million in 2023. Development and deployment of resistant soybean cultivars is the most effective strategy for managing these nematode pests; however, the identity of the resistance genes and underlying mechanism of resistance remains obscure. An additive resistance gene, Resistance to M. incognita-1 (Rmi1), to the predominant species, was first identified in soybean cultivar Forrest but never mapped to a genomic region. Multiple mapping studies have identified a major quantitative trait locus (QTL) with additive action on chromosome 10. In this study, a population consisting of 170 F2:3 families derived from a cross of Bossier (susceptible) × Forrest (resistant) was initially used to confirm that Rmi1 is in the chromosome 10 QTL. Subsequently, 884 F5:6 recombinant inbred lines (RILs) derived from the same cross were used to fine-map the Rmi1 causal gene(s) to two genes – a β-1,4-endoglucanase (Glyma.10G017000, EG) and a pectin methylesterase/methylesterase inhibitor (Glyma.10G017100, PME1). Both gene candidates have the potential to play a role in the resistance response to M. incognita. Both gene promoters harbor SNPs and indels and the encoded proteins exhibit amino acid polymorphisms, including a premature stop in PME1 of resistant soybeans. Additionally, both genes show a higher expression level in susceptible roots compared to resistant roots in the absence of infection. This suggests that Rmi1 may confer one or more pre-existing differences related to cell wall modification in soybean roots, ultimately leading to a decrease in susceptibility.

    PMID:41160124 | DOI:10.1007/s00122-025-05065-w

  • Celebrating the fifth edition of the International Symposium on Fungal Stress – ISFUS, a decade after its 2014 debut 

    Alene Alder-Rangel

    Fungal Biol. 2025 Aug;129(5):101590. doi: 10.1016/j.funbio.2025.101590. Epub 2025 May 6.

    ABSTRACT

    The Fifth International Symposium on Fungal Stress (ISFUS) brought together in Brazil many of the leaders in the field of fungal stress responses, from fourteen countries, for four days of outstanding science ranging from basic research to studies with agricultural, medical, industrial, and environmental significance. In addition to the excellent oral and poster presentations, the Symposium organisers ensured that all participants had ample opportunity to engage, socialise, and network to exchange ideas and share research. The conference was enhanced by the world-class venue near Iguazu Falls, probably the greatest natural phenomenon in South America.

    PMID:40707112 | DOI:10.1016/j.funbio.2025.101590

  • Characterization of Pseudomonas alliivorans strains isolated from Georgia, USA: insights into genomic diversity and pathogenicity in onions 

    Mei Zhao

    Appl Environ Microbiol. 2025 Nov 25:e0164325. doi: 10.1128/aem.01643-25. Online ahead of print.

    ABSTRACT

    Pseudomonas alliivorans is an important emerging pathogen affecting numerous crops. The species is closely related to Pseudomonas viridiflava, with which P. alliivorans strains were often misidentified in the past. Here, we investigated the genetic and pathogenic characteristics of P. alliivorans strains isolated primarily from onions and weeds in Georgia, USA, using whole-genome sequencing, comparative genomics, and functional assays. We delineated the core genome and genetic diversity of these isolates, assessed their pathogenicity on onion foliage and red onion scales, and examined the roles of key virulence determinants (Hrp1-type III secretion system [T3SS], rhizobium-T3SS, type II secretion systems [T2SSs], and thiosulfinate [allicin]-tolerance alt cluster). Our results showed that the Hrp1-T3SS is pivotal for pathogenicity in P. alliivorans, whereas the rhizobium-T3SS, T2SSs, and alt cluster do not contribute to symptom development on red onion scales. Notably, the alt cluster confers in vitro thiosulfinate tolerance, supporting bacterial survival against onion-derived antimicrobial compounds. Additionally, homologous recombination in P. alliivorans occurs infrequently (at approximately one-tenth the rate of point mutations) and involves divergent DNA segments. The alt cluster is acquired through horizontal gene transfer, as evidenced by its lower GC content and the presence of adjacent transposases. In summary, our research provides valuable insights into the genetic diversity, evolutionary dynamics, and virulence mechanisms of P. alliivorans strains from Georgia, USA.IMPORTANCEPseudomonas alliivorans is an emerging plant pathogen that threatens onion and other plants of economic importance. This study identifies key traits that help this bacterium cause disease, such as a specific secretion system critical for infecting onions, and a gene cluster that aids bacterial survival in onion tissues. Beyond highlighting weed as a potential inoculum source and supporting better weed management, the findings of this research open avenues for more targeted disease menegement. By unraveling the genetics of this pathogen, we can develop improved ways to detect, prevent, and reduce its impact, protecting crop health and yields.

    PMID:41288358 | DOI:10.1128/aem.01643-25

  • Comparative Analyses of Four Reference Genomes Reveal Exceptional Diversity and Weak Linked Selection in the Yellow Monkeyflower (Mimulus guttatus) Complex 

    John T Lovell

    Mol Ecol Resour. 2025 Jul 22:e70012. doi: 10.1111/1755-0998.70012. Online ahead of print.

    ABSTRACT

    Yellow monkeyflowers (Mimulus guttatus complex, Phrymaceae) are a powerful system for studying ecological adaptation, reproductive variation, and genome evolution. To initiate pan-genomics in this group, we present four chromosome-scale assemblies and annotations of accessions spanning a broad evolutionary spectrum: two from a single M. guttatus population, one from the closely related selfing species M. nasutus, and one from a more divergent species M. tilingii. All assemblies are highly complete and resolve centromeric and repetitive regions. Comparative analyses reveal such extensive structural variation in repeat-rich, gene-poor regions that large portions of the genome are unalignable across accessions. As a result, this Mimulus pan-genome is primarily informative in genic regions, underscoring limitations of resequencing approaches in such polymorphic taxa. We document gene presence-absence, investigate the recombination landscape using high-resolution linkage data, and quantify nucleotide diversity. Surprisingly, pairwise differences at fourfold synonymous sites are exceptionally high-even in regions of very low recombination-reaching ~3.2% within a single M. guttatus population, ~7% within the interfertile M. guttatus species complex (approximately equal to SNP divergence between great apes and Old World monkeys), and ~7.4% between that complex and the reproductively isolated M. tilingii. Genome-wide patterns of nucleotide variation show little evidence of linked selection, and instead suggest that the concentration of genes (and likely selected sites) in high-recombination regions may buffer diversity loss. These assemblies, annotations, and comparative analyses provide a robust genomic foundation for Mimulus research and offer new insights into the interplay of recombination, structural variation, and molecular evolution in highly diverse plant genomes.

    PMID:40693537 | DOI:10.1111/1755-0998.70012

  • Comparative Transcriptomic Analysis of Soybean Recombinant Inbred Lines Differing at the Rmi1 Locus for Resistance to Meloidogyne incognita During Early Stages of Nematode Infection 

    Kelly Goode

    Phytopathology. 2025 Jun 11. doi: 10.1094/PHYTO-04-25-0143-SC. Online ahead of print.

    ABSTRACT

    Root-knot nematodes (Meloidogyne spp.) are a continuing threat to soybean production, with M. incognita being the predominant species. The deployment of Mi-resistant soybean cultivars is a primary management strategy, but the underlying molecular mechanisms contributing to resistance remain unknown. A single, additive gene for resistance to M. incognita, Rmi1, was previously identified in soybean cv. Forrest and associated with the emigration of second-stage juveniles from the roots. To better understand the Rmi1-mediated resistance response, we used Forrest-derived F5 RILs differing for Rmi1 to analyze global changes in gene expression in response to M. incognita infection at 2- and 4-days post inoculation. We identified 1,471 differentially expressed (DE) genes in the compatible interaction and 1,037 DE genes in the incompatible interaction. Forty-five percent of DE genes were DE in both interactions, 42% (856) were unique to the compatible interaction, and 13% (261) were unique to the incompatible interaction. Genes uniquely DE in the incompatible interaction included genes involved in cell wall modification, hormone signaling, endomembrane trafficking, and redox reactions providing new insights into the resistance mechanism mediated by Rmi1 in soybean to root-knot nematodes.

    PMID:40498525 | DOI:10.1094/PHYTO-04-25-0143-SC

  • Conflicting kinesin-14s in a single chromosomal drive haplotype 

    Author: Kelly Dawe

    Genetics. 2025 May 14:iyaf091. doi: 10.1093/genetics/iyaf091. Online ahead of print.

    ABSTRACT

    In maize, there are two meiotic drive systems that target large heterochromatic knobs composed of tandem repeats known as knob180 and TR-1. The first meiotic drive haplotype, Abnormal chromosome 10 (Ab10) confers strong meiotic drive (∼75% transmission as a heterozygote) and encodes two kinesins: KINDR, which associates with knob180 repeats and TRKIN, which associates with TR-1 repeats. Prior data show that meiotic drive is conferred primarily by the KINDR/knob180 system while the TRKIN/TR-1 system seems to have little or no role, making it unclear why Trkin has been maintained in Ab10 haplotypes. The second meiotic drive haplotype, K10L2, confers a low level of meiotic drive (∼51-52%) and only encodes the TRKIN/TR-1 system. Here we used long-read sequencing to assemble the K10L2 haplotype and showed that it has strong homology to an internal portion of the Ab10 haplotype. We also carried out CRISPR mutagenesis to test the role of Trkin on Ab10 and K10L2. The data indicate that the Trkin gene on Ab10 does not improve drive or fitness but instead has a weak deleterious effect when paired with a normal chromosome 10. The deleterious effect is more severe when Ab10 is paired with K10L2: in this context functional Trkin on either chromosome nearly abolishes Ab10 drive. Mathematical modeling based on the empirical data suggest that Trkin is unlikely to persist on Ab10. We conclude that Trkin either confers an advantage to Ab10 in untested circumstances or that it is in the process of being purged from the Ab10 population.

    PMID:40365704 | DOI:10.1093/genetics/iyaf091

  • Correction: Drought adaptation index (DAI) based on BLUP as a selection approach for drought-resilient switchgrass germplasm 

    Shiva Om Makaju

    Front Genet. 2025 Nov 12;16:1731825. doi: 10.3389/fgene.2025.1731825. eCollection 2025.

    ABSTRACT

    [This corrects the article DOI: 10.3389/fgene.2025.1626083.].

    PMID:41311856 | PMC:PMC12648043 | DOI:10.3389/fgene.2025.1731825

  • Cross-resistance in Alternaria brassicicola from naturally infested broccoli seeds against two succinate dehydrogenase inhibitor fungicides 

    Navjot Kaur

    Appl Environ Microbiol. 2025 Sep 4:e0108325. doi: 10.1128/aem.01083-25. Online ahead of print.

    ABSTRACT

    Seeds can serve as a vehicle for the dissemination of pests and pathogens around the world. We recently demonstrated the association of pathogenic Alternaria brassicicola isolates with reduced sensitivity to azoxystrobin (quinone-outside inhibitor [QoI]) in naturally infested commercial broccoli seeds. In this study, we further demonstrate that these isolates were also resistant to two succinate dehydrogenase inhibitor (SDHI) fungicides. Sensitivity of representative A. brassicicola isolates (n = 58) from naturally infested broccoli seedlots to QoI and SDHI fungicides was evaluated under in vitro conditions. Interestingly, 15% (n = 9/58) of the A. brassicicola isolates with reduced sensitivity to azoxystrobin also displayed reduced sensitivity to two commonly used SDHI fungicides (boscalid and penthiopyrad) in broccoli, indicating a potential case of cross-resistance to SDHI fungicides. Ninety-three percent of the isolates (n = 54/58) were resistant to both boscalid and penthiopyrad, while 100% isolates displayed sensitivity to fluopyram. Sequence analysis of sdh genes revealed the presence of only one point mutation (H134R) in the sdhC gene in isolates that displayed resistance to boscalid and penthiopyrad. We also developed and validated allele-specific primers targeting the H134R mutation for rapid screening of SDHI resistance in A. brassicicola. We also found that boscalid-resistant isolates exhibited significantly reduced mycelial growth. However, spore germination rates among different resistant isolates were not different, suggesting that resistant isolates remain competitive in natural populations. Overall, this study provides the first evidence of fungicide resistance to SDHI fungicides in A. brassicicola isolated from naturally infested broccoli seeds and underscores the importance of seeds as a potential source for introducing fungicide resistance across geographical locations.

    IMPORTANCE: Alternaria brassicicola is a fungal seed-borne pathogen that can be disseminated via commercial seeds across transplant houses and commercial broccoli fields. Our study provides the first evidence that commercial broccoli seeds can harbor pathogenic A. brassicicola isolates with cross-resistance to two succinate dehydrogenase inhibitor (SDHI) fungicides. We observed that 93% of the A. brassicicola isolates from naturally infested commercial broccoli seeds contained a point mutation that conferred resistance to two SDHI fungicides (boscalid and penthiopyrad). Furthermore, we developed a PCR-based allele-specific assay for the rapid detection and monitoring of fungicide resistance. Our study highlights the importance of seed health testing and potential dissemination of fungicide-resistant isolates locally and globally, thus impacting disease management strategies.

    PMID:40905662 | DOI:10.1128/aem.01083-25

  • Deciphering the Biochemical Functions and Nucleotide Sugar Donor Specificity Determinants of Dicot GT61 Glycosyltransferases Involved in Xylan Substitutions 

    Ruiqin Zhong

    Plant Cell Physiol. 2025 Sep 26:pcaf122. doi: 10.1093/pcp/pcaf122. Online ahead of print.

    ABSTRACT

    Plant cell wall polysaccharide glycosyltransferases catalyze the transfer of sugars from specific nucleotide sugar donors onto specific acceptor substrates. The mechanisms of how their enzymatic specificity is determined is one of the long-standing questions in plant cell wall biology. In this report, we studied the biochemical functions of Arabidopsis and poplar GT61 glycosyltransferases involved in xylan substitutions and investigated the molecular determinants of their nucleotide sugar donor specificity. Enzymatic activity assays of recombinant proteins of Arabidopsis and poplar GT61 members demonstrated that two of them, AtX2AT1 and PtrX2AT1, exhibited xylan 2-O-arabinosyltransferase activities specifically using UDP-Araf, two other ones, AtXYXT2/3, possessed xylan 2-O-xylosyltransferase activities specifically using UDP-Xyl, and three other ones, PtrXXAT1/2/3, were able to catalyze the transfer of 2-O-Araf and 2-O-Xyl onto xylan using both UDP-Araf and UDP-Xyl. Structural modeling and molecular docking of PtrXXAT1 identified amino acid residues involved in interacting with UDP-Araf and UDP-Xyl at the putative active site and site-directed mutagenesis revealed their critical roles in PtrXXAT1 catalytic activities. Furthermore, structural alignment and reciprocal swapping of UDP-Xyl-interacting residues of PtrXXAT1 with their corresponding residues of AtX2AT1 pinpointed key residues determining their nucleotide sugar donor specificity. Our results indicate that Arabidopsis and poplar GT61 members catalyze 2-O-Araf- and/or 2-O-Xyl substitutions of xylan and that subtle structural differences in their substrate-binding pockets could alter their substrate specificity toward nucleotide sugar donors.

    PMID:41001967 | DOI:10.1093/pcp/pcaf122

  • Design of genus-specific semi-nested primers for simple and accurate identification of Enterobacter strains 

    Sara Jordan

    BMC Microbiol. 2025 Jul 28;25(1):456. doi: 10.1186/s12866-025-04175-1.

    ABSTRACT

    BACKGROUND: The genus Enterobacter, in the family Enterobacteriaceae, is of both clinical and environmental importance. This genus has undergone frequent taxonomic changes, making it challenging to identify taxa even at genus level. This study aimed to design Enterobacter genus-specific primers that can be used for simple PCR identification of large sets of putative Enterobacter isolates.

    RESULTS: Comparative genomic approaches were employed to identify genes that were universally present on Enterobacter genomes but absent from the genomes of other members of the family Enterobacteriaceae, based on an initial set of 89 genomes. The presence of these genes was further confirmed in 4,276 Enterobacter RefSeq genomes. While no strictly genus-specific genes were identified, the hpaB gene demonstrated a restricted distribution outside of the genus Enterobacter. Semi-nested primers were designed for hpaB and its flanking gene hpaC (hpaBC) and evaluated on 123 strains in single-tube PCR reactions. All taxa showing positive reactions belonged to the genus Enterobacter. For Enterobacter strains the PCR yielded two amplicons at 110 bp and at 370 bp, while strains only displaying the 110 bp amplicon were classified as Leclercia pneumoniae. A blind-test on 120 strains accessioned as Enterobacter sp. from the USDA-ARS culture collection (NRRL), revealed that one third of the strains had an incorrect genus assignment. Comparison of gene trees of the hpaBC fragment sequences with marker genes frequently used for single-gene barcoding or multi-locus sequence analysis (MLSA) further demonstrated its potential for preliminary species identification.

    CONCLUSIONS: The nested PCR assay represents a rapid and cost-effective approach for preliminary identification of Enterobacter species. As the primer design was based on large-scale genomic comparison, including currently undescribed species clades, it will remain valid even after taxonomic changes within the genus.

    PMID:40722002 | DOI:10.1186/s12866-025-04175-1

  • Detection of the gummy stem blight pathogens (Stagonosporopsis spp.) in watermelon using field-adapted LAMP assays and rapid DNA extraction protocols 

    Jorge Alberto Reyes Pineda

    Plant Dis. 2025 Aug 6. doi: 10.1094/PDIS-12-24-2589-SR. Online ahead of print.

    ABSTRACT

    Gummy stem blight (GSB), caused by three Stagonosporopsis species, S. citrulli, S. cucurbitacearum and S. caricae, is one of the most economically important diseases hindering watermelon production worldwide. Since there is no commercial resistance to GSB in watermelon cultivars, its management depends on cultural practices and preventative fungicides. Therefore, efficient methods for the detection of Stagonosporopsis species that could aid management decisions are required. To help achieve this, a loop-mediated isothermal amplification (LAMP) assay specific to S. citrulli (SCIT850) was developed under two detection formats: fluorescence quantification and endpoint colorimetric detection. The SCIT850 assay was determined to be specific to its target species and exhibited a consistent sensitivity of 1 pg of genomic DNA under both formats. The assay can be combined with a previously reported LAMP assay for the collective detection of the three Stagonosporopsis spp. (STAGY), which have comparable sensitivity to SCIT850 and can aid in species discrimination. A field diagnostic system for GSB-causing Stagonosporopsis was developed by coupling the SCIT850 and STAGY assays to quick DNA extraction protocols. Two DNA extraction methods were tested: one from leaves using cellulose dipsticks, and one from steel rods (typical of spore traps) using Chelex100. With the dipstick method, we detected pathogen DNA in inoculated asymptomatic, mildly infected, and severely infected plants, while with the Chelex100 we detected pathogen DNA from rods infested with as few as 500 spores. The SCIT850 and STAGY assays coupled with these quick sample processing methods could be adapted for field deployment, which would allow growers to make efficient and timely management decisions based on detection of the actual Stagonosporopsis species present in the field.

    PMID:40767855 | DOI:10.1094/PDIS-12-24-2589-SR

  • Determining the causal agents of Alternaria leaf blight and head rot affecting broccoli in the Eastern United States 

    Roy L Davis

    Plant Dis. 2025 May 22. doi: 10.1094/PDIS-01-25-0117-SR. Online ahead of print.

    ABSTRACT

    Alternaria brassicicola is the causal agent typically associated with Alternaria leaf blight and head rot (ABHR) disease in broccoli and related crops in the Eastern United States. Recently a new species, A. japonica, has been reported as causing disease in broccoli and other vegetables in this region. We conducted a multi-state pathogen survey during the growing seasons of 2022 and 2023 to assess the distribution and occurrence of A. japonica in relation to A. brassicicola in five broccoli-producing states. Our approach specifically targeted collection of broccoli leaves with lesions typical of ABHR within commercially grown fields managed using either organic or conventional approaches in Connecticut, Massachusetts, New York, Virginia, and Georgia. Only typical ABHR leaf lesions were selected for pathogen isolation and, subsequently, sequencing of the Alternaria major allergen a1 gene was used to identify Alternaria species. The predominant species isolated was A. brassicicola (88% in 2022 and 94% in 2023) and the second most common was A. alternata (12% in 2022 and 6% in 2023), which was obtained from fields in Connecticut and Massachusetts in 2022, and in Virginia in both years. Alternaria japonica was not found in either year. Symptoms of A. alternata were indistinguishable from A. brassicicola, as were colony morphologies. While A. alternata is considered a generalist and of little consequence for broccoli, it is considered a pathogen of significance on multiple crops (blueberry, citrus, pistachios), but there remains scant information on the disease etiology on broccoli. Therefore, we inoculated broccoli with A. alternata in controlled conditions in order to shed light on possible differences in infectivity of these species on broccoli. Results of our study showed that A. alternata is pathogenic on broccoli, capable of initiating infection and causing lesions typical of ABHR. This indicates that future disease surveys of ABHR should conclusively identify species of Alternaria that are causing disease. Additional research is needed to determine the significance of this finding in relation to yield impacts, epidemiology, fungicide resistance, and management recommendations.

    PMID:40403277 | DOI:10.1094/PDIS-01-25-0117-SR

  • Discovering leaf and stripe rust resistance in soft red winter wheat through genome-wide association studies 

    John W Bagwell

    Plant Genome. 2025 Jun;18(2):e70055. doi: 10.1002/tpg2.70055.

    ABSTRACT

    Leaf rust (LR) and stripe rust (YR), which are caused by Puccinia triticina and Puccinia striiformis, respectively, are among the most devastating wheat rusts worldwide. These diseases can be managed by using genetically resistant cultivars, an economical and environmentally safer alternative to fungicides. Over 100 and 80 Lr and Yr resistance genes have been discovered, respectively; however, rust pathogens are overcoming introduced resistance genes in the southeastern United States. Genome-wide association study has emerged as a valuable tool to identify new LR and YR resistance loci. In this study, a panel of 263 soft red winter wheat genotypes was evaluated for LR and YR severity in Plains, GA, and Williamson, GA, in a randomized complete block design of two replicates during 2019 and 2021-2023. Also, LR and YR infection types were assessed on seedlings at the three leaf stage in three greenhouse trials. A total of 26 significant quantitative trait loci (QTL) explaining 0.6%-30.8% phenotypic variance (PV) was detected by at least two of the five GAPIT models (BLINK, CMLM, FarmCPU, GLM, and MLM) tested. Nine major QTL included QLrYr-2A.1 linked to single-nucleotide polymorphism S2A_20855466, which had the highest overall PV (30.8%) for response to both rust pathogens in the field. Using the Chinese Spring Reference Genome Version 1.0, we detected 16 candidate genes, and four known R genes and QTL overlapped two major QTL. Of these QTL, 16 are likely novel genetic loci with potential for marker-assisted selection.

    PMID:40495572 | DOI:10.1002/tpg2.70055

  • Discovery of iridoid cyclase completes the iridoid pathway in asterids 

    Maite Colinas

    Nat Plants. 2025 Oct 3. doi: 10.1038/s41477-025-02122-6. Online ahead of print.

    ABSTRACT

    Iridoids are specialized monoterpenes ancestral to asterid flowering plants1,2 that play key roles in defence and are also essential precursors for pharmacologically important alkaloids3,4. The biosynthesis of all iridoids involves the cyclization of the reactive biosynthetic intermediate 8-oxocitronellyl enol. Here, using a variety of approaches including single-nuclei sequencing, we report the discovery of iridoid cyclases from a phylogenetically broad sample of asterid species that synthesize iridoids. We show that these enzymes catalyse formation of 7S-cis-trans and 7R-cis-cis nepetalactol, the two major iridoid stereoisomers found in plants. Our work uncovers a key missing step in the otherwise well-characterized early iridoid biosynthesis pathway in asterids. This discovery unlocks the possibility to generate previously inaccessible iridoid stereoisomers, which will enable metabolic engineering for the sustainable production of valuable iridoid and iridoid-derived compounds.

    PMID:41044409 | DOI:10.1038/s41477-025-02122-6

  • Dr. Diane Okamuro Gather & Grow Webinar

    Gather & Grow Webinar: What is it Like to be a Program Manager at NSF?

    Dr. Diane Okamuro, National Science Foundation Program Manager

    April 17, 2025 | Noon – 1PM

    Join Zoom

     

    Dr. Diane Jofuku Okamuro is a Program Director for the Plant Genome Research Program (PGRP) at the National Science Foundation, Directorate for Biological Sciences (BIO), Division of Integrative Organismal Systems. The PGRP is broad in scope and supports functional genomics tool development and basic discovery research on a genome-wide scale that will provide new insights into plant processes that are important to the U.S. economy. The PGRP Cluster also manages the Plant Genome Research Postdoctoral Fellowships program which is part of the BIO-wide Postdoctoral Research Fellowships in Biology program. In addition, she currently serves on the Working Group for the Biology Integration Institutes (BII) program which supports interdisciplinary, collaborative teams that perform research, education and training on critical questions that span multiple disciplines within and beyond biology.
    Dr. Okamuro received her Ph.D. in Biology from UCLA and is a plant molecular geneticist by training. She has broad-based experience in cutting-edge functional genomics technologies and has held research and management positions in both academia and industry prior to joining NSF in 2005.

  • Dr. Donglin Zhang recently named a 2024 Plant Biotechnology Fellow by the American Society for Horticultural Sciences!

    Congratulations to Dr. Donglin Zhang for recently being named a 2024 Plant Biotechnology Fellow by the American Society for Horticultural Sciences!

    Fellows of the Society are recognized for outstanding contributions to horticulture in one or more of the following areas: research, teaching, administration, or extension on a state, national, and/or international level; exhibition of leadership in horticultural business or industry pertinent to and compatible with the objectives of the Society; and noteworthy contributions to ASHS objectives (“to promote and encourage national and international interest in scientific research and education in horticulture in all its branches”). This may be demonstrated by the nominee’s direct and effective participation in the affairs and activities of the Society (including its Regional Groups) and/or by active involvement in the affairs of other allied organizations having objectives essentially the same as those of ASHS (including international organizations and those in countries other than the United States).

    Election as a Fellow of the Society is the highest honor that ASHS can bestow on its members, in recognition of truly outstanding contributions to horticulture and the Society.

    Congratulations, Dr. Zhang!

  • Dr. Rishi Masalia Gather & Grow Webinar

  • Draft genome assemblies of 38 Aspergillus parasiticus isolates collected from South Georgia crop fields 

    Sunil S Gangurde

    Microbiol Resour Announc. 2025 Sep 12:e0008325. doi: 10.1128/mra.00083-25. Online ahead of print.

    ABSTRACT

    Aspergillus parasiticus is a fungus recognized for producing highly carcinogenic mycotoxins. In this study, we collected 38 isolates of A. parasiticus from fields in South Georgia. We performed whole genome re-sequencing and developed 38 draft genome assemblies of A. parasiticus. The average genome size was 38.7 Mb, with larger genomes (~40 Mb) found in peanut fields in Turner County. Scaffold N50 was recorded highest for isolates collected from the corn fields of Tifton. The average BUSCO completeness score for these assemblies was 99.1%. The genome sequences generated for these 38 isolates will serve as a valuable genomic resource for the community working on aflatoxin mitigation strategies in crops.

    PMID:40938094 | DOI:10.1128/mra.00083-25

  • Drought adaptation index (DAI) based on BLUP as a selection approach for drought-resilient switchgrass germplasm 

    Shiva Om Makaju

    Front Genet. 2025 Aug 25;16:1626083. doi: 10.3389/fgene.2025.1626083. eCollection 2025.

    ABSTRACT

    This study introduces a Drought Adaptation Index (DAI), derived from Best Linear Unbiased Prediction (BLUP), as a method to assess drought resilience in switchgrass (Panicum virgatum L.). A panel of 404 genotypes was evaluated under drought-stressed (CV) and well-watered (UC) conditions over four consecutive years (2019-2022). BLUP-estimated biomass yields were used to calculate the DAI, which enabled classification of genotypes into four adaptation groups: very well-adapted, well-adapted, adapted, and unadapted. The DAI was compared with conventional drought tolerance indices, including the Stress Susceptibility Index (SSI), Stress Tolerance Index (STI), Geometric Mean Productivity (GMP), and Yield Stability Index (YSI). Correlation analyses demonstrated strong agreement between DAI and these indices, supporting its validity and consistency. Biplot analyses using the Genotype plus Genotype-by-Environment Interaction (GGE) and Additive Main Effects and Multiplicative Interaction (AMMI) models revealed significant genotype-by-environment interactions (GEI) and identified J222.A, J463.A, and J295.A. A as high-performing genotypes, with J222.A exhibiting greater yield stability across treatments and years. Additionally, DAI isoline curves provided a graphical representation of differential genotype performance under drought and control conditions. These visualizations aided in distinguishing genotypes with stable and superior biomass yield across contrasting environments. Overall, the BLUP-based DAI is a robust and practical selection tool that improves the accuracy of identifying drought-resilient, high-yielding switchgrass genotypes. Its integration into breeding programs offers a comprehensive framework for improving biomass productivity and stress adaptation under variable climatic conditions. The application of DAI supports the development of climate-resilient cultivars and contributes to sustainable bioenergy and forage production systems.

    PMID:40927363 | PMC:PMC12414770 | DOI:10.3389/fgene.2025.1626083

  • Engineering chromosome number in plants 

    Feng Zhang

    Science. 2025 Nov 20;390(6775):786-787. doi: 10.1126/science.aec7902. Epub 2025 Nov 20.

    ABSTRACT

    Chromosome engineering produces a reduced eight-chromosome karyotype in Arabidopsis thaliana.

    PMID:41264719 | DOI:10.1126/science.aec7902

  • Enzymatic epimerization of monoterpene indole alkaloids in kratom 

    Allwin McDonald

    Nat Chem Biol. 2025 Jul 16. doi: 10.1038/s41589-025-01970-9. Online ahead of print.

    ABSTRACT

    Monoterpene indole alkaloids (MIAs) are a large, structurally diverse class of bioactive natural products. These compounds are biosynthetically derived from a stereoselective Pictet-Spengler condensation that generates a tetrahydro-β-carboline scaffold characterized by a 3S stereocenter. However, a subset of MIAs contains a noncanonical 3R stereocenter. Here we report the basis for 3R-MIA biosynthesis in Mitragyna speciosa (kratom). We discover the presence of the iminium species (20S)-3-dehydrocorynantheidine, which supports isomerization of 3S to 3R via oxidation and stereoselective reduction downstream of the initial Pictet-Spengler condensation. Isotopologue feeding experiments identify the sites for downstream MIA pathway biosynthesis as well as the oxidase/reductase pair that catalyzes this epimerization. This oxidase/reductase pair has broad substrate specificity, suggesting that this pathway may be responsible for the formation of many 3R-MIAs and downstream spirooxindole alkaloids in kratom. The elucidation of this epimerization mechanism allows biocatalytic access to a range of pharmacologically active spirooxindole alkaloid compounds.

    PMID:40670688 | DOI:10.1038/s41589-025-01970-9

  • Estimating Hospitalization Expenditures Associated with Chronic Diseases and Multimorbidity for Older Adults – Guangzhou City, Guangdong Province, China, 2017-2019 

    Fei Zhao

    China CDC Wkly. 2025 Aug 1;7(31):1031-1037. doi: 10.46234/ccdcw2025.175.

    ABSTRACT

    WHAT IS ALREADY KNOWN ABOUT THIS TOPIC?: Chronic diseases and multimorbidity impose substantial burdens on healthcare systems globally, particularly in aging populations, resulting in elevated healthcare utilization rates and increased expenditures.

    WHAT IS ADDED BY THIS REPORT?: This study validates previous research findings using an extensive administrative database from a major city in South China. Additionally, it provides comprehensive estimates of annual hospitalization expenditures per patient associated with chronic diseases and multimorbidity patterns among older adults, elucidating the economic burden and cost variations across specific diseases and multimorbidity combinations. Cancer, cerebrovascular disease (CVD), and heart disease – whether occurring individually or in conjunction with other chronic conditions, particularly within complex multimorbidity patterns – were associated with substantial annual hospitalization expenditures and significant healthcare resource utilization.

    WHAT ARE THE IMPLICATIONS FOR PUBLIC HEALTH PRACTICE?: Disease burden studies provide critical evidence for prioritizing public health policies and targeted interventions. Policymakers should implement comprehensive prevention strategies, evidence-based interventions, appropriate reimbursement policies, and integrated management approaches to control disease progression and reduce healthcare expenditures.

    PMID:40831617 | PMC:PMC12360313 | DOI:10.46234/ccdcw2025.175

  • Ethylene-releasing plant growth regulators promote ripening initiation by stimulating sugar, acid and anthocyanin metabolism in blueberry (Vaccinium ashei) 

    Tej P Acharya

    BMC Plant Biol. 2025 Jun 5;25(1):766. doi: 10.1186/s12870-025-06799-x.

    ABSTRACT

    BACKGROUND: Fruit ripening is a coordinated process that leads to an increase in sugars, decrease in acids and accumulation of pigments. Blueberry fruit exhibit an atypical climacteric ripening behavior. These fruit display an increase in respiration and ethylene production during ripening, however ethylene synthesis is developmentally regulated. In this study, the effect of ethylene on blueberry fruit ripening was investigated via preharvest applications of ethylene-releasing plant growth regulators (PGRs), ethephon and 1-aminocyclopropane 1-carboxylic acid (ACC), in one southern highbush cultivar, Miss Lilly in 2019, and two rabbiteye cultivars, Premier and Powderblue in 2019 and 2020. Further, the effects of these two PGRs on fruit metabolism during ripening in the two rabbiteye cultivars, and postharvest fruit quality in all three cultivars were evaluated.

    RESULTS: Both PGRs increased ethylene evolution within 1-3 days after treatment (DAT). Ethephon and ACC applications increased the rate of ripening within 5 DAT in all cultivars, and increased ripe (blue) fruit by up to 35% and 29%, respectively between 7 to 10 DAT compared to the control. Metabolite analysis revealed that PGR treatments resulted in an immediate, but transient increase in sucrose, glucose and fructose, in ‘Premier’ at 3 DAT. Malate decreased at 3 DAT in response to both PGR treatments in ‘Premier’, and at 5 DAT in ethephon treatment in both cultivars. A rapid increase in the concentration of multiple anthocyanins was noted at 3 DAT in response to both PGRs in ‘Premier’ and ‘Powderblue’. Gene expression analysis revealed an increase in transcript abundance of VACUOLAR INVERTASE (vINV) and multiple anthocyanin biosynthesis genes between 1 and 3 DAT after PGR treatments in both cultivars, supporting the metabolite changes. However, the alteration in fruit metabolite concentrations were not sustained, and similar in PGR-treated fruit compared to the control in ripe fruit harvested at 10 DAT. Postharvest fruit quality attributes, such as firmness, total soluble solids, titratable acidity, and visual quality, were not consistently affected by the PGR applications compared to control treatments across all cultivars. A decrease in fruit weight was noted, although not consistently, in response to PGR treatments.

    CONCLUSIONS: Overall, this study demonstrates that ethylene plays a crucial role in promoting ripening via rapid and transient stimulation of sugar, acid and anthocyanin metabolism. The promotion of fruit ripening by ethylene-releasing PGRs can lead to minimal but inconsistent changes in fruit quality attributes during postharvest storage.

    PMID:40474063 | DOI:10.1186/s12870-025-06799-x

  • Evaporative cooling signals for wound healing in plants 

    Joseph Balem

    bioRxiv [Preprint]. 2025 May 28:2025.05.23.655667. doi: 10.1101/2025.05.23.655667.

    ABSTRACT

    Repairing a damaged body part is critical for the survival of any organism. In plants, tissue damage induces rapid responses that activate defense, regeneration and wound healing. While early wound signaling mediated by phytohormones, electrical signals and reactive oxygen species is well-characterized, the mechanisms governing the final stages of wound healing remain poorly understood. Here, we show that wounding in Arabidopsis leaves induces localized cooling, likely due to evaporative water loss, accompanied by the activation of cold-responsive genes. The subsequent disappearance of localized cooling and deactivation of cold-responsive genes serve as a quantitative marker of wound healing. Based on these observations, we developed a workflow by leveraging computer vision and deep learning to monitor the dynamics of wound healing. We found that CBFs transcription factors relay injury-induced cooling signal to wound healing. Thus, our work advances our understanding of tissue repair and provides a tool to quantify wound healing in plants.

    PMID:40502075 | PMC:PMC12154623 | DOI:10.1101/2025.05.23.655667

  • Everyday norms have become more permissive over time and vary across cultures 

    Kimmo Eriksson

    Commun Psychol. 2025 Oct 7;3(1):145. doi: 10.1038/s44271-025-00324-4.

    ABSTRACT

    Every social situation that people encounter in their daily lives comes with a set of unwritten rules about what behavior is considered appropriate or inappropriate. These everyday norms can vary across societies: some societies may have more permissive norms in general or for certain behaviors, or for certain behaviors in specific situations. In a preregistered survey of 25,422 participants across 90 societies, we map societal differences in 150 everyday norms and show that they can be explained by how societies prioritize individualizing moral foundations such as care and liberty versus binding moral foundations such as purity. Specifically, societies with more individualistic morality tend to have more permissive norms in general (greater liberty) and especially for behaviors deemed vulgar (less purity), but they exhibit less permissive norms for behaviors perceived to have negative consequences in specific situations (greater care). By comparing our data with available data collected twenty years ago, we find a global pattern of change toward more permissive norms overall but less permissive norms for the most vulgar and inconsiderate behaviors. This study explains how social norms vary across behaviors, situations, societies, and time.

    PMID:41057696 | DOI:10.1038/s44271-025-00324-4

  • Factors underlying a latitudinal gradient in the S/G lignin monomer ratio in natural poplar variants 

    Weiwei Zhu

    Proc Natl Acad Sci U S A. 2025 Aug 26;122(34):e2503491122. doi: 10.1073/pnas.2503491122. Epub 2025 Aug 20.

    ABSTRACT

    The chemical composition of wood plays a pivotal role in the adaptability and structural integrity of trees. However, few studies have investigated the environmental factors that determine lignin composition and its biological significance in plants. Here, we examined the lignin syringyl-to-guaiacyl (S/G) ratio in members of a Populus trichocarpa population sourced from their native habitat and conducted a genome wide association study to identify genes linked to lignin formation. Our results revealed many significant associations, suggesting that lignin biosynthesis is a complex polygenic trait. Additionally, we found an increase in the S/G ratio from northern to southern geographic origin of the trees sampled, along with a corresponding metabolic and transcriptional reprogramming of xylem cell wall biosynthesis. Further molecular analysis identified a mutation in a cell wall laccase genetically associated with higher S/G ratios that predominate in trees from warmer lower latitudes. Collectively, our findings suggest that lignin heterogeneity arises from an evolutionary process enabling poplar adaptation to different climatic challenges.

    PMID:40833412 | DOI:10.1073/pnas.2503491122

  • FFAR Announces 26 Awardees of FFAR Fellows Program naming Shreena Pradhan

    WASHINGTON (August 11, 2021) – Climate change, a growing population and evolving pests and pathogens threaten the security of our global food supply. Employers need trained scientists to conduct research that helps farms and food systems adapt to these challenges. The Foundation for Food & Agriculture Research (FFAR) and North Carolina State University are excited to announce the 26 students selected for the 2021 FFAR Fellows Program. This unique three-year program provides professional development training and mentorship to doctoral students conducting research in alignment with FFAR’s six Challenge Areas.

  • FX-Cell: a method for single-cell RNA sequencing on difficult-to-digest and cryopreserved plant samples 

    Xin Ming

    Nat Methods. 2025 Nov 27. doi: 10.1038/s41592-025-02900-2. Online ahead of print.

    ABSTRACT

    Single-cell RNA sequencing in plants requires the isolation of high-quality protoplasts-cells devoid of cell walls. However, many plant tissues and organs are resistant to enzymatic digestion, posing a significant barrier to advancing single-cell multi-omics in plant research. Furthermore, for field-grown crops, the lack of immediate laboratory facilities presents another major challenge for timely protoplast preparation. Here, to address these limitations, we developed FX-Cell and its derivatives, FXcryo-Cell and cryoFX-Cell, to enable single-cell RNA sequencing with both difficult-to-digest and cryopreserved plant samples. By optimizing the fixation buffer and minimizing RNA degradation, our approach ensures efficient cell wall digestion at high temperatures while maintaining high-quality single cells, even after long-term storage at -80 °C, and circumvents use of nuclei, which are not representative of the pool of translatable messenger RNAs. We successfully constructed high-quality cell atlases for rice tiller nodes, rhizomes of wild rice and maize crown roots grown under field conditions. Moreover, these methods enable the accurate reconstruction of plant acute wounding responses at single-cell resolution. Collectively, these advancements expand the applicability of plant single-cell genomics across a wider range of species and tissues, paving the way for comprehensive Plant Cell Atlases for plant species.

    PMID:41310055 | DOI:10.1038/s41592-025-02900-2

  • Gene Expression Differentiation Is Consistent with Local Adaptation across an Elevational Gradient in Drummond’s Rockcress (Boechera stricta) 

    Shelby L Tisinai

    J Hered. 2025 Oct 15:esaf081. doi: 10.1093/jhered/esaf081. Online ahead of print.

    ABSTRACT

    A central goal of evolutionary biology is to understand the mechanisms conferring adaptation. Gene expression is sensitive to environmental variability; thus, investigating gene expression differentiation among populations may reveal signatures of selection from predictable environmental conditions. Environmental pressures that covary with elevation gain (e.g., temperature) result in stark environmental differences along short distances. The phenological and life history traits of plants inhabiting elevational gradients might track these variables, providing an opportunity for testing hypotheses. Boechera stricta occupies a steep elevation gradient in the Rocky Mountains. Here, we grew F3 seeds from at least two genotypes each from five populations of B. stricta in a greenhouse. Analysis of leaf RNAseq data permitted tests of these hypotheses: 1) populations exhibit significant among population genetic variation in gene expression; 2) differentiation in gene expression (QST) exceeds neutral expectations (FST); and 3) the putative functions of differentially expressed genes are predicable based on a priori knowledge of environmental pressures that vary with elevation. Differentiation in gene expression (average QST = 0.53) significantly exceeded neutral differentiation (average FST = 0.17), implicating selection as a potential cause of genetically divergent patterns of gene expression. The putative functions of differentially expressed genes covarying with elevation were enriched for biological processes related to conditions that vary with elevation (circadian rhythm, response to light, chloroplast organization, and vegetative to reproductive meristem transitions). This study reveals considerable differentiation in gene expression, which may provide a mechanism for rapid adaptation to local environmental conditions in this and other species.

    PMID:41092278 | DOI:10.1093/jhered/esaf081

  • Genetic and environmental influences on the distributions of three chromosomal drive haplotypes in maize 

    Meghan J Brady

    bioRxiv [Preprint]. 2025 May 27:2025.05.22.655462. doi: 10.1101/2025.05.22.655462.

    ABSTRACT

    Meiotic drive elements are regions of the genome that are transmitted to progeny at frequencies that exceed Mendelian expectations, often to the detriment of the organism. In maize there are three prevalent chromosomal drive elements known as Abnormal chromosome 10 (Ab10), K10L2, and the B chromosome. There has been much speculation about how these drivers might interact with each other and the environment in traditional maize landraces and their teosinte ancestors. Here we used genotype-by-sequencing data to score more than 10,000 maize and teosinte lines for the presence or absence of each driver. Less than ~0.5% of modern inbred lines carry chromosomal drivers. Among individuals from 5331 open-pollinated landraces, 6.32% carried Ab10, 5.16% carried K10L2, and 12.28% carried at least one B chromosome. Using a GWAS approach we identified unlinked loci that associate with the presence or absence of the selfish genetic elements. Many genetic modifiers are positively associated with the drivers, suggesting that there may have been selection for alleles that ameliorate their negative fitness consequences. We then assessed the contributions of population structure, associated loci, and the environment on the distribution of each chromosomal driver. There was no significant relationship between any chromosomal driver and altitude, contrary to conclusions based on smaller studies. Our data suggest that the distribution of the major chromosomal drivers is primarily influenced by neutral processes and the deleterious fitness consequences of the drivers themselves. While each driver has a unique relationship to genetic background and the environment, they are largely unconstrained by either.

    PMID:40501570 | PMC:PMC12154789 | DOI:10.1101/2025.05.22.655462

2020 Cohort

  • 1H-NMR Guided Isolation of Bioactive Compounds from Species of the Genus Piper 

    Author: Ian S Wallace 

    Molecules. 2025 Apr 30;30(9):2020. doi: 10.3390/molecules30092020.

    ABSTRACT

    The discovery of bioactive natural products is often challenged by the complexity of isolating and characterizing active compounds within diverse mixtures. Previously, we introduced a 1H NMR-based weighted gene correlation network analysis (WGCNA) approach to identify spectral features linked to growth inhibitory activity of Piper (Piperaceae) leaf extracts against model plant, fungal, and bacterial organisms. This method enabled us to prioritize specific spectral features linked to bioactivity, offering a targeted approach to natural product discovery. In this study, we validate the predictive capacity of the WGCNA by isolating the compounds responsible for the bioactivity-associated resonances and confirming their antifungal efficacy. Using growth inhibition assays, we verified that the isolated compounds, including three novel antifungal agents, exhibited significant bioactivity. Notably, one of these compounds contains a rare imidazolium heterocyclic motif, marking a new structural class in Piper. These findings substantiate the 1H NMR-based WGCNA as a reliable tool for identifying structural types associated with biological activity, streamlining the process of discovering bioactive natural products in complex extracts.

    PMID:40363825 | PMC:PMC12073215 | DOI:10.3390/molecules30092020

  • 2023 Retreat Agenda

  • 2025 Spring Symposium Save the Date

  • 35th E. S. Luttrell Lecture

  • A Case Study for Visual Detection of a Systemic Disease: Optimizing Identification of Phony Peach Disease Based on Statistical and Machine Learning Models 

    Weiqi Luo

    Phytopathology. 2025 Jun 22. doi: 10.1094/PHYTO-03-25-0093-R. Online ahead of print.

    ABSTRACT

    Phony peach disease (PPD), caused by Xylella fastidiosa subsp. multiplex (Xfm), poses a significant threat to commercial peach orchards in Georgia. Early and accurate detection is essential for effective disease management, yet visual assessment remains the primary approach for diagnosing PPD symptoms due to the high cost and logistical challenges of qPCR-based detection of Xfm. We evaluated the accuracy of visual PPD assessment and examined the factors influencing rater performance, symptom reliability, and optimal survey deployment strategies with CART/Random Forest analyses and simulations. Internode length was the most reliable symptom for PPD identification in two peach cultivars, consistently outperforming other physical traits such as canopy flatness and shape. Primer pair C06Xf-bamA had the greatest relative sensitivity, making it the preferred choice for qPCR confirmation. Principal component analysis suggested that rater experience significantly improved agreement with qPCR results and repeated assessments of the same orchards further enhanced consistency for raters. Simulations results suggested that deploying two experienced raters may provide the highest detection diagnostic accuracy for survey purposes, particularly when qPCR-based pathogen detection is unavailable. Last, PPD-affected trees, through PCR verification and visual identification, exhibited higher mortality rates than Xfm-negative trees, reinforcing the need for early detection and removal to limit disease spread. These findings underscore the importance of strategic rater deployment, targeted symptom selection, and integrating molecular diagnostics when feasible.

    PMID:40544457 | DOI:10.1094/PHYTO-03-25-0093-R

  • A cell-type-specific regulon controlling monoterpene indole alkaloid biosynthesis with feedback and feedforward activation loops 

    Chenxin Li

    New Phytol. 2025 Nov 9. doi: 10.1111/nph.70712. Online ahead of print.

    ABSTRACT

    Monoterpene indole alkaloids (MIA) are a diverse class of plant natural products produced by a subset of lineages within the Asterid clade of eudicots. The diversity of MIAs provides a unique opportunity to study not only the evolution of biosynthetic genes but also their regulation. In this study, we investigate the cell type specificity of biosynthetic genes and coexpressed transcription factors (TFs) in two MIA-producing Asterid species, Catharanthus roseus, a well-studied MIA-producing species, and Camptotheca acuminata, which belongs to an early-diverging lineage of the Asterid clade. We generated single-cell RNA-seq data from the C. acuminata stem, the primary site of camptothecin biosynthesis. We found that MIA biosynthetic genes in C. acuminata are specific to exceptionally rare cell populations. We discovered MYB and bHLH TFs coexpressed in the same cell types as MIA biosynthetic genes in the C. acuminata stem. Interestingly, the C. roseus orthologs of these TFs are idioblast-specific and activate MIA biosynthetic genes in C. roseus upon overexpression. We constructed an extended gene regulatory network for the idioblast metabolic regulon in C. roseus, which contains both feedback and feedforward activation loops. This study demonstrates co-option of the same clades of TFs for regulation of cell-type-specific MIA biosynthesis across two Asterid species separated by c. 115 million years of evolution. Investigating cell-type-specific TFs that are coexpressed with biosynthetic genes across multiple species is a powerful strategy to increase the power for the discovery of plant metabolic regulators.

    PMID:41208325 | DOI:10.1111/nph.70712

  • A compendium of nonredundant short polymerase III promoters for CRISPR applications 

    Michihito Deguchi

    Plant Physiol. 2025 Jul 3;198(3):kiaf294. doi: 10.1093/plphys/kiaf294.

    ABSTRACT

    Minimal native and synthetic Polymerase III promoters enable efficient and customizable CRISPR multiplexing in plants, expanding genome engineering capabilities

    PMID:40673482 | PMC:PMC12268498 | DOI:10.1093/plphys/kiaf294

  • A global dataset of terrestrial biological nitrogen fixation 

    Carla R Reis Ely

    Sci Data. 2025 Aug 5;12(1):1362. doi: 10.1038/s41597-025-05131-4.

    ABSTRACT

    Biological nitrogen fixation (BNF) is the main natural source of new nitrogen inputs in terrestrial ecosystems, supporting terrestrial productivity, carbon uptake, and other Earth system processes. We assembled a comprehensive global dataset of field measurements of BNF in all major N-fixing niches across natural terrestrial biomes derived from the analysis of 376 BNF studies. The dataset comprises 32 variables, including site location, biome type, N-fixing niche, sampling year, quantification method, BNF rate (kg N ha-1 y-1), the percentage of nitrogen derived from the atmosphere (%Ndfa), N fixer or N-fixing substrate abundance, BNF rate per unit of N fixer abundance, and species identity. Overall, the dataset combines 1,207 BNF rates for trees, shrubs, herbs, soil, leaf litter, woody litter, dead wood, mosses, lichens, and biocrusts, 152 herb %Ndfa values, 1,005 measurements of N fixer or N-fixing substrate abundance, and 762 BNF rates per unit of N fixer abundance for a total of 424 species across 66 countries. This dataset facilitates synthesis, meta-analysis, upscaling, and model benchmarking of BNF fluxes at multiple spatial scales.

    PMID:40764484 | DOI:10.1038/s41597-025-05131-4

  • A high-quality genome assembly of the tetraploid Teucrium chamaedrys unveils a recent whole genome duplication and a large biosynthetic gene cluster for diterpenoid metabolism 

    Abigail E Bryson

    Plant Commun. 2025 Jun 3:101393. doi: 10.1016/j.xplc.2025.101393. Online ahead of print.

    ABSTRACT

    Teucrium chamaedrys, also called wall germander, is a small woody shrub native to the Mediterranean region. Its name is derived from the Greek words meaning ‘ground oak’, since its tiny leaves resemble those of an oak tree. Teucrium species are proliferative producers of diterpenes, which afford them valuable properties widely co-opted in traditional and western medicines. Sequence and assembly of the 3 Gbp tetraploid T. chamaedrys revealed 74 diterpene synthase genes, with the vast representation of these diterpene synthases clustered along four genomic loci. Comparative genomics revealed that this cluster is mirrored in the closely related species, Teucrium marum. Along with the presence of several cytochrome p450 sequences, this region is the one of largest biosynthetic gene clusters identified. Teucrium is well known for accumulating clerodane-type diterpenoids which are produced from a kolavanyl diphosphate precursor. To elucidate the complex biosynthetic pathways of these medicinal compounds, we identified and functionally characterized several kolavanyl diphosphate synthases from T. chamaedrys. Its remarkable chemistry and tetraploidy make T. chamaedrys an interesting and unique model for studying genomic evolution and adaptation in plants.

    PMID:40468595 | DOI:10.1016/j.xplc.2025.101393

  • A nitric oxide reductase is a key enzyme target for eliminating fungal emissions of nitrous oxide 

    Blake A Oakley

    Fungal Genet Biol. 2025 Sep 23:104038. doi: 10.1016/j.fgb.2025.104038. Online ahead of print.

    ABSTRACT

    Nitrous oxide (N2O) derived from agricultural activity is a major contributor to Earth’s greenhouse effect. Synthetic nitrogen fertilizer applied at high levels, particularly combined with heavy rainfall events, generates hot spots of N2O emissions in agricultural fields due to the process of microbial denitrification. Here, a key conserved fungal denitrification enzyme necessary for N2O emissions was identified. Phylogenetic analysis revealed that fungal NOR1-like genes, with rare exceptions, are highly conserved and confined to the phylum Ascomycota. Plant pathogenic Fusarium species that possess NOR1 exhibited drastic differences in N2O production based on denitrification potential. Functional characterization of the p450nor nitric oxide reductase encoding gene, NOR1, in the soil-borne denitrifying maize pathogen, Fusarium verticillioides, showed that this enzyme is critical for fungal N2O production. Deletion of the single copy NOR1 gene in F. verticillioides eliminated N2O emissions. Complementation of deletion mutants via the NOR1 gene add-back restored wild type N2O emission levels and segregation analysis further corroborated the pivotal role of NOR1 for N2O emissions. We suggest targeting of the NOR1 enzyme as an effective strategy to reduce fungal-based N2O emissions.

    PMID:40998212 | DOI:10.1016/j.fgb.2025.104038

  • Aerial root formation in Oaxacan maize (Zea mays) landraces persists into the adult phase and is minimally affected by soil nitrogen and ambient humidity 

    Rafael E Venado

    Front Plant Sci. 2025 Jul 11;16:1607733. doi: 10.3389/fpls.2025.1607733. eCollection 2025.

    ABSTRACT

    Maize (Zea mays L.) is the most widely produced crop in the world, and conventional production requires significant amounts of synthetic nitrogen fertilizer, which has negative economic and environmental consequences. Maize landraces from Oaxaca, Mexico, can acquire nitrogen from nitrogen-fixing bacteria that live in a mucilage secreted by aerial nodal roots. The development of these nodal roots is a characteristic traditionally associated with the juvenile vegetative stage of maize plants. However, mature Oaxacan landraces develop many more nodes with aerial roots than commercial maize varieties. Our study shows that Oaxacan landraces develop aerial roots during the juvenile and adult vegetative phases and even during early flowering under greenhouse and field conditions. Surprisingly, the development of these roots was only minimally affected by soil nitrogen and ambient humidity. These findings are an essential first step in developing maize varieties to reduce fertilizer needs in maize production across different environmental conditions.

    PMID:40718026 | PMC:PMC12289584 | DOI:10.3389/fpls.2025.1607733

  • An updated sulfate transporter phylogeny uncovers a perennial-specific subgroup associated with lignification 

    Samantha M Surber

    Tree Physiol. 2025 Jul 11:tpaf080. doi: 10.1093/treephys/tpaf080. Online ahead of print.

    ABSTRACT

    Sulfate-proton co-transporters (SULTRs) mediate sulfate uptake, transport, storage, and assimilation in plants. The SULTR family has historically been classified into four groups (SULTR1-SULTR4), with well-characterized roles for SULTR groups 1, 2, and 4. However, the functions of the large and diverse SULTR3 group remain poorly understood. Here, we present an updated phylogenetic analysis of SULTRs across angiosperms, including multiple early-divergent lineages. Our results suggest that the enigmatic SULTR3 group comprises four distinct subfamilies that predate the emergence of angiosperms, providing a basis for reclassifying the SULTR family into seven subfamilies. This expanded classification is supported by subfamily-specific gene structures and amino acid substitutions in the substrate-binding pocket. Structural modeling identified three serine residues uniquely lining the substrate-binding pocket of SULTR3.4, enabling three hydrogen bonds with the phosphate ion. The data support the proposed neofunctionalization of this subfamily for phosphate allocation within vascular tissues. Transcriptome analysis of Populus tremula × alba revealed divergent tissue expression preferences among SULTR subfamilies and between genome duplicates. We observed partitioned expression in vascular tissues among the four SULTR3 subfamilies, with PtaSULTR3.4a and PtaSULTR3.2a preferentially expressed in primary and secondary xylem, respectively. Gene coexpression analysis revealed coordinated expression of PtaSULTR3.4a with genes involved in phosphate starvation responses and nutrient transport, consistent with a potential role in phosphate homeostasis. In contrast, PtaSULTR3.2a was strongly coexpressed with lignification and one-carbon metabolism genes and their upstream transcription regulators. PtaSULTR3.2a belongs to a eudicot-specific branch of the SULTR3.1 subfamily found only in perennial species, suggesting a specialized role in lignifying tissues. Together, our findings provide a refined phylogenetic framework for the SULTR family and suggest that the expanded SULTR3 subfamilies have undergone neofunctionalization during the evolution of vascular and perennial plants.

    PMID:40643194 | DOI:10.1093/treephys/tpaf080

  • Anionic lipids direct efficient microfluidic encapsulation of stable and functionally active proteins in lipid nanoparticles 

    Suresh Ambati

    Commun Mater. 2025;6(1):34. doi: 10.1038/s43246-025-00749-8. Epub 2025 Feb 22.

    ABSTRACT

    Because proteins do not efficiently pass through the plasma membrane, protein therapeutics are limited to target ligands located at the cell surface or in serum. Lipid nanoparticles can facilitate delivery of polar molecules across a membrane. We hypothesized that because most proteins are amphoteric ionizable polycations, proteins would associate with anionic lipids, enabling microfluidic chip assembly of stable EP-LNPs (Encapsulated Proteins in Lipid NanoParticles). Here, by employing anionic lipids we were able to efficiently load proteins into EP-LNPs at protein:lipid w:w ratios of 1:20. Several proteins with diverse molecular weights and isoelectric points were encapsulated at efficiencies of 70 75%-90% and remained packaged for several months. Proteins packaged in EP-LNPs efficiently entered mammalian cells and fungal cells with cell walls. The proteins delivered intracellularly were functional. EP-LNPs technology should improve cellular delivery of medicinal antibodies, enzymes, peptide antimetabolites, and dominant negative proteins, opening new fields of protein therapeutics.

    PMID:41146908 | PMC:PMC12553553 | DOI:10.1038/s43246-025-00749-8

  • Anne Frances Jarrell wins 1st Place at the NAPB 2023 Poster Competition!

    Anne Frances Jarrell from the 2021 Cohort won first place for the PhD Poster Competition at the 2023 National Association of Plant Breeders meeting!

    In Spring 2022, Anne Frances officially joined the Robin Buell lab as a Graduate Research Assistant. She is interested in using advances in genomics to improve crop breeding, specifically to increase sustainability and crop resiliency in the face of global climate change. Currently, this leads her to work with potatoes and their wild relatives.

    Learn more about Anne Frances and her work by visiting the Buell Lab website!

    Congratulations Anne Frances!

  • Assessing UV-C radiation treatments for dollar spot suppression in seashore paspalum 

    Willis Turner Spratling

    Plant Dis. 2025 Dec 8. doi: 10.1094/PDIS-08-24-1610-RE. Online ahead of print.

    ABSTRACT

    Dollar spot, caused by Clarireedia spp., is one of the most detrimental diseases of turfgrass worldwide, and control strategies usually involve frequent fungicide applications. These treatments are expensive, require special equipment and can contribute to fungicide resistance issues, underscoring the need for alternative management strategies. UV-C radiation has proven effective as a disease management tool in various cropping systems but is still largely unexplored in turfgrass. This study aimed to test the effects of UV-C radiation against dollar spot in seashore paspalum and to evaluate its impact on plant health and performance. In assessing UV-C’s efficacy directly against C. monteithiana, daily radiation treatments ranging from 27.5 J m-2 to 77.0 J m-2 were shown to effectively reduce mycelial growth. Additionally, in vitro UV-C treatment administered in darkness was observed to be more effective in reducing pathogen growth than treatment administered in lighted conditions. In a growth chamber setting, daily 66.0 J m-2 UV-C treatment significantly reduced dollar spot severity in seashore paspalum without causing phytotoxic damage to plant tissues. In field trials, a novel UV-C application system was implemented by modifying a robotic mower to autonomously deliver UV-C radiation to seashore paspalum plots. UV-C treatment in the field significantly reduced dollar spot severity. Moreover, UV-C treatment led to several physiological and performance enhancements, including increased chlorophyll content, shoot density, surface firmness, and green speed. Findings from this study indicate that UV-C radiation may be used as an effective physical control to complement existing dollar spot management practices.

    PMID:41362131 | DOI:10.1094/PDIS-08-24-1610-RE

  • Biology, Ecology, and Management of Prevalent Thrips Species (Thysanoptera: Thripidae) Impacting Blueberry Production in the Southeastern United States 

    Rosan Adhikari

    Insects. 2025 Jun 24;16(7):653. doi: 10.3390/insects16070653.

    ABSTRACT

    Blueberry is a high-value fruit crop in the United States, with Georgia and Florida serving as important early-season production regions. In these areas, several thrips species (Thysanoptera: Thripidae), including Frankliniella tritici (Fitch), Frankliniella bispinosa (Morgan), and Scirtothrips dorsalis (Hood), have emerged as economically significant pests. While F. tritici and F. bispinosa primarily damage floral tissues, S. dorsalis targets young foliage. Their rapid reproduction, high mobility, and broad host range contribute to rapid population buildup and complicate the management programs. Species identification is often difficult due to overlapping morphological features and requires the use of molecular diagnostic tools for accurate identification. Although action thresholds, such as 2-6 F. tritici per flower cluster, are used to guide management decisions, robust economic thresholds based on yield loss remain undeveloped. Integrated pest management (IPM) practices include regular monitoring, cultural control (e.g., pruning, reflective mulch), biological control using Orius insidiosus (Say) and predatory mites, and chemical control. Reduced-risk insecticides like spinetoram and spinosad offer effective suppression while minimizing harm to pollinators and beneficial insects. However, the brief flowering period limits the establishment of biological control agents. Developing species-specific economic thresholds and phenology-based IPM strategies is critical for effective and sustainable thrips management in blueberry cropping systems.

    PMID:40725285 | DOI:10.3390/insects16070653

  • Bordetellae colonization oligosaccharide (b-Cool), a glycan crucial for nasal colonization 

    Yang Su

    Sci Adv. 2025 Sep 5;11(36):eadw7764. doi: 10.1126/sciadv.adw7764. Epub 2025 Sep 3.

    ABSTRACT

    Respiratory tract infections pose considerable global health challenges. Upper airway colonization is pivotal to these infections, including those caused by Bordetella species. We identified an oligosaccharide, bordetellae colonization oligosaccharide (b-Cool), crucial for early nasal colonization of Bordetella bronchiseptica. We characterized the structure of b-Cool by LC-MS and NMR and found that it is prevalent across a diverse range of bordetellae, including Bordetella pertussis, which causes whooping cough in humans. A B. bronchiseptica mutant lacking b-Cool (Δb-Cool) showed significantly delayed and decreased colonization in mouse nasopharynx and nasal epithelia, resulting in decreased transmission. The colonization defect of Δb-Cool was rescued in mucin deficient mice, suggesting that b-Cool may facilitate colonization in the presence of airway mucins.

    PMID:40901963 | DOI:10.1126/sciadv.adw7764

  • Building an expanded bio-based economy through synthetic biology 

    Andrea M Garza Elizondo

    Biotechnol Adv. 2025 Dec 6:108775. doi: 10.1016/j.biotechadv.2025.108775. Online ahead of print.

    ABSTRACT

    The field of synthetic biology is essential to the continued development of a bio-based economy, creating mechanisms to supply carbon needed in the economy by both converting existing end-of-life wastes as well as by creating novel, purpose-grown and sustainable feedstocks. Here, we first discuss the near- and long-term resources available for use as feedstocks for bioconversion as well as the output molecules needed for building the foundation of an expanded bio-based economy. We then outline the organisms and phenotypic traits that are needed for the performance-advantaged chassis organisms of the future. Furthermore, we detail the advances, challenges, and opportunities in both microbial and plant synthetic biology relevant to expanding the bio-based economy. Finally, we explore technologies that have and will further enable advances in synthetic biology and the greater bio-based economy.

    PMID:41360191 | DOI:10.1016/j.biotechadv.2025.108775

  • Building genomic resources to facilitate the study and use of Solanum microdontum, a wild relative of cultivated potato 

    Anne Frances Jarrell

    G3 (Bethesda). 2025 Oct 23:jkaf253. doi: 10.1093/g3journal/jkaf253. Online ahead of print.

    ABSTRACT

    Solanum microdontum Bitter is a diploid wild Andean relative of potato that has shaped the domestication and adaptation of modern cultivated potato to diverse environments. Solanum microdontum has the potential to provide a wealth of untapped genetic material for use in addressing current challenges in potato breeding. Here, we report a high-quality 772 Mb reference genome sequence for S. microdontum that is anchored to 12 chromosomes. The resulting genome assembly has 99.0% complete Benchmarking Universal Single Copy Orthologs and an N50 scaffold length of over 57 Mb, indicating a high level of completeness. Annotation of the assembly resulted in the identification of 37,324 protein coding genes and 65% repetitive sequence. A total of 1,187 nucleotide-binding leucine-rich repeat genes were predicted from the assembly, of which 93.1% overlapped an annotated high-confidence gene model. A k-mer based kinship matrix derived from a 107-member S. microdontum diversity panel revealed an underlying population structure that corresponds to geographic proximity. The S. microdontum dataset enhances publicly available potato genome resources by providing breeders with genetic, molecular, and germplasm resources for newly developed diploid potato breeding programs.

    PMID:41128648 | DOI:10.1093/g3journal/jkaf253

  • Candidate genes at the Rmi1 locus for resistance to Meloidogyne incognita in soybean 

    Kelly Goode

    Theor Appl Genet. 2025 Oct 29;138(11):286. doi: 10.1007/s00122-025-05065-w.

    ABSTRACT

    The RKN resistance locus Rmi1 was fine-mapped to two genes on chromosome 10, a glycosyl hydrolase family 9 β-1,4-endoglucanase gene and a type I pectin methylesterase gene. Root-knot nematodes (Meloidogyne spp.) are a serious threat to soybean production in the southeast USA, with yield losses of more than $165 million in 2023. Development and deployment of resistant soybean cultivars is the most effective strategy for managing these nematode pests; however, the identity of the resistance genes and underlying mechanism of resistance remains obscure. An additive resistance gene, Resistance to M. incognita-1 (Rmi1), to the predominant species, was first identified in soybean cultivar Forrest but never mapped to a genomic region. Multiple mapping studies have identified a major quantitative trait locus (QTL) with additive action on chromosome 10. In this study, a population consisting of 170 F2:3 families derived from a cross of Bossier (susceptible) × Forrest (resistant) was initially used to confirm that Rmi1 is in the chromosome 10 QTL. Subsequently, 884 F5:6 recombinant inbred lines (RILs) derived from the same cross were used to fine-map the Rmi1 causal gene(s) to two genes – a β-1,4-endoglucanase (Glyma.10G017000, EG) and a pectin methylesterase/methylesterase inhibitor (Glyma.10G017100, PME1). Both gene candidates have the potential to play a role in the resistance response to M. incognita. Both gene promoters harbor SNPs and indels and the encoded proteins exhibit amino acid polymorphisms, including a premature stop in PME1 of resistant soybeans. Additionally, both genes show a higher expression level in susceptible roots compared to resistant roots in the absence of infection. This suggests that Rmi1 may confer one or more pre-existing differences related to cell wall modification in soybean roots, ultimately leading to a decrease in susceptibility.

    PMID:41160124 | DOI:10.1007/s00122-025-05065-w

  • Celebrating the fifth edition of the International Symposium on Fungal Stress – ISFUS, a decade after its 2014 debut 

    Alene Alder-Rangel

    Fungal Biol. 2025 Aug;129(5):101590. doi: 10.1016/j.funbio.2025.101590. Epub 2025 May 6.

    ABSTRACT

    The Fifth International Symposium on Fungal Stress (ISFUS) brought together in Brazil many of the leaders in the field of fungal stress responses, from fourteen countries, for four days of outstanding science ranging from basic research to studies with agricultural, medical, industrial, and environmental significance. In addition to the excellent oral and poster presentations, the Symposium organisers ensured that all participants had ample opportunity to engage, socialise, and network to exchange ideas and share research. The conference was enhanced by the world-class venue near Iguazu Falls, probably the greatest natural phenomenon in South America.

    PMID:40707112 | DOI:10.1016/j.funbio.2025.101590

  • Characterization of Pseudomonas alliivorans strains isolated from Georgia, USA: insights into genomic diversity and pathogenicity in onions 

    Mei Zhao

    Appl Environ Microbiol. 2025 Nov 25:e0164325. doi: 10.1128/aem.01643-25. Online ahead of print.

    ABSTRACT

    Pseudomonas alliivorans is an important emerging pathogen affecting numerous crops. The species is closely related to Pseudomonas viridiflava, with which P. alliivorans strains were often misidentified in the past. Here, we investigated the genetic and pathogenic characteristics of P. alliivorans strains isolated primarily from onions and weeds in Georgia, USA, using whole-genome sequencing, comparative genomics, and functional assays. We delineated the core genome and genetic diversity of these isolates, assessed their pathogenicity on onion foliage and red onion scales, and examined the roles of key virulence determinants (Hrp1-type III secretion system [T3SS], rhizobium-T3SS, type II secretion systems [T2SSs], and thiosulfinate [allicin]-tolerance alt cluster). Our results showed that the Hrp1-T3SS is pivotal for pathogenicity in P. alliivorans, whereas the rhizobium-T3SS, T2SSs, and alt cluster do not contribute to symptom development on red onion scales. Notably, the alt cluster confers in vitro thiosulfinate tolerance, supporting bacterial survival against onion-derived antimicrobial compounds. Additionally, homologous recombination in P. alliivorans occurs infrequently (at approximately one-tenth the rate of point mutations) and involves divergent DNA segments. The alt cluster is acquired through horizontal gene transfer, as evidenced by its lower GC content and the presence of adjacent transposases. In summary, our research provides valuable insights into the genetic diversity, evolutionary dynamics, and virulence mechanisms of P. alliivorans strains from Georgia, USA.IMPORTANCEPseudomonas alliivorans is an emerging plant pathogen that threatens onion and other plants of economic importance. This study identifies key traits that help this bacterium cause disease, such as a specific secretion system critical for infecting onions, and a gene cluster that aids bacterial survival in onion tissues. Beyond highlighting weed as a potential inoculum source and supporting better weed management, the findings of this research open avenues for more targeted disease menegement. By unraveling the genetics of this pathogen, we can develop improved ways to detect, prevent, and reduce its impact, protecting crop health and yields.

    PMID:41288358 | DOI:10.1128/aem.01643-25

  • Comparative Analyses of Four Reference Genomes Reveal Exceptional Diversity and Weak Linked Selection in the Yellow Monkeyflower (Mimulus guttatus) Complex 

    John T Lovell

    Mol Ecol Resour. 2025 Jul 22:e70012. doi: 10.1111/1755-0998.70012. Online ahead of print.

    ABSTRACT

    Yellow monkeyflowers (Mimulus guttatus complex, Phrymaceae) are a powerful system for studying ecological adaptation, reproductive variation, and genome evolution. To initiate pan-genomics in this group, we present four chromosome-scale assemblies and annotations of accessions spanning a broad evolutionary spectrum: two from a single M. guttatus population, one from the closely related selfing species M. nasutus, and one from a more divergent species M. tilingii. All assemblies are highly complete and resolve centromeric and repetitive regions. Comparative analyses reveal such extensive structural variation in repeat-rich, gene-poor regions that large portions of the genome are unalignable across accessions. As a result, this Mimulus pan-genome is primarily informative in genic regions, underscoring limitations of resequencing approaches in such polymorphic taxa. We document gene presence-absence, investigate the recombination landscape using high-resolution linkage data, and quantify nucleotide diversity. Surprisingly, pairwise differences at fourfold synonymous sites are exceptionally high-even in regions of very low recombination-reaching ~3.2% within a single M. guttatus population, ~7% within the interfertile M. guttatus species complex (approximately equal to SNP divergence between great apes and Old World monkeys), and ~7.4% between that complex and the reproductively isolated M. tilingii. Genome-wide patterns of nucleotide variation show little evidence of linked selection, and instead suggest that the concentration of genes (and likely selected sites) in high-recombination regions may buffer diversity loss. These assemblies, annotations, and comparative analyses provide a robust genomic foundation for Mimulus research and offer new insights into the interplay of recombination, structural variation, and molecular evolution in highly diverse plant genomes.

    PMID:40693537 | DOI:10.1111/1755-0998.70012

  • Comparative Transcriptomic Analysis of Soybean Recombinant Inbred Lines Differing at the Rmi1 Locus for Resistance to Meloidogyne incognita During Early Stages of Nematode Infection 

    Kelly Goode

    Phytopathology. 2025 Jun 11. doi: 10.1094/PHYTO-04-25-0143-SC. Online ahead of print.

    ABSTRACT

    Root-knot nematodes (Meloidogyne spp.) are a continuing threat to soybean production, with M. incognita being the predominant species. The deployment of Mi-resistant soybean cultivars is a primary management strategy, but the underlying molecular mechanisms contributing to resistance remain unknown. A single, additive gene for resistance to M. incognita, Rmi1, was previously identified in soybean cv. Forrest and associated with the emigration of second-stage juveniles from the roots. To better understand the Rmi1-mediated resistance response, we used Forrest-derived F5 RILs differing for Rmi1 to analyze global changes in gene expression in response to M. incognita infection at 2- and 4-days post inoculation. We identified 1,471 differentially expressed (DE) genes in the compatible interaction and 1,037 DE genes in the incompatible interaction. Forty-five percent of DE genes were DE in both interactions, 42% (856) were unique to the compatible interaction, and 13% (261) were unique to the incompatible interaction. Genes uniquely DE in the incompatible interaction included genes involved in cell wall modification, hormone signaling, endomembrane trafficking, and redox reactions providing new insights into the resistance mechanism mediated by Rmi1 in soybean to root-knot nematodes.

    PMID:40498525 | DOI:10.1094/PHYTO-04-25-0143-SC

  • Conflicting kinesin-14s in a single chromosomal drive haplotype 

    Author: Kelly Dawe

    Genetics. 2025 May 14:iyaf091. doi: 10.1093/genetics/iyaf091. Online ahead of print.

    ABSTRACT

    In maize, there are two meiotic drive systems that target large heterochromatic knobs composed of tandem repeats known as knob180 and TR-1. The first meiotic drive haplotype, Abnormal chromosome 10 (Ab10) confers strong meiotic drive (∼75% transmission as a heterozygote) and encodes two kinesins: KINDR, which associates with knob180 repeats and TRKIN, which associates with TR-1 repeats. Prior data show that meiotic drive is conferred primarily by the KINDR/knob180 system while the TRKIN/TR-1 system seems to have little or no role, making it unclear why Trkin has been maintained in Ab10 haplotypes. The second meiotic drive haplotype, K10L2, confers a low level of meiotic drive (∼51-52%) and only encodes the TRKIN/TR-1 system. Here we used long-read sequencing to assemble the K10L2 haplotype and showed that it has strong homology to an internal portion of the Ab10 haplotype. We also carried out CRISPR mutagenesis to test the role of Trkin on Ab10 and K10L2. The data indicate that the Trkin gene on Ab10 does not improve drive or fitness but instead has a weak deleterious effect when paired with a normal chromosome 10. The deleterious effect is more severe when Ab10 is paired with K10L2: in this context functional Trkin on either chromosome nearly abolishes Ab10 drive. Mathematical modeling based on the empirical data suggest that Trkin is unlikely to persist on Ab10. We conclude that Trkin either confers an advantage to Ab10 in untested circumstances or that it is in the process of being purged from the Ab10 population.

    PMID:40365704 | DOI:10.1093/genetics/iyaf091

  • Correction: Drought adaptation index (DAI) based on BLUP as a selection approach for drought-resilient switchgrass germplasm 

    Shiva Om Makaju

    Front Genet. 2025 Nov 12;16:1731825. doi: 10.3389/fgene.2025.1731825. eCollection 2025.

    ABSTRACT

    [This corrects the article DOI: 10.3389/fgene.2025.1626083.].

    PMID:41311856 | PMC:PMC12648043 | DOI:10.3389/fgene.2025.1731825

  • Cross-resistance in Alternaria brassicicola from naturally infested broccoli seeds against two succinate dehydrogenase inhibitor fungicides 

    Navjot Kaur

    Appl Environ Microbiol. 2025 Sep 4:e0108325. doi: 10.1128/aem.01083-25. Online ahead of print.

    ABSTRACT

    Seeds can serve as a vehicle for the dissemination of pests and pathogens around the world. We recently demonstrated the association of pathogenic Alternaria brassicicola isolates with reduced sensitivity to azoxystrobin (quinone-outside inhibitor [QoI]) in naturally infested commercial broccoli seeds. In this study, we further demonstrate that these isolates were also resistant to two succinate dehydrogenase inhibitor (SDHI) fungicides. Sensitivity of representative A. brassicicola isolates (n = 58) from naturally infested broccoli seedlots to QoI and SDHI fungicides was evaluated under in vitro conditions. Interestingly, 15% (n = 9/58) of the A. brassicicola isolates with reduced sensitivity to azoxystrobin also displayed reduced sensitivity to two commonly used SDHI fungicides (boscalid and penthiopyrad) in broccoli, indicating a potential case of cross-resistance to SDHI fungicides. Ninety-three percent of the isolates (n = 54/58) were resistant to both boscalid and penthiopyrad, while 100% isolates displayed sensitivity to fluopyram. Sequence analysis of sdh genes revealed the presence of only one point mutation (H134R) in the sdhC gene in isolates that displayed resistance to boscalid and penthiopyrad. We also developed and validated allele-specific primers targeting the H134R mutation for rapid screening of SDHI resistance in A. brassicicola. We also found that boscalid-resistant isolates exhibited significantly reduced mycelial growth. However, spore germination rates among different resistant isolates were not different, suggesting that resistant isolates remain competitive in natural populations. Overall, this study provides the first evidence of fungicide resistance to SDHI fungicides in A. brassicicola isolated from naturally infested broccoli seeds and underscores the importance of seeds as a potential source for introducing fungicide resistance across geographical locations.

    IMPORTANCE: Alternaria brassicicola is a fungal seed-borne pathogen that can be disseminated via commercial seeds across transplant houses and commercial broccoli fields. Our study provides the first evidence that commercial broccoli seeds can harbor pathogenic A. brassicicola isolates with cross-resistance to two succinate dehydrogenase inhibitor (SDHI) fungicides. We observed that 93% of the A. brassicicola isolates from naturally infested commercial broccoli seeds contained a point mutation that conferred resistance to two SDHI fungicides (boscalid and penthiopyrad). Furthermore, we developed a PCR-based allele-specific assay for the rapid detection and monitoring of fungicide resistance. Our study highlights the importance of seed health testing and potential dissemination of fungicide-resistant isolates locally and globally, thus impacting disease management strategies.

    PMID:40905662 | DOI:10.1128/aem.01083-25

  • Deciphering the Biochemical Functions and Nucleotide Sugar Donor Specificity Determinants of Dicot GT61 Glycosyltransferases Involved in Xylan Substitutions 

    Ruiqin Zhong

    Plant Cell Physiol. 2025 Sep 26:pcaf122. doi: 10.1093/pcp/pcaf122. Online ahead of print.

    ABSTRACT

    Plant cell wall polysaccharide glycosyltransferases catalyze the transfer of sugars from specific nucleotide sugar donors onto specific acceptor substrates. The mechanisms of how their enzymatic specificity is determined is one of the long-standing questions in plant cell wall biology. In this report, we studied the biochemical functions of Arabidopsis and poplar GT61 glycosyltransferases involved in xylan substitutions and investigated the molecular determinants of their nucleotide sugar donor specificity. Enzymatic activity assays of recombinant proteins of Arabidopsis and poplar GT61 members demonstrated that two of them, AtX2AT1 and PtrX2AT1, exhibited xylan 2-O-arabinosyltransferase activities specifically using UDP-Araf, two other ones, AtXYXT2/3, possessed xylan 2-O-xylosyltransferase activities specifically using UDP-Xyl, and three other ones, PtrXXAT1/2/3, were able to catalyze the transfer of 2-O-Araf and 2-O-Xyl onto xylan using both UDP-Araf and UDP-Xyl. Structural modeling and molecular docking of PtrXXAT1 identified amino acid residues involved in interacting with UDP-Araf and UDP-Xyl at the putative active site and site-directed mutagenesis revealed their critical roles in PtrXXAT1 catalytic activities. Furthermore, structural alignment and reciprocal swapping of UDP-Xyl-interacting residues of PtrXXAT1 with their corresponding residues of AtX2AT1 pinpointed key residues determining their nucleotide sugar donor specificity. Our results indicate that Arabidopsis and poplar GT61 members catalyze 2-O-Araf- and/or 2-O-Xyl substitutions of xylan and that subtle structural differences in their substrate-binding pockets could alter their substrate specificity toward nucleotide sugar donors.

    PMID:41001967 | DOI:10.1093/pcp/pcaf122

  • Design of genus-specific semi-nested primers for simple and accurate identification of Enterobacter strains 

    Sara Jordan

    BMC Microbiol. 2025 Jul 28;25(1):456. doi: 10.1186/s12866-025-04175-1.

    ABSTRACT

    BACKGROUND: The genus Enterobacter, in the family Enterobacteriaceae, is of both clinical and environmental importance. This genus has undergone frequent taxonomic changes, making it challenging to identify taxa even at genus level. This study aimed to design Enterobacter genus-specific primers that can be used for simple PCR identification of large sets of putative Enterobacter isolates.

    RESULTS: Comparative genomic approaches were employed to identify genes that were universally present on Enterobacter genomes but absent from the genomes of other members of the family Enterobacteriaceae, based on an initial set of 89 genomes. The presence of these genes was further confirmed in 4,276 Enterobacter RefSeq genomes. While no strictly genus-specific genes were identified, the hpaB gene demonstrated a restricted distribution outside of the genus Enterobacter. Semi-nested primers were designed for hpaB and its flanking gene hpaC (hpaBC) and evaluated on 123 strains in single-tube PCR reactions. All taxa showing positive reactions belonged to the genus Enterobacter. For Enterobacter strains the PCR yielded two amplicons at 110 bp and at 370 bp, while strains only displaying the 110 bp amplicon were classified as Leclercia pneumoniae. A blind-test on 120 strains accessioned as Enterobacter sp. from the USDA-ARS culture collection (NRRL), revealed that one third of the strains had an incorrect genus assignment. Comparison of gene trees of the hpaBC fragment sequences with marker genes frequently used for single-gene barcoding or multi-locus sequence analysis (MLSA) further demonstrated its potential for preliminary species identification.

    CONCLUSIONS: The nested PCR assay represents a rapid and cost-effective approach for preliminary identification of Enterobacter species. As the primer design was based on large-scale genomic comparison, including currently undescribed species clades, it will remain valid even after taxonomic changes within the genus.

    PMID:40722002 | DOI:10.1186/s12866-025-04175-1

  • Detection of the gummy stem blight pathogens (Stagonosporopsis spp.) in watermelon using field-adapted LAMP assays and rapid DNA extraction protocols 

    Jorge Alberto Reyes Pineda

    Plant Dis. 2025 Aug 6. doi: 10.1094/PDIS-12-24-2589-SR. Online ahead of print.

    ABSTRACT

    Gummy stem blight (GSB), caused by three Stagonosporopsis species, S. citrulli, S. cucurbitacearum and S. caricae, is one of the most economically important diseases hindering watermelon production worldwide. Since there is no commercial resistance to GSB in watermelon cultivars, its management depends on cultural practices and preventative fungicides. Therefore, efficient methods for the detection of Stagonosporopsis species that could aid management decisions are required. To help achieve this, a loop-mediated isothermal amplification (LAMP) assay specific to S. citrulli (SCIT850) was developed under two detection formats: fluorescence quantification and endpoint colorimetric detection. The SCIT850 assay was determined to be specific to its target species and exhibited a consistent sensitivity of 1 pg of genomic DNA under both formats. The assay can be combined with a previously reported LAMP assay for the collective detection of the three Stagonosporopsis spp. (STAGY), which have comparable sensitivity to SCIT850 and can aid in species discrimination. A field diagnostic system for GSB-causing Stagonosporopsis was developed by coupling the SCIT850 and STAGY assays to quick DNA extraction protocols. Two DNA extraction methods were tested: one from leaves using cellulose dipsticks, and one from steel rods (typical of spore traps) using Chelex100. With the dipstick method, we detected pathogen DNA in inoculated asymptomatic, mildly infected, and severely infected plants, while with the Chelex100 we detected pathogen DNA from rods infested with as few as 500 spores. The SCIT850 and STAGY assays coupled with these quick sample processing methods could be adapted for field deployment, which would allow growers to make efficient and timely management decisions based on detection of the actual Stagonosporopsis species present in the field.

    PMID:40767855 | DOI:10.1094/PDIS-12-24-2589-SR

  • Determining the causal agents of Alternaria leaf blight and head rot affecting broccoli in the Eastern United States 

    Roy L Davis

    Plant Dis. 2025 May 22. doi: 10.1094/PDIS-01-25-0117-SR. Online ahead of print.

    ABSTRACT

    Alternaria brassicicola is the causal agent typically associated with Alternaria leaf blight and head rot (ABHR) disease in broccoli and related crops in the Eastern United States. Recently a new species, A. japonica, has been reported as causing disease in broccoli and other vegetables in this region. We conducted a multi-state pathogen survey during the growing seasons of 2022 and 2023 to assess the distribution and occurrence of A. japonica in relation to A. brassicicola in five broccoli-producing states. Our approach specifically targeted collection of broccoli leaves with lesions typical of ABHR within commercially grown fields managed using either organic or conventional approaches in Connecticut, Massachusetts, New York, Virginia, and Georgia. Only typical ABHR leaf lesions were selected for pathogen isolation and, subsequently, sequencing of the Alternaria major allergen a1 gene was used to identify Alternaria species. The predominant species isolated was A. brassicicola (88% in 2022 and 94% in 2023) and the second most common was A. alternata (12% in 2022 and 6% in 2023), which was obtained from fields in Connecticut and Massachusetts in 2022, and in Virginia in both years. Alternaria japonica was not found in either year. Symptoms of A. alternata were indistinguishable from A. brassicicola, as were colony morphologies. While A. alternata is considered a generalist and of little consequence for broccoli, it is considered a pathogen of significance on multiple crops (blueberry, citrus, pistachios), but there remains scant information on the disease etiology on broccoli. Therefore, we inoculated broccoli with A. alternata in controlled conditions in order to shed light on possible differences in infectivity of these species on broccoli. Results of our study showed that A. alternata is pathogenic on broccoli, capable of initiating infection and causing lesions typical of ABHR. This indicates that future disease surveys of ABHR should conclusively identify species of Alternaria that are causing disease. Additional research is needed to determine the significance of this finding in relation to yield impacts, epidemiology, fungicide resistance, and management recommendations.

    PMID:40403277 | DOI:10.1094/PDIS-01-25-0117-SR

  • Discovering leaf and stripe rust resistance in soft red winter wheat through genome-wide association studies 

    John W Bagwell

    Plant Genome. 2025 Jun;18(2):e70055. doi: 10.1002/tpg2.70055.

    ABSTRACT

    Leaf rust (LR) and stripe rust (YR), which are caused by Puccinia triticina and Puccinia striiformis, respectively, are among the most devastating wheat rusts worldwide. These diseases can be managed by using genetically resistant cultivars, an economical and environmentally safer alternative to fungicides. Over 100 and 80 Lr and Yr resistance genes have been discovered, respectively; however, rust pathogens are overcoming introduced resistance genes in the southeastern United States. Genome-wide association study has emerged as a valuable tool to identify new LR and YR resistance loci. In this study, a panel of 263 soft red winter wheat genotypes was evaluated for LR and YR severity in Plains, GA, and Williamson, GA, in a randomized complete block design of two replicates during 2019 and 2021-2023. Also, LR and YR infection types were assessed on seedlings at the three leaf stage in three greenhouse trials. A total of 26 significant quantitative trait loci (QTL) explaining 0.6%-30.8% phenotypic variance (PV) was detected by at least two of the five GAPIT models (BLINK, CMLM, FarmCPU, GLM, and MLM) tested. Nine major QTL included QLrYr-2A.1 linked to single-nucleotide polymorphism S2A_20855466, which had the highest overall PV (30.8%) for response to both rust pathogens in the field. Using the Chinese Spring Reference Genome Version 1.0, we detected 16 candidate genes, and four known R genes and QTL overlapped two major QTL. Of these QTL, 16 are likely novel genetic loci with potential for marker-assisted selection.

    PMID:40495572 | DOI:10.1002/tpg2.70055

  • Discovery of iridoid cyclase completes the iridoid pathway in asterids 

    Maite Colinas

    Nat Plants. 2025 Oct 3. doi: 10.1038/s41477-025-02122-6. Online ahead of print.

    ABSTRACT

    Iridoids are specialized monoterpenes ancestral to asterid flowering plants1,2 that play key roles in defence and are also essential precursors for pharmacologically important alkaloids3,4. The biosynthesis of all iridoids involves the cyclization of the reactive biosynthetic intermediate 8-oxocitronellyl enol. Here, using a variety of approaches including single-nuclei sequencing, we report the discovery of iridoid cyclases from a phylogenetically broad sample of asterid species that synthesize iridoids. We show that these enzymes catalyse formation of 7S-cis-trans and 7R-cis-cis nepetalactol, the two major iridoid stereoisomers found in plants. Our work uncovers a key missing step in the otherwise well-characterized early iridoid biosynthesis pathway in asterids. This discovery unlocks the possibility to generate previously inaccessible iridoid stereoisomers, which will enable metabolic engineering for the sustainable production of valuable iridoid and iridoid-derived compounds.

    PMID:41044409 | DOI:10.1038/s41477-025-02122-6

  • Dr. Diane Okamuro Gather & Grow Webinar

    Gather & Grow Webinar: What is it Like to be a Program Manager at NSF?

    Dr. Diane Okamuro, National Science Foundation Program Manager

    April 17, 2025 | Noon – 1PM

    Join Zoom

     

    Dr. Diane Jofuku Okamuro is a Program Director for the Plant Genome Research Program (PGRP) at the National Science Foundation, Directorate for Biological Sciences (BIO), Division of Integrative Organismal Systems. The PGRP is broad in scope and supports functional genomics tool development and basic discovery research on a genome-wide scale that will provide new insights into plant processes that are important to the U.S. economy. The PGRP Cluster also manages the Plant Genome Research Postdoctoral Fellowships program which is part of the BIO-wide Postdoctoral Research Fellowships in Biology program. In addition, she currently serves on the Working Group for the Biology Integration Institutes (BII) program which supports interdisciplinary, collaborative teams that perform research, education and training on critical questions that span multiple disciplines within and beyond biology.
    Dr. Okamuro received her Ph.D. in Biology from UCLA and is a plant molecular geneticist by training. She has broad-based experience in cutting-edge functional genomics technologies and has held research and management positions in both academia and industry prior to joining NSF in 2005.

  • Dr. Donglin Zhang recently named a 2024 Plant Biotechnology Fellow by the American Society for Horticultural Sciences!

    Congratulations to Dr. Donglin Zhang for recently being named a 2024 Plant Biotechnology Fellow by the American Society for Horticultural Sciences!

    Fellows of the Society are recognized for outstanding contributions to horticulture in one or more of the following areas: research, teaching, administration, or extension on a state, national, and/or international level; exhibition of leadership in horticultural business or industry pertinent to and compatible with the objectives of the Society; and noteworthy contributions to ASHS objectives (“to promote and encourage national and international interest in scientific research and education in horticulture in all its branches”). This may be demonstrated by the nominee’s direct and effective participation in the affairs and activities of the Society (including its Regional Groups) and/or by active involvement in the affairs of other allied organizations having objectives essentially the same as those of ASHS (including international organizations and those in countries other than the United States).

    Election as a Fellow of the Society is the highest honor that ASHS can bestow on its members, in recognition of truly outstanding contributions to horticulture and the Society.

    Congratulations, Dr. Zhang!

  • Dr. Rishi Masalia Gather & Grow Webinar

  • Draft genome assemblies of 38 Aspergillus parasiticus isolates collected from South Georgia crop fields 

    Sunil S Gangurde

    Microbiol Resour Announc. 2025 Sep 12:e0008325. doi: 10.1128/mra.00083-25. Online ahead of print.

    ABSTRACT

    Aspergillus parasiticus is a fungus recognized for producing highly carcinogenic mycotoxins. In this study, we collected 38 isolates of A. parasiticus from fields in South Georgia. We performed whole genome re-sequencing and developed 38 draft genome assemblies of A. parasiticus. The average genome size was 38.7 Mb, with larger genomes (~40 Mb) found in peanut fields in Turner County. Scaffold N50 was recorded highest for isolates collected from the corn fields of Tifton. The average BUSCO completeness score for these assemblies was 99.1%. The genome sequences generated for these 38 isolates will serve as a valuable genomic resource for the community working on aflatoxin mitigation strategies in crops.

    PMID:40938094 | DOI:10.1128/mra.00083-25

  • Drought adaptation index (DAI) based on BLUP as a selection approach for drought-resilient switchgrass germplasm 

    Shiva Om Makaju

    Front Genet. 2025 Aug 25;16:1626083. doi: 10.3389/fgene.2025.1626083. eCollection 2025.

    ABSTRACT

    This study introduces a Drought Adaptation Index (DAI), derived from Best Linear Unbiased Prediction (BLUP), as a method to assess drought resilience in switchgrass (Panicum virgatum L.). A panel of 404 genotypes was evaluated under drought-stressed (CV) and well-watered (UC) conditions over four consecutive years (2019-2022). BLUP-estimated biomass yields were used to calculate the DAI, which enabled classification of genotypes into four adaptation groups: very well-adapted, well-adapted, adapted, and unadapted. The DAI was compared with conventional drought tolerance indices, including the Stress Susceptibility Index (SSI), Stress Tolerance Index (STI), Geometric Mean Productivity (GMP), and Yield Stability Index (YSI). Correlation analyses demonstrated strong agreement between DAI and these indices, supporting its validity and consistency. Biplot analyses using the Genotype plus Genotype-by-Environment Interaction (GGE) and Additive Main Effects and Multiplicative Interaction (AMMI) models revealed significant genotype-by-environment interactions (GEI) and identified J222.A, J463.A, and J295.A. A as high-performing genotypes, with J222.A exhibiting greater yield stability across treatments and years. Additionally, DAI isoline curves provided a graphical representation of differential genotype performance under drought and control conditions. These visualizations aided in distinguishing genotypes with stable and superior biomass yield across contrasting environments. Overall, the BLUP-based DAI is a robust and practical selection tool that improves the accuracy of identifying drought-resilient, high-yielding switchgrass genotypes. Its integration into breeding programs offers a comprehensive framework for improving biomass productivity and stress adaptation under variable climatic conditions. The application of DAI supports the development of climate-resilient cultivars and contributes to sustainable bioenergy and forage production systems.

    PMID:40927363 | PMC:PMC12414770 | DOI:10.3389/fgene.2025.1626083

  • Engineering chromosome number in plants 

    Feng Zhang

    Science. 2025 Nov 20;390(6775):786-787. doi: 10.1126/science.aec7902. Epub 2025 Nov 20.

    ABSTRACT

    Chromosome engineering produces a reduced eight-chromosome karyotype in Arabidopsis thaliana.

    PMID:41264719 | DOI:10.1126/science.aec7902

  • Enzymatic epimerization of monoterpene indole alkaloids in kratom 

    Allwin McDonald

    Nat Chem Biol. 2025 Jul 16. doi: 10.1038/s41589-025-01970-9. Online ahead of print.

    ABSTRACT

    Monoterpene indole alkaloids (MIAs) are a large, structurally diverse class of bioactive natural products. These compounds are biosynthetically derived from a stereoselective Pictet-Spengler condensation that generates a tetrahydro-β-carboline scaffold characterized by a 3S stereocenter. However, a subset of MIAs contains a noncanonical 3R stereocenter. Here we report the basis for 3R-MIA biosynthesis in Mitragyna speciosa (kratom). We discover the presence of the iminium species (20S)-3-dehydrocorynantheidine, which supports isomerization of 3S to 3R via oxidation and stereoselective reduction downstream of the initial Pictet-Spengler condensation. Isotopologue feeding experiments identify the sites for downstream MIA pathway biosynthesis as well as the oxidase/reductase pair that catalyzes this epimerization. This oxidase/reductase pair has broad substrate specificity, suggesting that this pathway may be responsible for the formation of many 3R-MIAs and downstream spirooxindole alkaloids in kratom. The elucidation of this epimerization mechanism allows biocatalytic access to a range of pharmacologically active spirooxindole alkaloid compounds.

    PMID:40670688 | DOI:10.1038/s41589-025-01970-9

  • Estimating Hospitalization Expenditures Associated with Chronic Diseases and Multimorbidity for Older Adults – Guangzhou City, Guangdong Province, China, 2017-2019 

    Fei Zhao

    China CDC Wkly. 2025 Aug 1;7(31):1031-1037. doi: 10.46234/ccdcw2025.175.

    ABSTRACT

    WHAT IS ALREADY KNOWN ABOUT THIS TOPIC?: Chronic diseases and multimorbidity impose substantial burdens on healthcare systems globally, particularly in aging populations, resulting in elevated healthcare utilization rates and increased expenditures.

    WHAT IS ADDED BY THIS REPORT?: This study validates previous research findings using an extensive administrative database from a major city in South China. Additionally, it provides comprehensive estimates of annual hospitalization expenditures per patient associated with chronic diseases and multimorbidity patterns among older adults, elucidating the economic burden and cost variations across specific diseases and multimorbidity combinations. Cancer, cerebrovascular disease (CVD), and heart disease – whether occurring individually or in conjunction with other chronic conditions, particularly within complex multimorbidity patterns – were associated with substantial annual hospitalization expenditures and significant healthcare resource utilization.

    WHAT ARE THE IMPLICATIONS FOR PUBLIC HEALTH PRACTICE?: Disease burden studies provide critical evidence for prioritizing public health policies and targeted interventions. Policymakers should implement comprehensive prevention strategies, evidence-based interventions, appropriate reimbursement policies, and integrated management approaches to control disease progression and reduce healthcare expenditures.

    PMID:40831617 | PMC:PMC12360313 | DOI:10.46234/ccdcw2025.175

  • Ethylene-releasing plant growth regulators promote ripening initiation by stimulating sugar, acid and anthocyanin metabolism in blueberry (Vaccinium ashei) 

    Tej P Acharya

    BMC Plant Biol. 2025 Jun 5;25(1):766. doi: 10.1186/s12870-025-06799-x.

    ABSTRACT

    BACKGROUND: Fruit ripening is a coordinated process that leads to an increase in sugars, decrease in acids and accumulation of pigments. Blueberry fruit exhibit an atypical climacteric ripening behavior. These fruit display an increase in respiration and ethylene production during ripening, however ethylene synthesis is developmentally regulated. In this study, the effect of ethylene on blueberry fruit ripening was investigated via preharvest applications of ethylene-releasing plant growth regulators (PGRs), ethephon and 1-aminocyclopropane 1-carboxylic acid (ACC), in one southern highbush cultivar, Miss Lilly in 2019, and two rabbiteye cultivars, Premier and Powderblue in 2019 and 2020. Further, the effects of these two PGRs on fruit metabolism during ripening in the two rabbiteye cultivars, and postharvest fruit quality in all three cultivars were evaluated.

    RESULTS: Both PGRs increased ethylene evolution within 1-3 days after treatment (DAT). Ethephon and ACC applications increased the rate of ripening within 5 DAT in all cultivars, and increased ripe (blue) fruit by up to 35% and 29%, respectively between 7 to 10 DAT compared to the control. Metabolite analysis revealed that PGR treatments resulted in an immediate, but transient increase in sucrose, glucose and fructose, in ‘Premier’ at 3 DAT. Malate decreased at 3 DAT in response to both PGR treatments in ‘Premier’, and at 5 DAT in ethephon treatment in both cultivars. A rapid increase in the concentration of multiple anthocyanins was noted at 3 DAT in response to both PGRs in ‘Premier’ and ‘Powderblue’. Gene expression analysis revealed an increase in transcript abundance of VACUOLAR INVERTASE (vINV) and multiple anthocyanin biosynthesis genes between 1 and 3 DAT after PGR treatments in both cultivars, supporting the metabolite changes. However, the alteration in fruit metabolite concentrations were not sustained, and similar in PGR-treated fruit compared to the control in ripe fruit harvested at 10 DAT. Postharvest fruit quality attributes, such as firmness, total soluble solids, titratable acidity, and visual quality, were not consistently affected by the PGR applications compared to control treatments across all cultivars. A decrease in fruit weight was noted, although not consistently, in response to PGR treatments.

    CONCLUSIONS: Overall, this study demonstrates that ethylene plays a crucial role in promoting ripening via rapid and transient stimulation of sugar, acid and anthocyanin metabolism. The promotion of fruit ripening by ethylene-releasing PGRs can lead to minimal but inconsistent changes in fruit quality attributes during postharvest storage.

    PMID:40474063 | DOI:10.1186/s12870-025-06799-x

  • Evaporative cooling signals for wound healing in plants 

    Joseph Balem

    bioRxiv [Preprint]. 2025 May 28:2025.05.23.655667. doi: 10.1101/2025.05.23.655667.

    ABSTRACT

    Repairing a damaged body part is critical for the survival of any organism. In plants, tissue damage induces rapid responses that activate defense, regeneration and wound healing. While early wound signaling mediated by phytohormones, electrical signals and reactive oxygen species is well-characterized, the mechanisms governing the final stages of wound healing remain poorly understood. Here, we show that wounding in Arabidopsis leaves induces localized cooling, likely due to evaporative water loss, accompanied by the activation of cold-responsive genes. The subsequent disappearance of localized cooling and deactivation of cold-responsive genes serve as a quantitative marker of wound healing. Based on these observations, we developed a workflow by leveraging computer vision and deep learning to monitor the dynamics of wound healing. We found that CBFs transcription factors relay injury-induced cooling signal to wound healing. Thus, our work advances our understanding of tissue repair and provides a tool to quantify wound healing in plants.

    PMID:40502075 | PMC:PMC12154623 | DOI:10.1101/2025.05.23.655667

  • Everyday norms have become more permissive over time and vary across cultures 

    Kimmo Eriksson

    Commun Psychol. 2025 Oct 7;3(1):145. doi: 10.1038/s44271-025-00324-4.

    ABSTRACT

    Every social situation that people encounter in their daily lives comes with a set of unwritten rules about what behavior is considered appropriate or inappropriate. These everyday norms can vary across societies: some societies may have more permissive norms in general or for certain behaviors, or for certain behaviors in specific situations. In a preregistered survey of 25,422 participants across 90 societies, we map societal differences in 150 everyday norms and show that they can be explained by how societies prioritize individualizing moral foundations such as care and liberty versus binding moral foundations such as purity. Specifically, societies with more individualistic morality tend to have more permissive norms in general (greater liberty) and especially for behaviors deemed vulgar (less purity), but they exhibit less permissive norms for behaviors perceived to have negative consequences in specific situations (greater care). By comparing our data with available data collected twenty years ago, we find a global pattern of change toward more permissive norms overall but less permissive norms for the most vulgar and inconsiderate behaviors. This study explains how social norms vary across behaviors, situations, societies, and time.

    PMID:41057696 | DOI:10.1038/s44271-025-00324-4

  • Factors underlying a latitudinal gradient in the S/G lignin monomer ratio in natural poplar variants 

    Weiwei Zhu

    Proc Natl Acad Sci U S A. 2025 Aug 26;122(34):e2503491122. doi: 10.1073/pnas.2503491122. Epub 2025 Aug 20.

    ABSTRACT

    The chemical composition of wood plays a pivotal role in the adaptability and structural integrity of trees. However, few studies have investigated the environmental factors that determine lignin composition and its biological significance in plants. Here, we examined the lignin syringyl-to-guaiacyl (S/G) ratio in members of a Populus trichocarpa population sourced from their native habitat and conducted a genome wide association study to identify genes linked to lignin formation. Our results revealed many significant associations, suggesting that lignin biosynthesis is a complex polygenic trait. Additionally, we found an increase in the S/G ratio from northern to southern geographic origin of the trees sampled, along with a corresponding metabolic and transcriptional reprogramming of xylem cell wall biosynthesis. Further molecular analysis identified a mutation in a cell wall laccase genetically associated with higher S/G ratios that predominate in trees from warmer lower latitudes. Collectively, our findings suggest that lignin heterogeneity arises from an evolutionary process enabling poplar adaptation to different climatic challenges.

    PMID:40833412 | DOI:10.1073/pnas.2503491122

  • FFAR Announces 26 Awardees of FFAR Fellows Program naming Shreena Pradhan

    WASHINGTON (August 11, 2021) – Climate change, a growing population and evolving pests and pathogens threaten the security of our global food supply. Employers need trained scientists to conduct research that helps farms and food systems adapt to these challenges. The Foundation for Food & Agriculture Research (FFAR) and North Carolina State University are excited to announce the 26 students selected for the 2021 FFAR Fellows Program. This unique three-year program provides professional development training and mentorship to doctoral students conducting research in alignment with FFAR’s six Challenge Areas.

  • FX-Cell: a method for single-cell RNA sequencing on difficult-to-digest and cryopreserved plant samples 

    Xin Ming

    Nat Methods. 2025 Nov 27. doi: 10.1038/s41592-025-02900-2. Online ahead of print.

    ABSTRACT

    Single-cell RNA sequencing in plants requires the isolation of high-quality protoplasts-cells devoid of cell walls. However, many plant tissues and organs are resistant to enzymatic digestion, posing a significant barrier to advancing single-cell multi-omics in plant research. Furthermore, for field-grown crops, the lack of immediate laboratory facilities presents another major challenge for timely protoplast preparation. Here, to address these limitations, we developed FX-Cell and its derivatives, FXcryo-Cell and cryoFX-Cell, to enable single-cell RNA sequencing with both difficult-to-digest and cryopreserved plant samples. By optimizing the fixation buffer and minimizing RNA degradation, our approach ensures efficient cell wall digestion at high temperatures while maintaining high-quality single cells, even after long-term storage at -80 °C, and circumvents use of nuclei, which are not representative of the pool of translatable messenger RNAs. We successfully constructed high-quality cell atlases for rice tiller nodes, rhizomes of wild rice and maize crown roots grown under field conditions. Moreover, these methods enable the accurate reconstruction of plant acute wounding responses at single-cell resolution. Collectively, these advancements expand the applicability of plant single-cell genomics across a wider range of species and tissues, paving the way for comprehensive Plant Cell Atlases for plant species.

    PMID:41310055 | DOI:10.1038/s41592-025-02900-2

  • Gene Expression Differentiation Is Consistent with Local Adaptation across an Elevational Gradient in Drummond’s Rockcress (Boechera stricta) 

    Shelby L Tisinai

    J Hered. 2025 Oct 15:esaf081. doi: 10.1093/jhered/esaf081. Online ahead of print.

    ABSTRACT

    A central goal of evolutionary biology is to understand the mechanisms conferring adaptation. Gene expression is sensitive to environmental variability; thus, investigating gene expression differentiation among populations may reveal signatures of selection from predictable environmental conditions. Environmental pressures that covary with elevation gain (e.g., temperature) result in stark environmental differences along short distances. The phenological and life history traits of plants inhabiting elevational gradients might track these variables, providing an opportunity for testing hypotheses. Boechera stricta occupies a steep elevation gradient in the Rocky Mountains. Here, we grew F3 seeds from at least two genotypes each from five populations of B. stricta in a greenhouse. Analysis of leaf RNAseq data permitted tests of these hypotheses: 1) populations exhibit significant among population genetic variation in gene expression; 2) differentiation in gene expression (QST) exceeds neutral expectations (FST); and 3) the putative functions of differentially expressed genes are predicable based on a priori knowledge of environmental pressures that vary with elevation. Differentiation in gene expression (average QST = 0.53) significantly exceeded neutral differentiation (average FST = 0.17), implicating selection as a potential cause of genetically divergent patterns of gene expression. The putative functions of differentially expressed genes covarying with elevation were enriched for biological processes related to conditions that vary with elevation (circadian rhythm, response to light, chloroplast organization, and vegetative to reproductive meristem transitions). This study reveals considerable differentiation in gene expression, which may provide a mechanism for rapid adaptation to local environmental conditions in this and other species.

    PMID:41092278 | DOI:10.1093/jhered/esaf081

  • Genetic and environmental influences on the distributions of three chromosomal drive haplotypes in maize 

    Meghan J Brady

    bioRxiv [Preprint]. 2025 May 27:2025.05.22.655462. doi: 10.1101/2025.05.22.655462.

    ABSTRACT

    Meiotic drive elements are regions of the genome that are transmitted to progeny at frequencies that exceed Mendelian expectations, often to the detriment of the organism. In maize there are three prevalent chromosomal drive elements known as Abnormal chromosome 10 (Ab10), K10L2, and the B chromosome. There has been much speculation about how these drivers might interact with each other and the environment in traditional maize landraces and their teosinte ancestors. Here we used genotype-by-sequencing data to score more than 10,000 maize and teosinte lines for the presence or absence of each driver. Less than ~0.5% of modern inbred lines carry chromosomal drivers. Among individuals from 5331 open-pollinated landraces, 6.32% carried Ab10, 5.16% carried K10L2, and 12.28% carried at least one B chromosome. Using a GWAS approach we identified unlinked loci that associate with the presence or absence of the selfish genetic elements. Many genetic modifiers are positively associated with the drivers, suggesting that there may have been selection for alleles that ameliorate their negative fitness consequences. We then assessed the contributions of population structure, associated loci, and the environment on the distribution of each chromosomal driver. There was no significant relationship between any chromosomal driver and altitude, contrary to conclusions based on smaller studies. Our data suggest that the distribution of the major chromosomal drivers is primarily influenced by neutral processes and the deleterious fitness consequences of the drivers themselves. While each driver has a unique relationship to genetic background and the environment, they are largely unconstrained by either.

    PMID:40501570 | PMC:PMC12154789 | DOI:10.1101/2025.05.22.655462

2019 Cohort

  • 1H-NMR Guided Isolation of Bioactive Compounds from Species of the Genus Piper 

    Author: Ian S Wallace 

    Molecules. 2025 Apr 30;30(9):2020. doi: 10.3390/molecules30092020.

    ABSTRACT

    The discovery of bioactive natural products is often challenged by the complexity of isolating and characterizing active compounds within diverse mixtures. Previously, we introduced a 1H NMR-based weighted gene correlation network analysis (WGCNA) approach to identify spectral features linked to growth inhibitory activity of Piper (Piperaceae) leaf extracts against model plant, fungal, and bacterial organisms. This method enabled us to prioritize specific spectral features linked to bioactivity, offering a targeted approach to natural product discovery. In this study, we validate the predictive capacity of the WGCNA by isolating the compounds responsible for the bioactivity-associated resonances and confirming their antifungal efficacy. Using growth inhibition assays, we verified that the isolated compounds, including three novel antifungal agents, exhibited significant bioactivity. Notably, one of these compounds contains a rare imidazolium heterocyclic motif, marking a new structural class in Piper. These findings substantiate the 1H NMR-based WGCNA as a reliable tool for identifying structural types associated with biological activity, streamlining the process of discovering bioactive natural products in complex extracts.

    PMID:40363825 | PMC:PMC12073215 | DOI:10.3390/molecules30092020

  • 2023 Retreat Agenda

  • 2025 Spring Symposium Save the Date

  • 35th E. S. Luttrell Lecture

  • A Case Study for Visual Detection of a Systemic Disease: Optimizing Identification of Phony Peach Disease Based on Statistical and Machine Learning Models 

    Weiqi Luo

    Phytopathology. 2025 Jun 22. doi: 10.1094/PHYTO-03-25-0093-R. Online ahead of print.

    ABSTRACT

    Phony peach disease (PPD), caused by Xylella fastidiosa subsp. multiplex (Xfm), poses a significant threat to commercial peach orchards in Georgia. Early and accurate detection is essential for effective disease management, yet visual assessment remains the primary approach for diagnosing PPD symptoms due to the high cost and logistical challenges of qPCR-based detection of Xfm. We evaluated the accuracy of visual PPD assessment and examined the factors influencing rater performance, symptom reliability, and optimal survey deployment strategies with CART/Random Forest analyses and simulations. Internode length was the most reliable symptom for PPD identification in two peach cultivars, consistently outperforming other physical traits such as canopy flatness and shape. Primer pair C06Xf-bamA had the greatest relative sensitivity, making it the preferred choice for qPCR confirmation. Principal component analysis suggested that rater experience significantly improved agreement with qPCR results and repeated assessments of the same orchards further enhanced consistency for raters. Simulations results suggested that deploying two experienced raters may provide the highest detection diagnostic accuracy for survey purposes, particularly when qPCR-based pathogen detection is unavailable. Last, PPD-affected trees, through PCR verification and visual identification, exhibited higher mortality rates than Xfm-negative trees, reinforcing the need for early detection and removal to limit disease spread. These findings underscore the importance of strategic rater deployment, targeted symptom selection, and integrating molecular diagnostics when feasible.

    PMID:40544457 | DOI:10.1094/PHYTO-03-25-0093-R

  • A cell-type-specific regulon controlling monoterpene indole alkaloid biosynthesis with feedback and feedforward activation loops 

    Chenxin Li

    New Phytol. 2025 Nov 9. doi: 10.1111/nph.70712. Online ahead of print.

    ABSTRACT

    Monoterpene indole alkaloids (MIA) are a diverse class of plant natural products produced by a subset of lineages within the Asterid clade of eudicots. The diversity of MIAs provides a unique opportunity to study not only the evolution of biosynthetic genes but also their regulation. In this study, we investigate the cell type specificity of biosynthetic genes and coexpressed transcription factors (TFs) in two MIA-producing Asterid species, Catharanthus roseus, a well-studied MIA-producing species, and Camptotheca acuminata, which belongs to an early-diverging lineage of the Asterid clade. We generated single-cell RNA-seq data from the C. acuminata stem, the primary site of camptothecin biosynthesis. We found that MIA biosynthetic genes in C. acuminata are specific to exceptionally rare cell populations. We discovered MYB and bHLH TFs coexpressed in the same cell types as MIA biosynthetic genes in the C. acuminata stem. Interestingly, the C. roseus orthologs of these TFs are idioblast-specific and activate MIA biosynthetic genes in C. roseus upon overexpression. We constructed an extended gene regulatory network for the idioblast metabolic regulon in C. roseus, which contains both feedback and feedforward activation loops. This study demonstrates co-option of the same clades of TFs for regulation of cell-type-specific MIA biosynthesis across two Asterid species separated by c. 115 million years of evolution. Investigating cell-type-specific TFs that are coexpressed with biosynthetic genes across multiple species is a powerful strategy to increase the power for the discovery of plant metabolic regulators.

    PMID:41208325 | DOI:10.1111/nph.70712

  • A compendium of nonredundant short polymerase III promoters for CRISPR applications 

    Michihito Deguchi

    Plant Physiol. 2025 Jul 3;198(3):kiaf294. doi: 10.1093/plphys/kiaf294.

    ABSTRACT

    Minimal native and synthetic Polymerase III promoters enable efficient and customizable CRISPR multiplexing in plants, expanding genome engineering capabilities

    PMID:40673482 | PMC:PMC12268498 | DOI:10.1093/plphys/kiaf294

  • A global dataset of terrestrial biological nitrogen fixation 

    Carla R Reis Ely

    Sci Data. 2025 Aug 5;12(1):1362. doi: 10.1038/s41597-025-05131-4.

    ABSTRACT

    Biological nitrogen fixation (BNF) is the main natural source of new nitrogen inputs in terrestrial ecosystems, supporting terrestrial productivity, carbon uptake, and other Earth system processes. We assembled a comprehensive global dataset of field measurements of BNF in all major N-fixing niches across natural terrestrial biomes derived from the analysis of 376 BNF studies. The dataset comprises 32 variables, including site location, biome type, N-fixing niche, sampling year, quantification method, BNF rate (kg N ha-1 y-1), the percentage of nitrogen derived from the atmosphere (%Ndfa), N fixer or N-fixing substrate abundance, BNF rate per unit of N fixer abundance, and species identity. Overall, the dataset combines 1,207 BNF rates for trees, shrubs, herbs, soil, leaf litter, woody litter, dead wood, mosses, lichens, and biocrusts, 152 herb %Ndfa values, 1,005 measurements of N fixer or N-fixing substrate abundance, and 762 BNF rates per unit of N fixer abundance for a total of 424 species across 66 countries. This dataset facilitates synthesis, meta-analysis, upscaling, and model benchmarking of BNF fluxes at multiple spatial scales.

    PMID:40764484 | DOI:10.1038/s41597-025-05131-4

  • A high-quality genome assembly of the tetraploid Teucrium chamaedrys unveils a recent whole genome duplication and a large biosynthetic gene cluster for diterpenoid metabolism 

    Abigail E Bryson

    Plant Commun. 2025 Jun 3:101393. doi: 10.1016/j.xplc.2025.101393. Online ahead of print.

    ABSTRACT

    Teucrium chamaedrys, also called wall germander, is a small woody shrub native to the Mediterranean region. Its name is derived from the Greek words meaning ‘ground oak’, since its tiny leaves resemble those of an oak tree. Teucrium species are proliferative producers of diterpenes, which afford them valuable properties widely co-opted in traditional and western medicines. Sequence and assembly of the 3 Gbp tetraploid T. chamaedrys revealed 74 diterpene synthase genes, with the vast representation of these diterpene synthases clustered along four genomic loci. Comparative genomics revealed that this cluster is mirrored in the closely related species, Teucrium marum. Along with the presence of several cytochrome p450 sequences, this region is the one of largest biosynthetic gene clusters identified. Teucrium is well known for accumulating clerodane-type diterpenoids which are produced from a kolavanyl diphosphate precursor. To elucidate the complex biosynthetic pathways of these medicinal compounds, we identified and functionally characterized several kolavanyl diphosphate synthases from T. chamaedrys. Its remarkable chemistry and tetraploidy make T. chamaedrys an interesting and unique model for studying genomic evolution and adaptation in plants.

    PMID:40468595 | DOI:10.1016/j.xplc.2025.101393

  • A nitric oxide reductase is a key enzyme target for eliminating fungal emissions of nitrous oxide 

    Blake A Oakley

    Fungal Genet Biol. 2025 Sep 23:104038. doi: 10.1016/j.fgb.2025.104038. Online ahead of print.

    ABSTRACT

    Nitrous oxide (N2O) derived from agricultural activity is a major contributor to Earth’s greenhouse effect. Synthetic nitrogen fertilizer applied at high levels, particularly combined with heavy rainfall events, generates hot spots of N2O emissions in agricultural fields due to the process of microbial denitrification. Here, a key conserved fungal denitrification enzyme necessary for N2O emissions was identified. Phylogenetic analysis revealed that fungal NOR1-like genes, with rare exceptions, are highly conserved and confined to the phylum Ascomycota. Plant pathogenic Fusarium species that possess NOR1 exhibited drastic differences in N2O production based on denitrification potential. Functional characterization of the p450nor nitric oxide reductase encoding gene, NOR1, in the soil-borne denitrifying maize pathogen, Fusarium verticillioides, showed that this enzyme is critical for fungal N2O production. Deletion of the single copy NOR1 gene in F. verticillioides eliminated N2O emissions. Complementation of deletion mutants via the NOR1 gene add-back restored wild type N2O emission levels and segregation analysis further corroborated the pivotal role of NOR1 for N2O emissions. We suggest targeting of the NOR1 enzyme as an effective strategy to reduce fungal-based N2O emissions.

    PMID:40998212 | DOI:10.1016/j.fgb.2025.104038

  • Aerial root formation in Oaxacan maize (Zea mays) landraces persists into the adult phase and is minimally affected by soil nitrogen and ambient humidity 

    Rafael E Venado

    Front Plant Sci. 2025 Jul 11;16:1607733. doi: 10.3389/fpls.2025.1607733. eCollection 2025.

    ABSTRACT

    Maize (Zea mays L.) is the most widely produced crop in the world, and conventional production requires significant amounts of synthetic nitrogen fertilizer, which has negative economic and environmental consequences. Maize landraces from Oaxaca, Mexico, can acquire nitrogen from nitrogen-fixing bacteria that live in a mucilage secreted by aerial nodal roots. The development of these nodal roots is a characteristic traditionally associated with the juvenile vegetative stage of maize plants. However, mature Oaxacan landraces develop many more nodes with aerial roots than commercial maize varieties. Our study shows that Oaxacan landraces develop aerial roots during the juvenile and adult vegetative phases and even during early flowering under greenhouse and field conditions. Surprisingly, the development of these roots was only minimally affected by soil nitrogen and ambient humidity. These findings are an essential first step in developing maize varieties to reduce fertilizer needs in maize production across different environmental conditions.

    PMID:40718026 | PMC:PMC12289584 | DOI:10.3389/fpls.2025.1607733

  • An updated sulfate transporter phylogeny uncovers a perennial-specific subgroup associated with lignification 

    Samantha M Surber

    Tree Physiol. 2025 Jul 11:tpaf080. doi: 10.1093/treephys/tpaf080. Online ahead of print.

    ABSTRACT

    Sulfate-proton co-transporters (SULTRs) mediate sulfate uptake, transport, storage, and assimilation in plants. The SULTR family has historically been classified into four groups (SULTR1-SULTR4), with well-characterized roles for SULTR groups 1, 2, and 4. However, the functions of the large and diverse SULTR3 group remain poorly understood. Here, we present an updated phylogenetic analysis of SULTRs across angiosperms, including multiple early-divergent lineages. Our results suggest that the enigmatic SULTR3 group comprises four distinct subfamilies that predate the emergence of angiosperms, providing a basis for reclassifying the SULTR family into seven subfamilies. This expanded classification is supported by subfamily-specific gene structures and amino acid substitutions in the substrate-binding pocket. Structural modeling identified three serine residues uniquely lining the substrate-binding pocket of SULTR3.4, enabling three hydrogen bonds with the phosphate ion. The data support the proposed neofunctionalization of this subfamily for phosphate allocation within vascular tissues. Transcriptome analysis of Populus tremula × alba revealed divergent tissue expression preferences among SULTR subfamilies and between genome duplicates. We observed partitioned expression in vascular tissues among the four SULTR3 subfamilies, with PtaSULTR3.4a and PtaSULTR3.2a preferentially expressed in primary and secondary xylem, respectively. Gene coexpression analysis revealed coordinated expression of PtaSULTR3.4a with genes involved in phosphate starvation responses and nutrient transport, consistent with a potential role in phosphate homeostasis. In contrast, PtaSULTR3.2a was strongly coexpressed with lignification and one-carbon metabolism genes and their upstream transcription regulators. PtaSULTR3.2a belongs to a eudicot-specific branch of the SULTR3.1 subfamily found only in perennial species, suggesting a specialized role in lignifying tissues. Together, our findings provide a refined phylogenetic framework for the SULTR family and suggest that the expanded SULTR3 subfamilies have undergone neofunctionalization during the evolution of vascular and perennial plants.

    PMID:40643194 | DOI:10.1093/treephys/tpaf080

  • Anionic lipids direct efficient microfluidic encapsulation of stable and functionally active proteins in lipid nanoparticles 

    Suresh Ambati

    Commun Mater. 2025;6(1):34. doi: 10.1038/s43246-025-00749-8. Epub 2025 Feb 22.

    ABSTRACT

    Because proteins do not efficiently pass through the plasma membrane, protein therapeutics are limited to target ligands located at the cell surface or in serum. Lipid nanoparticles can facilitate delivery of polar molecules across a membrane. We hypothesized that because most proteins are amphoteric ionizable polycations, proteins would associate with anionic lipids, enabling microfluidic chip assembly of stable EP-LNPs (Encapsulated Proteins in Lipid NanoParticles). Here, by employing anionic lipids we were able to efficiently load proteins into EP-LNPs at protein:lipid w:w ratios of 1:20. Several proteins with diverse molecular weights and isoelectric points were encapsulated at efficiencies of 70 75%-90% and remained packaged for several months. Proteins packaged in EP-LNPs efficiently entered mammalian cells and fungal cells with cell walls. The proteins delivered intracellularly were functional. EP-LNPs technology should improve cellular delivery of medicinal antibodies, enzymes, peptide antimetabolites, and dominant negative proteins, opening new fields of protein therapeutics.

    PMID:41146908 | PMC:PMC12553553 | DOI:10.1038/s43246-025-00749-8

  • Anne Frances Jarrell wins 1st Place at the NAPB 2023 Poster Competition!

    Anne Frances Jarrell from the 2021 Cohort won first place for the PhD Poster Competition at the 2023 National Association of Plant Breeders meeting!

    In Spring 2022, Anne Frances officially joined the Robin Buell lab as a Graduate Research Assistant. She is interested in using advances in genomics to improve crop breeding, specifically to increase sustainability and crop resiliency in the face of global climate change. Currently, this leads her to work with potatoes and their wild relatives.

    Learn more about Anne Frances and her work by visiting the Buell Lab website!

    Congratulations Anne Frances!

  • Assessing UV-C radiation treatments for dollar spot suppression in seashore paspalum 

    Willis Turner Spratling

    Plant Dis. 2025 Dec 8. doi: 10.1094/PDIS-08-24-1610-RE. Online ahead of print.

    ABSTRACT

    Dollar spot, caused by Clarireedia spp., is one of the most detrimental diseases of turfgrass worldwide, and control strategies usually involve frequent fungicide applications. These treatments are expensive, require special equipment and can contribute to fungicide resistance issues, underscoring the need for alternative management strategies. UV-C radiation has proven effective as a disease management tool in various cropping systems but is still largely unexplored in turfgrass. This study aimed to test the effects of UV-C radiation against dollar spot in seashore paspalum and to evaluate its impact on plant health and performance. In assessing UV-C’s efficacy directly against C. monteithiana, daily radiation treatments ranging from 27.5 J m-2 to 77.0 J m-2 were shown to effectively reduce mycelial growth. Additionally, in vitro UV-C treatment administered in darkness was observed to be more effective in reducing pathogen growth than treatment administered in lighted conditions. In a growth chamber setting, daily 66.0 J m-2 UV-C treatment significantly reduced dollar spot severity in seashore paspalum without causing phytotoxic damage to plant tissues. In field trials, a novel UV-C application system was implemented by modifying a robotic mower to autonomously deliver UV-C radiation to seashore paspalum plots. UV-C treatment in the field significantly reduced dollar spot severity. Moreover, UV-C treatment led to several physiological and performance enhancements, including increased chlorophyll content, shoot density, surface firmness, and green speed. Findings from this study indicate that UV-C radiation may be used as an effective physical control to complement existing dollar spot management practices.

    PMID:41362131 | DOI:10.1094/PDIS-08-24-1610-RE

  • Biology, Ecology, and Management of Prevalent Thrips Species (Thysanoptera: Thripidae) Impacting Blueberry Production in the Southeastern United States 

    Rosan Adhikari

    Insects. 2025 Jun 24;16(7):653. doi: 10.3390/insects16070653.

    ABSTRACT

    Blueberry is a high-value fruit crop in the United States, with Georgia and Florida serving as important early-season production regions. In these areas, several thrips species (Thysanoptera: Thripidae), including Frankliniella tritici (Fitch), Frankliniella bispinosa (Morgan), and Scirtothrips dorsalis (Hood), have emerged as economically significant pests. While F. tritici and F. bispinosa primarily damage floral tissues, S. dorsalis targets young foliage. Their rapid reproduction, high mobility, and broad host range contribute to rapid population buildup and complicate the management programs. Species identification is often difficult due to overlapping morphological features and requires the use of molecular diagnostic tools for accurate identification. Although action thresholds, such as 2-6 F. tritici per flower cluster, are used to guide management decisions, robust economic thresholds based on yield loss remain undeveloped. Integrated pest management (IPM) practices include regular monitoring, cultural control (e.g., pruning, reflective mulch), biological control using Orius insidiosus (Say) and predatory mites, and chemical control. Reduced-risk insecticides like spinetoram and spinosad offer effective suppression while minimizing harm to pollinators and beneficial insects. However, the brief flowering period limits the establishment of biological control agents. Developing species-specific economic thresholds and phenology-based IPM strategies is critical for effective and sustainable thrips management in blueberry cropping systems.

    PMID:40725285 | DOI:10.3390/insects16070653

  • Bordetellae colonization oligosaccharide (b-Cool), a glycan crucial for nasal colonization 

    Yang Su

    Sci Adv. 2025 Sep 5;11(36):eadw7764. doi: 10.1126/sciadv.adw7764. Epub 2025 Sep 3.

    ABSTRACT

    Respiratory tract infections pose considerable global health challenges. Upper airway colonization is pivotal to these infections, including those caused by Bordetella species. We identified an oligosaccharide, bordetellae colonization oligosaccharide (b-Cool), crucial for early nasal colonization of Bordetella bronchiseptica. We characterized the structure of b-Cool by LC-MS and NMR and found that it is prevalent across a diverse range of bordetellae, including Bordetella pertussis, which causes whooping cough in humans. A B. bronchiseptica mutant lacking b-Cool (Δb-Cool) showed significantly delayed and decreased colonization in mouse nasopharynx and nasal epithelia, resulting in decreased transmission. The colonization defect of Δb-Cool was rescued in mucin deficient mice, suggesting that b-Cool may facilitate colonization in the presence of airway mucins.

    PMID:40901963 | DOI:10.1126/sciadv.adw7764

  • Building an expanded bio-based economy through synthetic biology 

    Andrea M Garza Elizondo

    Biotechnol Adv. 2025 Dec 6:108775. doi: 10.1016/j.biotechadv.2025.108775. Online ahead of print.

    ABSTRACT

    The field of synthetic biology is essential to the continued development of a bio-based economy, creating mechanisms to supply carbon needed in the economy by both converting existing end-of-life wastes as well as by creating novel, purpose-grown and sustainable feedstocks. Here, we first discuss the near- and long-term resources available for use as feedstocks for bioconversion as well as the output molecules needed for building the foundation of an expanded bio-based economy. We then outline the organisms and phenotypic traits that are needed for the performance-advantaged chassis organisms of the future. Furthermore, we detail the advances, challenges, and opportunities in both microbial and plant synthetic biology relevant to expanding the bio-based economy. Finally, we explore technologies that have and will further enable advances in synthetic biology and the greater bio-based economy.

    PMID:41360191 | DOI:10.1016/j.biotechadv.2025.108775

  • Building genomic resources to facilitate the study and use of Solanum microdontum, a wild relative of cultivated potato 

    Anne Frances Jarrell

    G3 (Bethesda). 2025 Oct 23:jkaf253. doi: 10.1093/g3journal/jkaf253. Online ahead of print.

    ABSTRACT

    Solanum microdontum Bitter is a diploid wild Andean relative of potato that has shaped the domestication and adaptation of modern cultivated potato to diverse environments. Solanum microdontum has the potential to provide a wealth of untapped genetic material for use in addressing current challenges in potato breeding. Here, we report a high-quality 772 Mb reference genome sequence for S. microdontum that is anchored to 12 chromosomes. The resulting genome assembly has 99.0% complete Benchmarking Universal Single Copy Orthologs and an N50 scaffold length of over 57 Mb, indicating a high level of completeness. Annotation of the assembly resulted in the identification of 37,324 protein coding genes and 65% repetitive sequence. A total of 1,187 nucleotide-binding leucine-rich repeat genes were predicted from the assembly, of which 93.1% overlapped an annotated high-confidence gene model. A k-mer based kinship matrix derived from a 107-member S. microdontum diversity panel revealed an underlying population structure that corresponds to geographic proximity. The S. microdontum dataset enhances publicly available potato genome resources by providing breeders with genetic, molecular, and germplasm resources for newly developed diploid potato breeding programs.

    PMID:41128648 | DOI:10.1093/g3journal/jkaf253

  • Candidate genes at the Rmi1 locus for resistance to Meloidogyne incognita in soybean 

    Kelly Goode

    Theor Appl Genet. 2025 Oct 29;138(11):286. doi: 10.1007/s00122-025-05065-w.

    ABSTRACT

    The RKN resistance locus Rmi1 was fine-mapped to two genes on chromosome 10, a glycosyl hydrolase family 9 β-1,4-endoglucanase gene and a type I pectin methylesterase gene. Root-knot nematodes (Meloidogyne spp.) are a serious threat to soybean production in the southeast USA, with yield losses of more than $165 million in 2023. Development and deployment of resistant soybean cultivars is the most effective strategy for managing these nematode pests; however, the identity of the resistance genes and underlying mechanism of resistance remains obscure. An additive resistance gene, Resistance to M. incognita-1 (Rmi1), to the predominant species, was first identified in soybean cultivar Forrest but never mapped to a genomic region. Multiple mapping studies have identified a major quantitative trait locus (QTL) with additive action on chromosome 10. In this study, a population consisting of 170 F2:3 families derived from a cross of Bossier (susceptible) × Forrest (resistant) was initially used to confirm that Rmi1 is in the chromosome 10 QTL. Subsequently, 884 F5:6 recombinant inbred lines (RILs) derived from the same cross were used to fine-map the Rmi1 causal gene(s) to two genes – a β-1,4-endoglucanase (Glyma.10G017000, EG) and a pectin methylesterase/methylesterase inhibitor (Glyma.10G017100, PME1). Both gene candidates have the potential to play a role in the resistance response to M. incognita. Both gene promoters harbor SNPs and indels and the encoded proteins exhibit amino acid polymorphisms, including a premature stop in PME1 of resistant soybeans. Additionally, both genes show a higher expression level in susceptible roots compared to resistant roots in the absence of infection. This suggests that Rmi1 may confer one or more pre-existing differences related to cell wall modification in soybean roots, ultimately leading to a decrease in susceptibility.

    PMID:41160124 | DOI:10.1007/s00122-025-05065-w

  • Celebrating the fifth edition of the International Symposium on Fungal Stress – ISFUS, a decade after its 2014 debut 

    Alene Alder-Rangel

    Fungal Biol. 2025 Aug;129(5):101590. doi: 10.1016/j.funbio.2025.101590. Epub 2025 May 6.

    ABSTRACT

    The Fifth International Symposium on Fungal Stress (ISFUS) brought together in Brazil many of the leaders in the field of fungal stress responses, from fourteen countries, for four days of outstanding science ranging from basic research to studies with agricultural, medical, industrial, and environmental significance. In addition to the excellent oral and poster presentations, the Symposium organisers ensured that all participants had ample opportunity to engage, socialise, and network to exchange ideas and share research. The conference was enhanced by the world-class venue near Iguazu Falls, probably the greatest natural phenomenon in South America.

    PMID:40707112 | DOI:10.1016/j.funbio.2025.101590

  • Characterization of Pseudomonas alliivorans strains isolated from Georgia, USA: insights into genomic diversity and pathogenicity in onions 

    Mei Zhao

    Appl Environ Microbiol. 2025 Nov 25:e0164325. doi: 10.1128/aem.01643-25. Online ahead of print.

    ABSTRACT

    Pseudomonas alliivorans is an important emerging pathogen affecting numerous crops. The species is closely related to Pseudomonas viridiflava, with which P. alliivorans strains were often misidentified in the past. Here, we investigated the genetic and pathogenic characteristics of P. alliivorans strains isolated primarily from onions and weeds in Georgia, USA, using whole-genome sequencing, comparative genomics, and functional assays. We delineated the core genome and genetic diversity of these isolates, assessed their pathogenicity on onion foliage and red onion scales, and examined the roles of key virulence determinants (Hrp1-type III secretion system [T3SS], rhizobium-T3SS, type II secretion systems [T2SSs], and thiosulfinate [allicin]-tolerance alt cluster). Our results showed that the Hrp1-T3SS is pivotal for pathogenicity in P. alliivorans, whereas the rhizobium-T3SS, T2SSs, and alt cluster do not contribute to symptom development on red onion scales. Notably, the alt cluster confers in vitro thiosulfinate tolerance, supporting bacterial survival against onion-derived antimicrobial compounds. Additionally, homologous recombination in P. alliivorans occurs infrequently (at approximately one-tenth the rate of point mutations) and involves divergent DNA segments. The alt cluster is acquired through horizontal gene transfer, as evidenced by its lower GC content and the presence of adjacent transposases. In summary, our research provides valuable insights into the genetic diversity, evolutionary dynamics, and virulence mechanisms of P. alliivorans strains from Georgia, USA.IMPORTANCEPseudomonas alliivorans is an emerging plant pathogen that threatens onion and other plants of economic importance. This study identifies key traits that help this bacterium cause disease, such as a specific secretion system critical for infecting onions, and a gene cluster that aids bacterial survival in onion tissues. Beyond highlighting weed as a potential inoculum source and supporting better weed management, the findings of this research open avenues for more targeted disease menegement. By unraveling the genetics of this pathogen, we can develop improved ways to detect, prevent, and reduce its impact, protecting crop health and yields.

    PMID:41288358 | DOI:10.1128/aem.01643-25

  • Comparative Analyses of Four Reference Genomes Reveal Exceptional Diversity and Weak Linked Selection in the Yellow Monkeyflower (Mimulus guttatus) Complex 

    John T Lovell

    Mol Ecol Resour. 2025 Jul 22:e70012. doi: 10.1111/1755-0998.70012. Online ahead of print.

    ABSTRACT

    Yellow monkeyflowers (Mimulus guttatus complex, Phrymaceae) are a powerful system for studying ecological adaptation, reproductive variation, and genome evolution. To initiate pan-genomics in this group, we present four chromosome-scale assemblies and annotations of accessions spanning a broad evolutionary spectrum: two from a single M. guttatus population, one from the closely related selfing species M. nasutus, and one from a more divergent species M. tilingii. All assemblies are highly complete and resolve centromeric and repetitive regions. Comparative analyses reveal such extensive structural variation in repeat-rich, gene-poor regions that large portions of the genome are unalignable across accessions. As a result, this Mimulus pan-genome is primarily informative in genic regions, underscoring limitations of resequencing approaches in such polymorphic taxa. We document gene presence-absence, investigate the recombination landscape using high-resolution linkage data, and quantify nucleotide diversity. Surprisingly, pairwise differences at fourfold synonymous sites are exceptionally high-even in regions of very low recombination-reaching ~3.2% within a single M. guttatus population, ~7% within the interfertile M. guttatus species complex (approximately equal to SNP divergence between great apes and Old World monkeys), and ~7.4% between that complex and the reproductively isolated M. tilingii. Genome-wide patterns of nucleotide variation show little evidence of linked selection, and instead suggest that the concentration of genes (and likely selected sites) in high-recombination regions may buffer diversity loss. These assemblies, annotations, and comparative analyses provide a robust genomic foundation for Mimulus research and offer new insights into the interplay of recombination, structural variation, and molecular evolution in highly diverse plant genomes.

    PMID:40693537 | DOI:10.1111/1755-0998.70012

  • Comparative Transcriptomic Analysis of Soybean Recombinant Inbred Lines Differing at the Rmi1 Locus for Resistance to Meloidogyne incognita During Early Stages of Nematode Infection 

    Kelly Goode

    Phytopathology. 2025 Jun 11. doi: 10.1094/PHYTO-04-25-0143-SC. Online ahead of print.

    ABSTRACT

    Root-knot nematodes (Meloidogyne spp.) are a continuing threat to soybean production, with M. incognita being the predominant species. The deployment of Mi-resistant soybean cultivars is a primary management strategy, but the underlying molecular mechanisms contributing to resistance remain unknown. A single, additive gene for resistance to M. incognita, Rmi1, was previously identified in soybean cv. Forrest and associated with the emigration of second-stage juveniles from the roots. To better understand the Rmi1-mediated resistance response, we used Forrest-derived F5 RILs differing for Rmi1 to analyze global changes in gene expression in response to M. incognita infection at 2- and 4-days post inoculation. We identified 1,471 differentially expressed (DE) genes in the compatible interaction and 1,037 DE genes in the incompatible interaction. Forty-five percent of DE genes were DE in both interactions, 42% (856) were unique to the compatible interaction, and 13% (261) were unique to the incompatible interaction. Genes uniquely DE in the incompatible interaction included genes involved in cell wall modification, hormone signaling, endomembrane trafficking, and redox reactions providing new insights into the resistance mechanism mediated by Rmi1 in soybean to root-knot nematodes.

    PMID:40498525 | DOI:10.1094/PHYTO-04-25-0143-SC

  • Conflicting kinesin-14s in a single chromosomal drive haplotype 

    Author: Kelly Dawe

    Genetics. 2025 May 14:iyaf091. doi: 10.1093/genetics/iyaf091. Online ahead of print.

    ABSTRACT

    In maize, there are two meiotic drive systems that target large heterochromatic knobs composed of tandem repeats known as knob180 and TR-1. The first meiotic drive haplotype, Abnormal chromosome 10 (Ab10) confers strong meiotic drive (∼75% transmission as a heterozygote) and encodes two kinesins: KINDR, which associates with knob180 repeats and TRKIN, which associates with TR-1 repeats. Prior data show that meiotic drive is conferred primarily by the KINDR/knob180 system while the TRKIN/TR-1 system seems to have little or no role, making it unclear why Trkin has been maintained in Ab10 haplotypes. The second meiotic drive haplotype, K10L2, confers a low level of meiotic drive (∼51-52%) and only encodes the TRKIN/TR-1 system. Here we used long-read sequencing to assemble the K10L2 haplotype and showed that it has strong homology to an internal portion of the Ab10 haplotype. We also carried out CRISPR mutagenesis to test the role of Trkin on Ab10 and K10L2. The data indicate that the Trkin gene on Ab10 does not improve drive or fitness but instead has a weak deleterious effect when paired with a normal chromosome 10. The deleterious effect is more severe when Ab10 is paired with K10L2: in this context functional Trkin on either chromosome nearly abolishes Ab10 drive. Mathematical modeling based on the empirical data suggest that Trkin is unlikely to persist on Ab10. We conclude that Trkin either confers an advantage to Ab10 in untested circumstances or that it is in the process of being purged from the Ab10 population.

    PMID:40365704 | DOI:10.1093/genetics/iyaf091

  • Correction: Drought adaptation index (DAI) based on BLUP as a selection approach for drought-resilient switchgrass germplasm 

    Shiva Om Makaju

    Front Genet. 2025 Nov 12;16:1731825. doi: 10.3389/fgene.2025.1731825. eCollection 2025.

    ABSTRACT

    [This corrects the article DOI: 10.3389/fgene.2025.1626083.].

    PMID:41311856 | PMC:PMC12648043 | DOI:10.3389/fgene.2025.1731825

  • Cross-resistance in Alternaria brassicicola from naturally infested broccoli seeds against two succinate dehydrogenase inhibitor fungicides 

    Navjot Kaur

    Appl Environ Microbiol. 2025 Sep 4:e0108325. doi: 10.1128/aem.01083-25. Online ahead of print.

    ABSTRACT

    Seeds can serve as a vehicle for the dissemination of pests and pathogens around the world. We recently demonstrated the association of pathogenic Alternaria brassicicola isolates with reduced sensitivity to azoxystrobin (quinone-outside inhibitor [QoI]) in naturally infested commercial broccoli seeds. In this study, we further demonstrate that these isolates were also resistant to two succinate dehydrogenase inhibitor (SDHI) fungicides. Sensitivity of representative A. brassicicola isolates (n = 58) from naturally infested broccoli seedlots to QoI and SDHI fungicides was evaluated under in vitro conditions. Interestingly, 15% (n = 9/58) of the A. brassicicola isolates with reduced sensitivity to azoxystrobin also displayed reduced sensitivity to two commonly used SDHI fungicides (boscalid and penthiopyrad) in broccoli, indicating a potential case of cross-resistance to SDHI fungicides. Ninety-three percent of the isolates (n = 54/58) were resistant to both boscalid and penthiopyrad, while 100% isolates displayed sensitivity to fluopyram. Sequence analysis of sdh genes revealed the presence of only one point mutation (H134R) in the sdhC gene in isolates that displayed resistance to boscalid and penthiopyrad. We also developed and validated allele-specific primers targeting the H134R mutation for rapid screening of SDHI resistance in A. brassicicola. We also found that boscalid-resistant isolates exhibited significantly reduced mycelial growth. However, spore germination rates among different resistant isolates were not different, suggesting that resistant isolates remain competitive in natural populations. Overall, this study provides the first evidence of fungicide resistance to SDHI fungicides in A. brassicicola isolated from naturally infested broccoli seeds and underscores the importance of seeds as a potential source for introducing fungicide resistance across geographical locations.

    IMPORTANCE: Alternaria brassicicola is a fungal seed-borne pathogen that can be disseminated via commercial seeds across transplant houses and commercial broccoli fields. Our study provides the first evidence that commercial broccoli seeds can harbor pathogenic A. brassicicola isolates with cross-resistance to two succinate dehydrogenase inhibitor (SDHI) fungicides. We observed that 93% of the A. brassicicola isolates from naturally infested commercial broccoli seeds contained a point mutation that conferred resistance to two SDHI fungicides (boscalid and penthiopyrad). Furthermore, we developed a PCR-based allele-specific assay for the rapid detection and monitoring of fungicide resistance. Our study highlights the importance of seed health testing and potential dissemination of fungicide-resistant isolates locally and globally, thus impacting disease management strategies.

    PMID:40905662 | DOI:10.1128/aem.01083-25

  • Deciphering the Biochemical Functions and Nucleotide Sugar Donor Specificity Determinants of Dicot GT61 Glycosyltransferases Involved in Xylan Substitutions 

    Ruiqin Zhong

    Plant Cell Physiol. 2025 Sep 26:pcaf122. doi: 10.1093/pcp/pcaf122. Online ahead of print.

    ABSTRACT

    Plant cell wall polysaccharide glycosyltransferases catalyze the transfer of sugars from specific nucleotide sugar donors onto specific acceptor substrates. The mechanisms of how their enzymatic specificity is determined is one of the long-standing questions in plant cell wall biology. In this report, we studied the biochemical functions of Arabidopsis and poplar GT61 glycosyltransferases involved in xylan substitutions and investigated the molecular determinants of their nucleotide sugar donor specificity. Enzymatic activity assays of recombinant proteins of Arabidopsis and poplar GT61 members demonstrated that two of them, AtX2AT1 and PtrX2AT1, exhibited xylan 2-O-arabinosyltransferase activities specifically using UDP-Araf, two other ones, AtXYXT2/3, possessed xylan 2-O-xylosyltransferase activities specifically using UDP-Xyl, and three other ones, PtrXXAT1/2/3, were able to catalyze the transfer of 2-O-Araf and 2-O-Xyl onto xylan using both UDP-Araf and UDP-Xyl. Structural modeling and molecular docking of PtrXXAT1 identified amino acid residues involved in interacting with UDP-Araf and UDP-Xyl at the putative active site and site-directed mutagenesis revealed their critical roles in PtrXXAT1 catalytic activities. Furthermore, structural alignment and reciprocal swapping of UDP-Xyl-interacting residues of PtrXXAT1 with their corresponding residues of AtX2AT1 pinpointed key residues determining their nucleotide sugar donor specificity. Our results indicate that Arabidopsis and poplar GT61 members catalyze 2-O-Araf- and/or 2-O-Xyl substitutions of xylan and that subtle structural differences in their substrate-binding pockets could alter their substrate specificity toward nucleotide sugar donors.

    PMID:41001967 | DOI:10.1093/pcp/pcaf122

  • Design of genus-specific semi-nested primers for simple and accurate identification of Enterobacter strains 

    Sara Jordan

    BMC Microbiol. 2025 Jul 28;25(1):456. doi: 10.1186/s12866-025-04175-1.

    ABSTRACT

    BACKGROUND: The genus Enterobacter, in the family Enterobacteriaceae, is of both clinical and environmental importance. This genus has undergone frequent taxonomic changes, making it challenging to identify taxa even at genus level. This study aimed to design Enterobacter genus-specific primers that can be used for simple PCR identification of large sets of putative Enterobacter isolates.

    RESULTS: Comparative genomic approaches were employed to identify genes that were universally present on Enterobacter genomes but absent from the genomes of other members of the family Enterobacteriaceae, based on an initial set of 89 genomes. The presence of these genes was further confirmed in 4,276 Enterobacter RefSeq genomes. While no strictly genus-specific genes were identified, the hpaB gene demonstrated a restricted distribution outside of the genus Enterobacter. Semi-nested primers were designed for hpaB and its flanking gene hpaC (hpaBC) and evaluated on 123 strains in single-tube PCR reactions. All taxa showing positive reactions belonged to the genus Enterobacter. For Enterobacter strains the PCR yielded two amplicons at 110 bp and at 370 bp, while strains only displaying the 110 bp amplicon were classified as Leclercia pneumoniae. A blind-test on 120 strains accessioned as Enterobacter sp. from the USDA-ARS culture collection (NRRL), revealed that one third of the strains had an incorrect genus assignment. Comparison of gene trees of the hpaBC fragment sequences with marker genes frequently used for single-gene barcoding or multi-locus sequence analysis (MLSA) further demonstrated its potential for preliminary species identification.

    CONCLUSIONS: The nested PCR assay represents a rapid and cost-effective approach for preliminary identification of Enterobacter species. As the primer design was based on large-scale genomic comparison, including currently undescribed species clades, it will remain valid even after taxonomic changes within the genus.

    PMID:40722002 | DOI:10.1186/s12866-025-04175-1

  • Detection of the gummy stem blight pathogens (Stagonosporopsis spp.) in watermelon using field-adapted LAMP assays and rapid DNA extraction protocols 

    Jorge Alberto Reyes Pineda

    Plant Dis. 2025 Aug 6. doi: 10.1094/PDIS-12-24-2589-SR. Online ahead of print.

    ABSTRACT

    Gummy stem blight (GSB), caused by three Stagonosporopsis species, S. citrulli, S. cucurbitacearum and S. caricae, is one of the most economically important diseases hindering watermelon production worldwide. Since there is no commercial resistance to GSB in watermelon cultivars, its management depends on cultural practices and preventative fungicides. Therefore, efficient methods for the detection of Stagonosporopsis species that could aid management decisions are required. To help achieve this, a loop-mediated isothermal amplification (LAMP) assay specific to S. citrulli (SCIT850) was developed under two detection formats: fluorescence quantification and endpoint colorimetric detection. The SCIT850 assay was determined to be specific to its target species and exhibited a consistent sensitivity of 1 pg of genomic DNA under both formats. The assay can be combined with a previously reported LAMP assay for the collective detection of the three Stagonosporopsis spp. (STAGY), which have comparable sensitivity to SCIT850 and can aid in species discrimination. A field diagnostic system for GSB-causing Stagonosporopsis was developed by coupling the SCIT850 and STAGY assays to quick DNA extraction protocols. Two DNA extraction methods were tested: one from leaves using cellulose dipsticks, and one from steel rods (typical of spore traps) using Chelex100. With the dipstick method, we detected pathogen DNA in inoculated asymptomatic, mildly infected, and severely infected plants, while with the Chelex100 we detected pathogen DNA from rods infested with as few as 500 spores. The SCIT850 and STAGY assays coupled with these quick sample processing methods could be adapted for field deployment, which would allow growers to make efficient and timely management decisions based on detection of the actual Stagonosporopsis species present in the field.

    PMID:40767855 | DOI:10.1094/PDIS-12-24-2589-SR

  • Determining the causal agents of Alternaria leaf blight and head rot affecting broccoli in the Eastern United States 

    Roy L Davis

    Plant Dis. 2025 May 22. doi: 10.1094/PDIS-01-25-0117-SR. Online ahead of print.

    ABSTRACT

    Alternaria brassicicola is the causal agent typically associated with Alternaria leaf blight and head rot (ABHR) disease in broccoli and related crops in the Eastern United States. Recently a new species, A. japonica, has been reported as causing disease in broccoli and other vegetables in this region. We conducted a multi-state pathogen survey during the growing seasons of 2022 and 2023 to assess the distribution and occurrence of A. japonica in relation to A. brassicicola in five broccoli-producing states. Our approach specifically targeted collection of broccoli leaves with lesions typical of ABHR within commercially grown fields managed using either organic or conventional approaches in Connecticut, Massachusetts, New York, Virginia, and Georgia. Only typical ABHR leaf lesions were selected for pathogen isolation and, subsequently, sequencing of the Alternaria major allergen a1 gene was used to identify Alternaria species. The predominant species isolated was A. brassicicola (88% in 2022 and 94% in 2023) and the second most common was A. alternata (12% in 2022 and 6% in 2023), which was obtained from fields in Connecticut and Massachusetts in 2022, and in Virginia in both years. Alternaria japonica was not found in either year. Symptoms of A. alternata were indistinguishable from A. brassicicola, as were colony morphologies. While A. alternata is considered a generalist and of little consequence for broccoli, it is considered a pathogen of significance on multiple crops (blueberry, citrus, pistachios), but there remains scant information on the disease etiology on broccoli. Therefore, we inoculated broccoli with A. alternata in controlled conditions in order to shed light on possible differences in infectivity of these species on broccoli. Results of our study showed that A. alternata is pathogenic on broccoli, capable of initiating infection and causing lesions typical of ABHR. This indicates that future disease surveys of ABHR should conclusively identify species of Alternaria that are causing disease. Additional research is needed to determine the significance of this finding in relation to yield impacts, epidemiology, fungicide resistance, and management recommendations.

    PMID:40403277 | DOI:10.1094/PDIS-01-25-0117-SR

  • Discovering leaf and stripe rust resistance in soft red winter wheat through genome-wide association studies 

    John W Bagwell

    Plant Genome. 2025 Jun;18(2):e70055. doi: 10.1002/tpg2.70055.

    ABSTRACT

    Leaf rust (LR) and stripe rust (YR), which are caused by Puccinia triticina and Puccinia striiformis, respectively, are among the most devastating wheat rusts worldwide. These diseases can be managed by using genetically resistant cultivars, an economical and environmentally safer alternative to fungicides. Over 100 and 80 Lr and Yr resistance genes have been discovered, respectively; however, rust pathogens are overcoming introduced resistance genes in the southeastern United States. Genome-wide association study has emerged as a valuable tool to identify new LR and YR resistance loci. In this study, a panel of 263 soft red winter wheat genotypes was evaluated for LR and YR severity in Plains, GA, and Williamson, GA, in a randomized complete block design of two replicates during 2019 and 2021-2023. Also, LR and YR infection types were assessed on seedlings at the three leaf stage in three greenhouse trials. A total of 26 significant quantitative trait loci (QTL) explaining 0.6%-30.8% phenotypic variance (PV) was detected by at least two of the five GAPIT models (BLINK, CMLM, FarmCPU, GLM, and MLM) tested. Nine major QTL included QLrYr-2A.1 linked to single-nucleotide polymorphism S2A_20855466, which had the highest overall PV (30.8%) for response to both rust pathogens in the field. Using the Chinese Spring Reference Genome Version 1.0, we detected 16 candidate genes, and four known R genes and QTL overlapped two major QTL. Of these QTL, 16 are likely novel genetic loci with potential for marker-assisted selection.

    PMID:40495572 | DOI:10.1002/tpg2.70055

  • Discovery of iridoid cyclase completes the iridoid pathway in asterids 

    Maite Colinas

    Nat Plants. 2025 Oct 3. doi: 10.1038/s41477-025-02122-6. Online ahead of print.

    ABSTRACT

    Iridoids are specialized monoterpenes ancestral to asterid flowering plants1,2 that play key roles in defence and are also essential precursors for pharmacologically important alkaloids3,4. The biosynthesis of all iridoids involves the cyclization of the reactive biosynthetic intermediate 8-oxocitronellyl enol. Here, using a variety of approaches including single-nuclei sequencing, we report the discovery of iridoid cyclases from a phylogenetically broad sample of asterid species that synthesize iridoids. We show that these enzymes catalyse formation of 7S-cis-trans and 7R-cis-cis nepetalactol, the two major iridoid stereoisomers found in plants. Our work uncovers a key missing step in the otherwise well-characterized early iridoid biosynthesis pathway in asterids. This discovery unlocks the possibility to generate previously inaccessible iridoid stereoisomers, which will enable metabolic engineering for the sustainable production of valuable iridoid and iridoid-derived compounds.

    PMID:41044409 | DOI:10.1038/s41477-025-02122-6

  • Dr. Diane Okamuro Gather & Grow Webinar

    Gather & Grow Webinar: What is it Like to be a Program Manager at NSF?

    Dr. Diane Okamuro, National Science Foundation Program Manager

    April 17, 2025 | Noon – 1PM

    Join Zoom

     

    Dr. Diane Jofuku Okamuro is a Program Director for the Plant Genome Research Program (PGRP) at the National Science Foundation, Directorate for Biological Sciences (BIO), Division of Integrative Organismal Systems. The PGRP is broad in scope and supports functional genomics tool development and basic discovery research on a genome-wide scale that will provide new insights into plant processes that are important to the U.S. economy. The PGRP Cluster also manages the Plant Genome Research Postdoctoral Fellowships program which is part of the BIO-wide Postdoctoral Research Fellowships in Biology program. In addition, she currently serves on the Working Group for the Biology Integration Institutes (BII) program which supports interdisciplinary, collaborative teams that perform research, education and training on critical questions that span multiple disciplines within and beyond biology.
    Dr. Okamuro received her Ph.D. in Biology from UCLA and is a plant molecular geneticist by training. She has broad-based experience in cutting-edge functional genomics technologies and has held research and management positions in both academia and industry prior to joining NSF in 2005.

  • Dr. Donglin Zhang recently named a 2024 Plant Biotechnology Fellow by the American Society for Horticultural Sciences!

    Congratulations to Dr. Donglin Zhang for recently being named a 2024 Plant Biotechnology Fellow by the American Society for Horticultural Sciences!

    Fellows of the Society are recognized for outstanding contributions to horticulture in one or more of the following areas: research, teaching, administration, or extension on a state, national, and/or international level; exhibition of leadership in horticultural business or industry pertinent to and compatible with the objectives of the Society; and noteworthy contributions to ASHS objectives (“to promote and encourage national and international interest in scientific research and education in horticulture in all its branches”). This may be demonstrated by the nominee’s direct and effective participation in the affairs and activities of the Society (including its Regional Groups) and/or by active involvement in the affairs of other allied organizations having objectives essentially the same as those of ASHS (including international organizations and those in countries other than the United States).

    Election as a Fellow of the Society is the highest honor that ASHS can bestow on its members, in recognition of truly outstanding contributions to horticulture and the Society.

    Congratulations, Dr. Zhang!

  • Dr. Rishi Masalia Gather & Grow Webinar

  • Draft genome assemblies of 38 Aspergillus parasiticus isolates collected from South Georgia crop fields 

    Sunil S Gangurde

    Microbiol Resour Announc. 2025 Sep 12:e0008325. doi: 10.1128/mra.00083-25. Online ahead of print.

    ABSTRACT

    Aspergillus parasiticus is a fungus recognized for producing highly carcinogenic mycotoxins. In this study, we collected 38 isolates of A. parasiticus from fields in South Georgia. We performed whole genome re-sequencing and developed 38 draft genome assemblies of A. parasiticus. The average genome size was 38.7 Mb, with larger genomes (~40 Mb) found in peanut fields in Turner County. Scaffold N50 was recorded highest for isolates collected from the corn fields of Tifton. The average BUSCO completeness score for these assemblies was 99.1%. The genome sequences generated for these 38 isolates will serve as a valuable genomic resource for the community working on aflatoxin mitigation strategies in crops.

    PMID:40938094 | DOI:10.1128/mra.00083-25

  • Drought adaptation index (DAI) based on BLUP as a selection approach for drought-resilient switchgrass germplasm 

    Shiva Om Makaju

    Front Genet. 2025 Aug 25;16:1626083. doi: 10.3389/fgene.2025.1626083. eCollection 2025.

    ABSTRACT

    This study introduces a Drought Adaptation Index (DAI), derived from Best Linear Unbiased Prediction (BLUP), as a method to assess drought resilience in switchgrass (Panicum virgatum L.). A panel of 404 genotypes was evaluated under drought-stressed (CV) and well-watered (UC) conditions over four consecutive years (2019-2022). BLUP-estimated biomass yields were used to calculate the DAI, which enabled classification of genotypes into four adaptation groups: very well-adapted, well-adapted, adapted, and unadapted. The DAI was compared with conventional drought tolerance indices, including the Stress Susceptibility Index (SSI), Stress Tolerance Index (STI), Geometric Mean Productivity (GMP), and Yield Stability Index (YSI). Correlation analyses demonstrated strong agreement between DAI and these indices, supporting its validity and consistency. Biplot analyses using the Genotype plus Genotype-by-Environment Interaction (GGE) and Additive Main Effects and Multiplicative Interaction (AMMI) models revealed significant genotype-by-environment interactions (GEI) and identified J222.A, J463.A, and J295.A. A as high-performing genotypes, with J222.A exhibiting greater yield stability across treatments and years. Additionally, DAI isoline curves provided a graphical representation of differential genotype performance under drought and control conditions. These visualizations aided in distinguishing genotypes with stable and superior biomass yield across contrasting environments. Overall, the BLUP-based DAI is a robust and practical selection tool that improves the accuracy of identifying drought-resilient, high-yielding switchgrass genotypes. Its integration into breeding programs offers a comprehensive framework for improving biomass productivity and stress adaptation under variable climatic conditions. The application of DAI supports the development of climate-resilient cultivars and contributes to sustainable bioenergy and forage production systems.

    PMID:40927363 | PMC:PMC12414770 | DOI:10.3389/fgene.2025.1626083

  • Engineering chromosome number in plants 

    Feng Zhang

    Science. 2025 Nov 20;390(6775):786-787. doi: 10.1126/science.aec7902. Epub 2025 Nov 20.

    ABSTRACT

    Chromosome engineering produces a reduced eight-chromosome karyotype in Arabidopsis thaliana.

    PMID:41264719 | DOI:10.1126/science.aec7902

  • Enzymatic epimerization of monoterpene indole alkaloids in kratom 

    Allwin McDonald

    Nat Chem Biol. 2025 Jul 16. doi: 10.1038/s41589-025-01970-9. Online ahead of print.

    ABSTRACT

    Monoterpene indole alkaloids (MIAs) are a large, structurally diverse class of bioactive natural products. These compounds are biosynthetically derived from a stereoselective Pictet-Spengler condensation that generates a tetrahydro-β-carboline scaffold characterized by a 3S stereocenter. However, a subset of MIAs contains a noncanonical 3R stereocenter. Here we report the basis for 3R-MIA biosynthesis in Mitragyna speciosa (kratom). We discover the presence of the iminium species (20S)-3-dehydrocorynantheidine, which supports isomerization of 3S to 3R via oxidation and stereoselective reduction downstream of the initial Pictet-Spengler condensation. Isotopologue feeding experiments identify the sites for downstream MIA pathway biosynthesis as well as the oxidase/reductase pair that catalyzes this epimerization. This oxidase/reductase pair has broad substrate specificity, suggesting that this pathway may be responsible for the formation of many 3R-MIAs and downstream spirooxindole alkaloids in kratom. The elucidation of this epimerization mechanism allows biocatalytic access to a range of pharmacologically active spirooxindole alkaloid compounds.

    PMID:40670688 | DOI:10.1038/s41589-025-01970-9

  • Estimating Hospitalization Expenditures Associated with Chronic Diseases and Multimorbidity for Older Adults – Guangzhou City, Guangdong Province, China, 2017-2019 

    Fei Zhao

    China CDC Wkly. 2025 Aug 1;7(31):1031-1037. doi: 10.46234/ccdcw2025.175.

    ABSTRACT

    WHAT IS ALREADY KNOWN ABOUT THIS TOPIC?: Chronic diseases and multimorbidity impose substantial burdens on healthcare systems globally, particularly in aging populations, resulting in elevated healthcare utilization rates and increased expenditures.

    WHAT IS ADDED BY THIS REPORT?: This study validates previous research findings using an extensive administrative database from a major city in South China. Additionally, it provides comprehensive estimates of annual hospitalization expenditures per patient associated with chronic diseases and multimorbidity patterns among older adults, elucidating the economic burden and cost variations across specific diseases and multimorbidity combinations. Cancer, cerebrovascular disease (CVD), and heart disease – whether occurring individually or in conjunction with other chronic conditions, particularly within complex multimorbidity patterns – were associated with substantial annual hospitalization expenditures and significant healthcare resource utilization.

    WHAT ARE THE IMPLICATIONS FOR PUBLIC HEALTH PRACTICE?: Disease burden studies provide critical evidence for prioritizing public health policies and targeted interventions. Policymakers should implement comprehensive prevention strategies, evidence-based interventions, appropriate reimbursement policies, and integrated management approaches to control disease progression and reduce healthcare expenditures.

    PMID:40831617 | PMC:PMC12360313 | DOI:10.46234/ccdcw2025.175

  • Ethylene-releasing plant growth regulators promote ripening initiation by stimulating sugar, acid and anthocyanin metabolism in blueberry (Vaccinium ashei) 

    Tej P Acharya

    BMC Plant Biol. 2025 Jun 5;25(1):766. doi: 10.1186/s12870-025-06799-x.

    ABSTRACT

    BACKGROUND: Fruit ripening is a coordinated process that leads to an increase in sugars, decrease in acids and accumulation of pigments. Blueberry fruit exhibit an atypical climacteric ripening behavior. These fruit display an increase in respiration and ethylene production during ripening, however ethylene synthesis is developmentally regulated. In this study, the effect of ethylene on blueberry fruit ripening was investigated via preharvest applications of ethylene-releasing plant growth regulators (PGRs), ethephon and 1-aminocyclopropane 1-carboxylic acid (ACC), in one southern highbush cultivar, Miss Lilly in 2019, and two rabbiteye cultivars, Premier and Powderblue in 2019 and 2020. Further, the effects of these two PGRs on fruit metabolism during ripening in the two rabbiteye cultivars, and postharvest fruit quality in all three cultivars were evaluated.

    RESULTS: Both PGRs increased ethylene evolution within 1-3 days after treatment (DAT). Ethephon and ACC applications increased the rate of ripening within 5 DAT in all cultivars, and increased ripe (blue) fruit by up to 35% and 29%, respectively between 7 to 10 DAT compared to the control. Metabolite analysis revealed that PGR treatments resulted in an immediate, but transient increase in sucrose, glucose and fructose, in ‘Premier’ at 3 DAT. Malate decreased at 3 DAT in response to both PGR treatments in ‘Premier’, and at 5 DAT in ethephon treatment in both cultivars. A rapid increase in the concentration of multiple anthocyanins was noted at 3 DAT in response to both PGRs in ‘Premier’ and ‘Powderblue’. Gene expression analysis revealed an increase in transcript abundance of VACUOLAR INVERTASE (vINV) and multiple anthocyanin biosynthesis genes between 1 and 3 DAT after PGR treatments in both cultivars, supporting the metabolite changes. However, the alteration in fruit metabolite concentrations were not sustained, and similar in PGR-treated fruit compared to the control in ripe fruit harvested at 10 DAT. Postharvest fruit quality attributes, such as firmness, total soluble solids, titratable acidity, and visual quality, were not consistently affected by the PGR applications compared to control treatments across all cultivars. A decrease in fruit weight was noted, although not consistently, in response to PGR treatments.

    CONCLUSIONS: Overall, this study demonstrates that ethylene plays a crucial role in promoting ripening via rapid and transient stimulation of sugar, acid and anthocyanin metabolism. The promotion of fruit ripening by ethylene-releasing PGRs can lead to minimal but inconsistent changes in fruit quality attributes during postharvest storage.

    PMID:40474063 | DOI:10.1186/s12870-025-06799-x

  • Evaporative cooling signals for wound healing in plants 

    Joseph Balem

    bioRxiv [Preprint]. 2025 May 28:2025.05.23.655667. doi: 10.1101/2025.05.23.655667.

    ABSTRACT

    Repairing a damaged body part is critical for the survival of any organism. In plants, tissue damage induces rapid responses that activate defense, regeneration and wound healing. While early wound signaling mediated by phytohormones, electrical signals and reactive oxygen species is well-characterized, the mechanisms governing the final stages of wound healing remain poorly understood. Here, we show that wounding in Arabidopsis leaves induces localized cooling, likely due to evaporative water loss, accompanied by the activation of cold-responsive genes. The subsequent disappearance of localized cooling and deactivation of cold-responsive genes serve as a quantitative marker of wound healing. Based on these observations, we developed a workflow by leveraging computer vision and deep learning to monitor the dynamics of wound healing. We found that CBFs transcription factors relay injury-induced cooling signal to wound healing. Thus, our work advances our understanding of tissue repair and provides a tool to quantify wound healing in plants.

    PMID:40502075 | PMC:PMC12154623 | DOI:10.1101/2025.05.23.655667

  • Everyday norms have become more permissive over time and vary across cultures 

    Kimmo Eriksson

    Commun Psychol. 2025 Oct 7;3(1):145. doi: 10.1038/s44271-025-00324-4.

    ABSTRACT

    Every social situation that people encounter in their daily lives comes with a set of unwritten rules about what behavior is considered appropriate or inappropriate. These everyday norms can vary across societies: some societies may have more permissive norms in general or for certain behaviors, or for certain behaviors in specific situations. In a preregistered survey of 25,422 participants across 90 societies, we map societal differences in 150 everyday norms and show that they can be explained by how societies prioritize individualizing moral foundations such as care and liberty versus binding moral foundations such as purity. Specifically, societies with more individualistic morality tend to have more permissive norms in general (greater liberty) and especially for behaviors deemed vulgar (less purity), but they exhibit less permissive norms for behaviors perceived to have negative consequences in specific situations (greater care). By comparing our data with available data collected twenty years ago, we find a global pattern of change toward more permissive norms overall but less permissive norms for the most vulgar and inconsiderate behaviors. This study explains how social norms vary across behaviors, situations, societies, and time.

    PMID:41057696 | DOI:10.1038/s44271-025-00324-4

  • Factors underlying a latitudinal gradient in the S/G lignin monomer ratio in natural poplar variants 

    Weiwei Zhu

    Proc Natl Acad Sci U S A. 2025 Aug 26;122(34):e2503491122. doi: 10.1073/pnas.2503491122. Epub 2025 Aug 20.

    ABSTRACT

    The chemical composition of wood plays a pivotal role in the adaptability and structural integrity of trees. However, few studies have investigated the environmental factors that determine lignin composition and its biological significance in plants. Here, we examined the lignin syringyl-to-guaiacyl (S/G) ratio in members of a Populus trichocarpa population sourced from their native habitat and conducted a genome wide association study to identify genes linked to lignin formation. Our results revealed many significant associations, suggesting that lignin biosynthesis is a complex polygenic trait. Additionally, we found an increase in the S/G ratio from northern to southern geographic origin of the trees sampled, along with a corresponding metabolic and transcriptional reprogramming of xylem cell wall biosynthesis. Further molecular analysis identified a mutation in a cell wall laccase genetically associated with higher S/G ratios that predominate in trees from warmer lower latitudes. Collectively, our findings suggest that lignin heterogeneity arises from an evolutionary process enabling poplar adaptation to different climatic challenges.

    PMID:40833412 | DOI:10.1073/pnas.2503491122

  • FFAR Announces 26 Awardees of FFAR Fellows Program naming Shreena Pradhan

    WASHINGTON (August 11, 2021) – Climate change, a growing population and evolving pests and pathogens threaten the security of our global food supply. Employers need trained scientists to conduct research that helps farms and food systems adapt to these challenges. The Foundation for Food & Agriculture Research (FFAR) and North Carolina State University are excited to announce the 26 students selected for the 2021 FFAR Fellows Program. This unique three-year program provides professional development training and mentorship to doctoral students conducting research in alignment with FFAR’s six Challenge Areas.

  • FX-Cell: a method for single-cell RNA sequencing on difficult-to-digest and cryopreserved plant samples 

    Xin Ming

    Nat Methods. 2025 Nov 27. doi: 10.1038/s41592-025-02900-2. Online ahead of print.

    ABSTRACT

    Single-cell RNA sequencing in plants requires the isolation of high-quality protoplasts-cells devoid of cell walls. However, many plant tissues and organs are resistant to enzymatic digestion, posing a significant barrier to advancing single-cell multi-omics in plant research. Furthermore, for field-grown crops, the lack of immediate laboratory facilities presents another major challenge for timely protoplast preparation. Here, to address these limitations, we developed FX-Cell and its derivatives, FXcryo-Cell and cryoFX-Cell, to enable single-cell RNA sequencing with both difficult-to-digest and cryopreserved plant samples. By optimizing the fixation buffer and minimizing RNA degradation, our approach ensures efficient cell wall digestion at high temperatures while maintaining high-quality single cells, even after long-term storage at -80 °C, and circumvents use of nuclei, which are not representative of the pool of translatable messenger RNAs. We successfully constructed high-quality cell atlases for rice tiller nodes, rhizomes of wild rice and maize crown roots grown under field conditions. Moreover, these methods enable the accurate reconstruction of plant acute wounding responses at single-cell resolution. Collectively, these advancements expand the applicability of plant single-cell genomics across a wider range of species and tissues, paving the way for comprehensive Plant Cell Atlases for plant species.

    PMID:41310055 | DOI:10.1038/s41592-025-02900-2

  • Gene Expression Differentiation Is Consistent with Local Adaptation across an Elevational Gradient in Drummond’s Rockcress (Boechera stricta) 

    Shelby L Tisinai

    J Hered. 2025 Oct 15:esaf081. doi: 10.1093/jhered/esaf081. Online ahead of print.

    ABSTRACT

    A central goal of evolutionary biology is to understand the mechanisms conferring adaptation. Gene expression is sensitive to environmental variability; thus, investigating gene expression differentiation among populations may reveal signatures of selection from predictable environmental conditions. Environmental pressures that covary with elevation gain (e.g., temperature) result in stark environmental differences along short distances. The phenological and life history traits of plants inhabiting elevational gradients might track these variables, providing an opportunity for testing hypotheses. Boechera stricta occupies a steep elevation gradient in the Rocky Mountains. Here, we grew F3 seeds from at least two genotypes each from five populations of B. stricta in a greenhouse. Analysis of leaf RNAseq data permitted tests of these hypotheses: 1) populations exhibit significant among population genetic variation in gene expression; 2) differentiation in gene expression (QST) exceeds neutral expectations (FST); and 3) the putative functions of differentially expressed genes are predicable based on a priori knowledge of environmental pressures that vary with elevation. Differentiation in gene expression (average QST = 0.53) significantly exceeded neutral differentiation (average FST = 0.17), implicating selection as a potential cause of genetically divergent patterns of gene expression. The putative functions of differentially expressed genes covarying with elevation were enriched for biological processes related to conditions that vary with elevation (circadian rhythm, response to light, chloroplast organization, and vegetative to reproductive meristem transitions). This study reveals considerable differentiation in gene expression, which may provide a mechanism for rapid adaptation to local environmental conditions in this and other species.

    PMID:41092278 | DOI:10.1093/jhered/esaf081

  • Genetic and environmental influences on the distributions of three chromosomal drive haplotypes in maize 

    Meghan J Brady

    bioRxiv [Preprint]. 2025 May 27:2025.05.22.655462. doi: 10.1101/2025.05.22.655462.

    ABSTRACT

    Meiotic drive elements are regions of the genome that are transmitted to progeny at frequencies that exceed Mendelian expectations, often to the detriment of the organism. In maize there are three prevalent chromosomal drive elements known as Abnormal chromosome 10 (Ab10), K10L2, and the B chromosome. There has been much speculation about how these drivers might interact with each other and the environment in traditional maize landraces and their teosinte ancestors. Here we used genotype-by-sequencing data to score more than 10,000 maize and teosinte lines for the presence or absence of each driver. Less than ~0.5% of modern inbred lines carry chromosomal drivers. Among individuals from 5331 open-pollinated landraces, 6.32% carried Ab10, 5.16% carried K10L2, and 12.28% carried at least one B chromosome. Using a GWAS approach we identified unlinked loci that associate with the presence or absence of the selfish genetic elements. Many genetic modifiers are positively associated with the drivers, suggesting that there may have been selection for alleles that ameliorate their negative fitness consequences. We then assessed the contributions of population structure, associated loci, and the environment on the distribution of each chromosomal driver. There was no significant relationship between any chromosomal driver and altitude, contrary to conclusions based on smaller studies. Our data suggest that the distribution of the major chromosomal drivers is primarily influenced by neutral processes and the deleterious fitness consequences of the drivers themselves. While each driver has a unique relationship to genetic background and the environment, they are largely unconstrained by either.

    PMID:40501570 | PMC:PMC12154789 | DOI:10.1101/2025.05.22.655462

2018 Cohort

  • 1H-NMR Guided Isolation of Bioactive Compounds from Species of the Genus Piper 

    Author: Ian S Wallace 

    Molecules. 2025 Apr 30;30(9):2020. doi: 10.3390/molecules30092020.

    ABSTRACT

    The discovery of bioactive natural products is often challenged by the complexity of isolating and characterizing active compounds within diverse mixtures. Previously, we introduced a 1H NMR-based weighted gene correlation network analysis (WGCNA) approach to identify spectral features linked to growth inhibitory activity of Piper (Piperaceae) leaf extracts against model plant, fungal, and bacterial organisms. This method enabled us to prioritize specific spectral features linked to bioactivity, offering a targeted approach to natural product discovery. In this study, we validate the predictive capacity of the WGCNA by isolating the compounds responsible for the bioactivity-associated resonances and confirming their antifungal efficacy. Using growth inhibition assays, we verified that the isolated compounds, including three novel antifungal agents, exhibited significant bioactivity. Notably, one of these compounds contains a rare imidazolium heterocyclic motif, marking a new structural class in Piper. These findings substantiate the 1H NMR-based WGCNA as a reliable tool for identifying structural types associated with biological activity, streamlining the process of discovering bioactive natural products in complex extracts.

    PMID:40363825 | PMC:PMC12073215 | DOI:10.3390/molecules30092020

  • 2023 Retreat Agenda

  • 2025 Spring Symposium Save the Date

  • 35th E. S. Luttrell Lecture

  • A Case Study for Visual Detection of a Systemic Disease: Optimizing Identification of Phony Peach Disease Based on Statistical and Machine Learning Models 

    Weiqi Luo

    Phytopathology. 2025 Jun 22. doi: 10.1094/PHYTO-03-25-0093-R. Online ahead of print.

    ABSTRACT

    Phony peach disease (PPD), caused by Xylella fastidiosa subsp. multiplex (Xfm), poses a significant threat to commercial peach orchards in Georgia. Early and accurate detection is essential for effective disease management, yet visual assessment remains the primary approach for diagnosing PPD symptoms due to the high cost and logistical challenges of qPCR-based detection of Xfm. We evaluated the accuracy of visual PPD assessment and examined the factors influencing rater performance, symptom reliability, and optimal survey deployment strategies with CART/Random Forest analyses and simulations. Internode length was the most reliable symptom for PPD identification in two peach cultivars, consistently outperforming other physical traits such as canopy flatness and shape. Primer pair C06Xf-bamA had the greatest relative sensitivity, making it the preferred choice for qPCR confirmation. Principal component analysis suggested that rater experience significantly improved agreement with qPCR results and repeated assessments of the same orchards further enhanced consistency for raters. Simulations results suggested that deploying two experienced raters may provide the highest detection diagnostic accuracy for survey purposes, particularly when qPCR-based pathogen detection is unavailable. Last, PPD-affected trees, through PCR verification and visual identification, exhibited higher mortality rates than Xfm-negative trees, reinforcing the need for early detection and removal to limit disease spread. These findings underscore the importance of strategic rater deployment, targeted symptom selection, and integrating molecular diagnostics when feasible.

    PMID:40544457 | DOI:10.1094/PHYTO-03-25-0093-R

  • A cell-type-specific regulon controlling monoterpene indole alkaloid biosynthesis with feedback and feedforward activation loops 

    Chenxin Li

    New Phytol. 2025 Nov 9. doi: 10.1111/nph.70712. Online ahead of print.

    ABSTRACT

    Monoterpene indole alkaloids (MIA) are a diverse class of plant natural products produced by a subset of lineages within the Asterid clade of eudicots. The diversity of MIAs provides a unique opportunity to study not only the evolution of biosynthetic genes but also their regulation. In this study, we investigate the cell type specificity of biosynthetic genes and coexpressed transcription factors (TFs) in two MIA-producing Asterid species, Catharanthus roseus, a well-studied MIA-producing species, and Camptotheca acuminata, which belongs to an early-diverging lineage of the Asterid clade. We generated single-cell RNA-seq data from the C. acuminata stem, the primary site of camptothecin biosynthesis. We found that MIA biosynthetic genes in C. acuminata are specific to exceptionally rare cell populations. We discovered MYB and bHLH TFs coexpressed in the same cell types as MIA biosynthetic genes in the C. acuminata stem. Interestingly, the C. roseus orthologs of these TFs are idioblast-specific and activate MIA biosynthetic genes in C. roseus upon overexpression. We constructed an extended gene regulatory network for the idioblast metabolic regulon in C. roseus, which contains both feedback and feedforward activation loops. This study demonstrates co-option of the same clades of TFs for regulation of cell-type-specific MIA biosynthesis across two Asterid species separated by c. 115 million years of evolution. Investigating cell-type-specific TFs that are coexpressed with biosynthetic genes across multiple species is a powerful strategy to increase the power for the discovery of plant metabolic regulators.

    PMID:41208325 | DOI:10.1111/nph.70712

  • A compendium of nonredundant short polymerase III promoters for CRISPR applications 

    Michihito Deguchi

    Plant Physiol. 2025 Jul 3;198(3):kiaf294. doi: 10.1093/plphys/kiaf294.

    ABSTRACT

    Minimal native and synthetic Polymerase III promoters enable efficient and customizable CRISPR multiplexing in plants, expanding genome engineering capabilities

    PMID:40673482 | PMC:PMC12268498 | DOI:10.1093/plphys/kiaf294

  • A global dataset of terrestrial biological nitrogen fixation 

    Carla R Reis Ely

    Sci Data. 2025 Aug 5;12(1):1362. doi: 10.1038/s41597-025-05131-4.

    ABSTRACT

    Biological nitrogen fixation (BNF) is the main natural source of new nitrogen inputs in terrestrial ecosystems, supporting terrestrial productivity, carbon uptake, and other Earth system processes. We assembled a comprehensive global dataset of field measurements of BNF in all major N-fixing niches across natural terrestrial biomes derived from the analysis of 376 BNF studies. The dataset comprises 32 variables, including site location, biome type, N-fixing niche, sampling year, quantification method, BNF rate (kg N ha-1 y-1), the percentage of nitrogen derived from the atmosphere (%Ndfa), N fixer or N-fixing substrate abundance, BNF rate per unit of N fixer abundance, and species identity. Overall, the dataset combines 1,207 BNF rates for trees, shrubs, herbs, soil, leaf litter, woody litter, dead wood, mosses, lichens, and biocrusts, 152 herb %Ndfa values, 1,005 measurements of N fixer or N-fixing substrate abundance, and 762 BNF rates per unit of N fixer abundance for a total of 424 species across 66 countries. This dataset facilitates synthesis, meta-analysis, upscaling, and model benchmarking of BNF fluxes at multiple spatial scales.

    PMID:40764484 | DOI:10.1038/s41597-025-05131-4

  • A high-quality genome assembly of the tetraploid Teucrium chamaedrys unveils a recent whole genome duplication and a large biosynthetic gene cluster for diterpenoid metabolism 

    Abigail E Bryson

    Plant Commun. 2025 Jun 3:101393. doi: 10.1016/j.xplc.2025.101393. Online ahead of print.

    ABSTRACT

    Teucrium chamaedrys, also called wall germander, is a small woody shrub native to the Mediterranean region. Its name is derived from the Greek words meaning ‘ground oak’, since its tiny leaves resemble those of an oak tree. Teucrium species are proliferative producers of diterpenes, which afford them valuable properties widely co-opted in traditional and western medicines. Sequence and assembly of the 3 Gbp tetraploid T. chamaedrys revealed 74 diterpene synthase genes, with the vast representation of these diterpene synthases clustered along four genomic loci. Comparative genomics revealed that this cluster is mirrored in the closely related species, Teucrium marum. Along with the presence of several cytochrome p450 sequences, this region is the one of largest biosynthetic gene clusters identified. Teucrium is well known for accumulating clerodane-type diterpenoids which are produced from a kolavanyl diphosphate precursor. To elucidate the complex biosynthetic pathways of these medicinal compounds, we identified and functionally characterized several kolavanyl diphosphate synthases from T. chamaedrys. Its remarkable chemistry and tetraploidy make T. chamaedrys an interesting and unique model for studying genomic evolution and adaptation in plants.

    PMID:40468595 | DOI:10.1016/j.xplc.2025.101393

  • A nitric oxide reductase is a key enzyme target for eliminating fungal emissions of nitrous oxide 

    Blake A Oakley

    Fungal Genet Biol. 2025 Sep 23:104038. doi: 10.1016/j.fgb.2025.104038. Online ahead of print.

    ABSTRACT

    Nitrous oxide (N2O) derived from agricultural activity is a major contributor to Earth’s greenhouse effect. Synthetic nitrogen fertilizer applied at high levels, particularly combined with heavy rainfall events, generates hot spots of N2O emissions in agricultural fields due to the process of microbial denitrification. Here, a key conserved fungal denitrification enzyme necessary for N2O emissions was identified. Phylogenetic analysis revealed that fungal NOR1-like genes, with rare exceptions, are highly conserved and confined to the phylum Ascomycota. Plant pathogenic Fusarium species that possess NOR1 exhibited drastic differences in N2O production based on denitrification potential. Functional characterization of the p450nor nitric oxide reductase encoding gene, NOR1, in the soil-borne denitrifying maize pathogen, Fusarium verticillioides, showed that this enzyme is critical for fungal N2O production. Deletion of the single copy NOR1 gene in F. verticillioides eliminated N2O emissions. Complementation of deletion mutants via the NOR1 gene add-back restored wild type N2O emission levels and segregation analysis further corroborated the pivotal role of NOR1 for N2O emissions. We suggest targeting of the NOR1 enzyme as an effective strategy to reduce fungal-based N2O emissions.

    PMID:40998212 | DOI:10.1016/j.fgb.2025.104038

  • Aerial root formation in Oaxacan maize (Zea mays) landraces persists into the adult phase and is minimally affected by soil nitrogen and ambient humidity 

    Rafael E Venado

    Front Plant Sci. 2025 Jul 11;16:1607733. doi: 10.3389/fpls.2025.1607733. eCollection 2025.

    ABSTRACT

    Maize (Zea mays L.) is the most widely produced crop in the world, and conventional production requires significant amounts of synthetic nitrogen fertilizer, which has negative economic and environmental consequences. Maize landraces from Oaxaca, Mexico, can acquire nitrogen from nitrogen-fixing bacteria that live in a mucilage secreted by aerial nodal roots. The development of these nodal roots is a characteristic traditionally associated with the juvenile vegetative stage of maize plants. However, mature Oaxacan landraces develop many more nodes with aerial roots than commercial maize varieties. Our study shows that Oaxacan landraces develop aerial roots during the juvenile and adult vegetative phases and even during early flowering under greenhouse and field conditions. Surprisingly, the development of these roots was only minimally affected by soil nitrogen and ambient humidity. These findings are an essential first step in developing maize varieties to reduce fertilizer needs in maize production across different environmental conditions.

    PMID:40718026 | PMC:PMC12289584 | DOI:10.3389/fpls.2025.1607733

  • An updated sulfate transporter phylogeny uncovers a perennial-specific subgroup associated with lignification 

    Samantha M Surber

    Tree Physiol. 2025 Jul 11:tpaf080. doi: 10.1093/treephys/tpaf080. Online ahead of print.

    ABSTRACT

    Sulfate-proton co-transporters (SULTRs) mediate sulfate uptake, transport, storage, and assimilation in plants. The SULTR family has historically been classified into four groups (SULTR1-SULTR4), with well-characterized roles for SULTR groups 1, 2, and 4. However, the functions of the large and diverse SULTR3 group remain poorly understood. Here, we present an updated phylogenetic analysis of SULTRs across angiosperms, including multiple early-divergent lineages. Our results suggest that the enigmatic SULTR3 group comprises four distinct subfamilies that predate the emergence of angiosperms, providing a basis for reclassifying the SULTR family into seven subfamilies. This expanded classification is supported by subfamily-specific gene structures and amino acid substitutions in the substrate-binding pocket. Structural modeling identified three serine residues uniquely lining the substrate-binding pocket of SULTR3.4, enabling three hydrogen bonds with the phosphate ion. The data support the proposed neofunctionalization of this subfamily for phosphate allocation within vascular tissues. Transcriptome analysis of Populus tremula × alba revealed divergent tissue expression preferences among SULTR subfamilies and between genome duplicates. We observed partitioned expression in vascular tissues among the four SULTR3 subfamilies, with PtaSULTR3.4a and PtaSULTR3.2a preferentially expressed in primary and secondary xylem, respectively. Gene coexpression analysis revealed coordinated expression of PtaSULTR3.4a with genes involved in phosphate starvation responses and nutrient transport, consistent with a potential role in phosphate homeostasis. In contrast, PtaSULTR3.2a was strongly coexpressed with lignification and one-carbon metabolism genes and their upstream transcription regulators. PtaSULTR3.2a belongs to a eudicot-specific branch of the SULTR3.1 subfamily found only in perennial species, suggesting a specialized role in lignifying tissues. Together, our findings provide a refined phylogenetic framework for the SULTR family and suggest that the expanded SULTR3 subfamilies have undergone neofunctionalization during the evolution of vascular and perennial plants.

    PMID:40643194 | DOI:10.1093/treephys/tpaf080

  • Anionic lipids direct efficient microfluidic encapsulation of stable and functionally active proteins in lipid nanoparticles 

    Suresh Ambati

    Commun Mater. 2025;6(1):34. doi: 10.1038/s43246-025-00749-8. Epub 2025 Feb 22.

    ABSTRACT

    Because proteins do not efficiently pass through the plasma membrane, protein therapeutics are limited to target ligands located at the cell surface or in serum. Lipid nanoparticles can facilitate delivery of polar molecules across a membrane. We hypothesized that because most proteins are amphoteric ionizable polycations, proteins would associate with anionic lipids, enabling microfluidic chip assembly of stable EP-LNPs (Encapsulated Proteins in Lipid NanoParticles). Here, by employing anionic lipids we were able to efficiently load proteins into EP-LNPs at protein:lipid w:w ratios of 1:20. Several proteins with diverse molecular weights and isoelectric points were encapsulated at efficiencies of 70 75%-90% and remained packaged for several months. Proteins packaged in EP-LNPs efficiently entered mammalian cells and fungal cells with cell walls. The proteins delivered intracellularly were functional. EP-LNPs technology should improve cellular delivery of medicinal antibodies, enzymes, peptide antimetabolites, and dominant negative proteins, opening new fields of protein therapeutics.

    PMID:41146908 | PMC:PMC12553553 | DOI:10.1038/s43246-025-00749-8

  • Anne Frances Jarrell wins 1st Place at the NAPB 2023 Poster Competition!

    Anne Frances Jarrell from the 2021 Cohort won first place for the PhD Poster Competition at the 2023 National Association of Plant Breeders meeting!

    In Spring 2022, Anne Frances officially joined the Robin Buell lab as a Graduate Research Assistant. She is interested in using advances in genomics to improve crop breeding, specifically to increase sustainability and crop resiliency in the face of global climate change. Currently, this leads her to work with potatoes and their wild relatives.

    Learn more about Anne Frances and her work by visiting the Buell Lab website!

    Congratulations Anne Frances!

  • Assessing UV-C radiation treatments for dollar spot suppression in seashore paspalum 

    Willis Turner Spratling

    Plant Dis. 2025 Dec 8. doi: 10.1094/PDIS-08-24-1610-RE. Online ahead of print.

    ABSTRACT

    Dollar spot, caused by Clarireedia spp., is one of the most detrimental diseases of turfgrass worldwide, and control strategies usually involve frequent fungicide applications. These treatments are expensive, require special equipment and can contribute to fungicide resistance issues, underscoring the need for alternative management strategies. UV-C radiation has proven effective as a disease management tool in various cropping systems but is still largely unexplored in turfgrass. This study aimed to test the effects of UV-C radiation against dollar spot in seashore paspalum and to evaluate its impact on plant health and performance. In assessing UV-C’s efficacy directly against C. monteithiana, daily radiation treatments ranging from 27.5 J m-2 to 77.0 J m-2 were shown to effectively reduce mycelial growth. Additionally, in vitro UV-C treatment administered in darkness was observed to be more effective in reducing pathogen growth than treatment administered in lighted conditions. In a growth chamber setting, daily 66.0 J m-2 UV-C treatment significantly reduced dollar spot severity in seashore paspalum without causing phytotoxic damage to plant tissues. In field trials, a novel UV-C application system was implemented by modifying a robotic mower to autonomously deliver UV-C radiation to seashore paspalum plots. UV-C treatment in the field significantly reduced dollar spot severity. Moreover, UV-C treatment led to several physiological and performance enhancements, including increased chlorophyll content, shoot density, surface firmness, and green speed. Findings from this study indicate that UV-C radiation may be used as an effective physical control to complement existing dollar spot management practices.

    PMID:41362131 | DOI:10.1094/PDIS-08-24-1610-RE

  • Biology, Ecology, and Management of Prevalent Thrips Species (Thysanoptera: Thripidae) Impacting Blueberry Production in the Southeastern United States 

    Rosan Adhikari

    Insects. 2025 Jun 24;16(7):653. doi: 10.3390/insects16070653.

    ABSTRACT

    Blueberry is a high-value fruit crop in the United States, with Georgia and Florida serving as important early-season production regions. In these areas, several thrips species (Thysanoptera: Thripidae), including Frankliniella tritici (Fitch), Frankliniella bispinosa (Morgan), and Scirtothrips dorsalis (Hood), have emerged as economically significant pests. While F. tritici and F. bispinosa primarily damage floral tissues, S. dorsalis targets young foliage. Their rapid reproduction, high mobility, and broad host range contribute to rapid population buildup and complicate the management programs. Species identification is often difficult due to overlapping morphological features and requires the use of molecular diagnostic tools for accurate identification. Although action thresholds, such as 2-6 F. tritici per flower cluster, are used to guide management decisions, robust economic thresholds based on yield loss remain undeveloped. Integrated pest management (IPM) practices include regular monitoring, cultural control (e.g., pruning, reflective mulch), biological control using Orius insidiosus (Say) and predatory mites, and chemical control. Reduced-risk insecticides like spinetoram and spinosad offer effective suppression while minimizing harm to pollinators and beneficial insects. However, the brief flowering period limits the establishment of biological control agents. Developing species-specific economic thresholds and phenology-based IPM strategies is critical for effective and sustainable thrips management in blueberry cropping systems.

    PMID:40725285 | DOI:10.3390/insects16070653

  • Bordetellae colonization oligosaccharide (b-Cool), a glycan crucial for nasal colonization 

    Yang Su

    Sci Adv. 2025 Sep 5;11(36):eadw7764. doi: 10.1126/sciadv.adw7764. Epub 2025 Sep 3.

    ABSTRACT

    Respiratory tract infections pose considerable global health challenges. Upper airway colonization is pivotal to these infections, including those caused by Bordetella species. We identified an oligosaccharide, bordetellae colonization oligosaccharide (b-Cool), crucial for early nasal colonization of Bordetella bronchiseptica. We characterized the structure of b-Cool by LC-MS and NMR and found that it is prevalent across a diverse range of bordetellae, including Bordetella pertussis, which causes whooping cough in humans. A B. bronchiseptica mutant lacking b-Cool (Δb-Cool) showed significantly delayed and decreased colonization in mouse nasopharynx and nasal epithelia, resulting in decreased transmission. The colonization defect of Δb-Cool was rescued in mucin deficient mice, suggesting that b-Cool may facilitate colonization in the presence of airway mucins.

    PMID:40901963 | DOI:10.1126/sciadv.adw7764

  • Building an expanded bio-based economy through synthetic biology 

    Andrea M Garza Elizondo

    Biotechnol Adv. 2025 Dec 6:108775. doi: 10.1016/j.biotechadv.2025.108775. Online ahead of print.

    ABSTRACT

    The field of synthetic biology is essential to the continued development of a bio-based economy, creating mechanisms to supply carbon needed in the economy by both converting existing end-of-life wastes as well as by creating novel, purpose-grown and sustainable feedstocks. Here, we first discuss the near- and long-term resources available for use as feedstocks for bioconversion as well as the output molecules needed for building the foundation of an expanded bio-based economy. We then outline the organisms and phenotypic traits that are needed for the performance-advantaged chassis organisms of the future. Furthermore, we detail the advances, challenges, and opportunities in both microbial and plant synthetic biology relevant to expanding the bio-based economy. Finally, we explore technologies that have and will further enable advances in synthetic biology and the greater bio-based economy.

    PMID:41360191 | DOI:10.1016/j.biotechadv.2025.108775

  • Building genomic resources to facilitate the study and use of Solanum microdontum, a wild relative of cultivated potato 

    Anne Frances Jarrell

    G3 (Bethesda). 2025 Oct 23:jkaf253. doi: 10.1093/g3journal/jkaf253. Online ahead of print.

    ABSTRACT

    Solanum microdontum Bitter is a diploid wild Andean relative of potato that has shaped the domestication and adaptation of modern cultivated potato to diverse environments. Solanum microdontum has the potential to provide a wealth of untapped genetic material for use in addressing current challenges in potato breeding. Here, we report a high-quality 772 Mb reference genome sequence for S. microdontum that is anchored to 12 chromosomes. The resulting genome assembly has 99.0% complete Benchmarking Universal Single Copy Orthologs and an N50 scaffold length of over 57 Mb, indicating a high level of completeness. Annotation of the assembly resulted in the identification of 37,324 protein coding genes and 65% repetitive sequence. A total of 1,187 nucleotide-binding leucine-rich repeat genes were predicted from the assembly, of which 93.1% overlapped an annotated high-confidence gene model. A k-mer based kinship matrix derived from a 107-member S. microdontum diversity panel revealed an underlying population structure that corresponds to geographic proximity. The S. microdontum dataset enhances publicly available potato genome resources by providing breeders with genetic, molecular, and germplasm resources for newly developed diploid potato breeding programs.

    PMID:41128648 | DOI:10.1093/g3journal/jkaf253

  • Candidate genes at the Rmi1 locus for resistance to Meloidogyne incognita in soybean 

    Kelly Goode

    Theor Appl Genet. 2025 Oct 29;138(11):286. doi: 10.1007/s00122-025-05065-w.

    ABSTRACT

    The RKN resistance locus Rmi1 was fine-mapped to two genes on chromosome 10, a glycosyl hydrolase family 9 β-1,4-endoglucanase gene and a type I pectin methylesterase gene. Root-knot nematodes (Meloidogyne spp.) are a serious threat to soybean production in the southeast USA, with yield losses of more than $165 million in 2023. Development and deployment of resistant soybean cultivars is the most effective strategy for managing these nematode pests; however, the identity of the resistance genes and underlying mechanism of resistance remains obscure. An additive resistance gene, Resistance to M. incognita-1 (Rmi1), to the predominant species, was first identified in soybean cultivar Forrest but never mapped to a genomic region. Multiple mapping studies have identified a major quantitative trait locus (QTL) with additive action on chromosome 10. In this study, a population consisting of 170 F2:3 families derived from a cross of Bossier (susceptible) × Forrest (resistant) was initially used to confirm that Rmi1 is in the chromosome 10 QTL. Subsequently, 884 F5:6 recombinant inbred lines (RILs) derived from the same cross were used to fine-map the Rmi1 causal gene(s) to two genes – a β-1,4-endoglucanase (Glyma.10G017000, EG) and a pectin methylesterase/methylesterase inhibitor (Glyma.10G017100, PME1). Both gene candidates have the potential to play a role in the resistance response to M. incognita. Both gene promoters harbor SNPs and indels and the encoded proteins exhibit amino acid polymorphisms, including a premature stop in PME1 of resistant soybeans. Additionally, both genes show a higher expression level in susceptible roots compared to resistant roots in the absence of infection. This suggests that Rmi1 may confer one or more pre-existing differences related to cell wall modification in soybean roots, ultimately leading to a decrease in susceptibility.

    PMID:41160124 | DOI:10.1007/s00122-025-05065-w

  • Celebrating the fifth edition of the International Symposium on Fungal Stress – ISFUS, a decade after its 2014 debut 

    Alene Alder-Rangel

    Fungal Biol. 2025 Aug;129(5):101590. doi: 10.1016/j.funbio.2025.101590. Epub 2025 May 6.

    ABSTRACT

    The Fifth International Symposium on Fungal Stress (ISFUS) brought together in Brazil many of the leaders in the field of fungal stress responses, from fourteen countries, for four days of outstanding science ranging from basic research to studies with agricultural, medical, industrial, and environmental significance. In addition to the excellent oral and poster presentations, the Symposium organisers ensured that all participants had ample opportunity to engage, socialise, and network to exchange ideas and share research. The conference was enhanced by the world-class venue near Iguazu Falls, probably the greatest natural phenomenon in South America.

    PMID:40707112 | DOI:10.1016/j.funbio.2025.101590

  • Characterization of Pseudomonas alliivorans strains isolated from Georgia, USA: insights into genomic diversity and pathogenicity in onions 

    Mei Zhao

    Appl Environ Microbiol. 2025 Nov 25:e0164325. doi: 10.1128/aem.01643-25. Online ahead of print.

    ABSTRACT

    Pseudomonas alliivorans is an important emerging pathogen affecting numerous crops. The species is closely related to Pseudomonas viridiflava, with which P. alliivorans strains were often misidentified in the past. Here, we investigated the genetic and pathogenic characteristics of P. alliivorans strains isolated primarily from onions and weeds in Georgia, USA, using whole-genome sequencing, comparative genomics, and functional assays. We delineated the core genome and genetic diversity of these isolates, assessed their pathogenicity on onion foliage and red onion scales, and examined the roles of key virulence determinants (Hrp1-type III secretion system [T3SS], rhizobium-T3SS, type II secretion systems [T2SSs], and thiosulfinate [allicin]-tolerance alt cluster). Our results showed that the Hrp1-T3SS is pivotal for pathogenicity in P. alliivorans, whereas the rhizobium-T3SS, T2SSs, and alt cluster do not contribute to symptom development on red onion scales. Notably, the alt cluster confers in vitro thiosulfinate tolerance, supporting bacterial survival against onion-derived antimicrobial compounds. Additionally, homologous recombination in P. alliivorans occurs infrequently (at approximately one-tenth the rate of point mutations) and involves divergent DNA segments. The alt cluster is acquired through horizontal gene transfer, as evidenced by its lower GC content and the presence of adjacent transposases. In summary, our research provides valuable insights into the genetic diversity, evolutionary dynamics, and virulence mechanisms of P. alliivorans strains from Georgia, USA.IMPORTANCEPseudomonas alliivorans is an emerging plant pathogen that threatens onion and other plants of economic importance. This study identifies key traits that help this bacterium cause disease, such as a specific secretion system critical for infecting onions, and a gene cluster that aids bacterial survival in onion tissues. Beyond highlighting weed as a potential inoculum source and supporting better weed management, the findings of this research open avenues for more targeted disease menegement. By unraveling the genetics of this pathogen, we can develop improved ways to detect, prevent, and reduce its impact, protecting crop health and yields.

    PMID:41288358 | DOI:10.1128/aem.01643-25

  • Comparative Analyses of Four Reference Genomes Reveal Exceptional Diversity and Weak Linked Selection in the Yellow Monkeyflower (Mimulus guttatus) Complex 

    John T Lovell

    Mol Ecol Resour. 2025 Jul 22:e70012. doi: 10.1111/1755-0998.70012. Online ahead of print.

    ABSTRACT

    Yellow monkeyflowers (Mimulus guttatus complex, Phrymaceae) are a powerful system for studying ecological adaptation, reproductive variation, and genome evolution. To initiate pan-genomics in this group, we present four chromosome-scale assemblies and annotations of accessions spanning a broad evolutionary spectrum: two from a single M. guttatus population, one from the closely related selfing species M. nasutus, and one from a more divergent species M. tilingii. All assemblies are highly complete and resolve centromeric and repetitive regions. Comparative analyses reveal such extensive structural variation in repeat-rich, gene-poor regions that large portions of the genome are unalignable across accessions. As a result, this Mimulus pan-genome is primarily informative in genic regions, underscoring limitations of resequencing approaches in such polymorphic taxa. We document gene presence-absence, investigate the recombination landscape using high-resolution linkage data, and quantify nucleotide diversity. Surprisingly, pairwise differences at fourfold synonymous sites are exceptionally high-even in regions of very low recombination-reaching ~3.2% within a single M. guttatus population, ~7% within the interfertile M. guttatus species complex (approximately equal to SNP divergence between great apes and Old World monkeys), and ~7.4% between that complex and the reproductively isolated M. tilingii. Genome-wide patterns of nucleotide variation show little evidence of linked selection, and instead suggest that the concentration of genes (and likely selected sites) in high-recombination regions may buffer diversity loss. These assemblies, annotations, and comparative analyses provide a robust genomic foundation for Mimulus research and offer new insights into the interplay of recombination, structural variation, and molecular evolution in highly diverse plant genomes.

    PMID:40693537 | DOI:10.1111/1755-0998.70012

  • Comparative Transcriptomic Analysis of Soybean Recombinant Inbred Lines Differing at the Rmi1 Locus for Resistance to Meloidogyne incognita During Early Stages of Nematode Infection 

    Kelly Goode

    Phytopathology. 2025 Jun 11. doi: 10.1094/PHYTO-04-25-0143-SC. Online ahead of print.

    ABSTRACT

    Root-knot nematodes (Meloidogyne spp.) are a continuing threat to soybean production, with M. incognita being the predominant species. The deployment of Mi-resistant soybean cultivars is a primary management strategy, but the underlying molecular mechanisms contributing to resistance remain unknown. A single, additive gene for resistance to M. incognita, Rmi1, was previously identified in soybean cv. Forrest and associated with the emigration of second-stage juveniles from the roots. To better understand the Rmi1-mediated resistance response, we used Forrest-derived F5 RILs differing for Rmi1 to analyze global changes in gene expression in response to M. incognita infection at 2- and 4-days post inoculation. We identified 1,471 differentially expressed (DE) genes in the compatible interaction and 1,037 DE genes in the incompatible interaction. Forty-five percent of DE genes were DE in both interactions, 42% (856) were unique to the compatible interaction, and 13% (261) were unique to the incompatible interaction. Genes uniquely DE in the incompatible interaction included genes involved in cell wall modification, hormone signaling, endomembrane trafficking, and redox reactions providing new insights into the resistance mechanism mediated by Rmi1 in soybean to root-knot nematodes.

    PMID:40498525 | DOI:10.1094/PHYTO-04-25-0143-SC

  • Conflicting kinesin-14s in a single chromosomal drive haplotype 

    Author: Kelly Dawe

    Genetics. 2025 May 14:iyaf091. doi: 10.1093/genetics/iyaf091. Online ahead of print.

    ABSTRACT

    In maize, there are two meiotic drive systems that target large heterochromatic knobs composed of tandem repeats known as knob180 and TR-1. The first meiotic drive haplotype, Abnormal chromosome 10 (Ab10) confers strong meiotic drive (∼75% transmission as a heterozygote) and encodes two kinesins: KINDR, which associates with knob180 repeats and TRKIN, which associates with TR-1 repeats. Prior data show that meiotic drive is conferred primarily by the KINDR/knob180 system while the TRKIN/TR-1 system seems to have little or no role, making it unclear why Trkin has been maintained in Ab10 haplotypes. The second meiotic drive haplotype, K10L2, confers a low level of meiotic drive (∼51-52%) and only encodes the TRKIN/TR-1 system. Here we used long-read sequencing to assemble the K10L2 haplotype and showed that it has strong homology to an internal portion of the Ab10 haplotype. We also carried out CRISPR mutagenesis to test the role of Trkin on Ab10 and K10L2. The data indicate that the Trkin gene on Ab10 does not improve drive or fitness but instead has a weak deleterious effect when paired with a normal chromosome 10. The deleterious effect is more severe when Ab10 is paired with K10L2: in this context functional Trkin on either chromosome nearly abolishes Ab10 drive. Mathematical modeling based on the empirical data suggest that Trkin is unlikely to persist on Ab10. We conclude that Trkin either confers an advantage to Ab10 in untested circumstances or that it is in the process of being purged from the Ab10 population.

    PMID:40365704 | DOI:10.1093/genetics/iyaf091

  • Correction: Drought adaptation index (DAI) based on BLUP as a selection approach for drought-resilient switchgrass germplasm 

    Shiva Om Makaju

    Front Genet. 2025 Nov 12;16:1731825. doi: 10.3389/fgene.2025.1731825. eCollection 2025.

    ABSTRACT

    [This corrects the article DOI: 10.3389/fgene.2025.1626083.].

    PMID:41311856 | PMC:PMC12648043 | DOI:10.3389/fgene.2025.1731825

  • Cross-resistance in Alternaria brassicicola from naturally infested broccoli seeds against two succinate dehydrogenase inhibitor fungicides 

    Navjot Kaur

    Appl Environ Microbiol. 2025 Sep 4:e0108325. doi: 10.1128/aem.01083-25. Online ahead of print.

    ABSTRACT

    Seeds can serve as a vehicle for the dissemination of pests and pathogens around the world. We recently demonstrated the association of pathogenic Alternaria brassicicola isolates with reduced sensitivity to azoxystrobin (quinone-outside inhibitor [QoI]) in naturally infested commercial broccoli seeds. In this study, we further demonstrate that these isolates were also resistant to two succinate dehydrogenase inhibitor (SDHI) fungicides. Sensitivity of representative A. brassicicola isolates (n = 58) from naturally infested broccoli seedlots to QoI and SDHI fungicides was evaluated under in vitro conditions. Interestingly, 15% (n = 9/58) of the A. brassicicola isolates with reduced sensitivity to azoxystrobin also displayed reduced sensitivity to two commonly used SDHI fungicides (boscalid and penthiopyrad) in broccoli, indicating a potential case of cross-resistance to SDHI fungicides. Ninety-three percent of the isolates (n = 54/58) were resistant to both boscalid and penthiopyrad, while 100% isolates displayed sensitivity to fluopyram. Sequence analysis of sdh genes revealed the presence of only one point mutation (H134R) in the sdhC gene in isolates that displayed resistance to boscalid and penthiopyrad. We also developed and validated allele-specific primers targeting the H134R mutation for rapid screening of SDHI resistance in A. brassicicola. We also found that boscalid-resistant isolates exhibited significantly reduced mycelial growth. However, spore germination rates among different resistant isolates were not different, suggesting that resistant isolates remain competitive in natural populations. Overall, this study provides the first evidence of fungicide resistance to SDHI fungicides in A. brassicicola isolated from naturally infested broccoli seeds and underscores the importance of seeds as a potential source for introducing fungicide resistance across geographical locations.

    IMPORTANCE: Alternaria brassicicola is a fungal seed-borne pathogen that can be disseminated via commercial seeds across transplant houses and commercial broccoli fields. Our study provides the first evidence that commercial broccoli seeds can harbor pathogenic A. brassicicola isolates with cross-resistance to two succinate dehydrogenase inhibitor (SDHI) fungicides. We observed that 93% of the A. brassicicola isolates from naturally infested commercial broccoli seeds contained a point mutation that conferred resistance to two SDHI fungicides (boscalid and penthiopyrad). Furthermore, we developed a PCR-based allele-specific assay for the rapid detection and monitoring of fungicide resistance. Our study highlights the importance of seed health testing and potential dissemination of fungicide-resistant isolates locally and globally, thus impacting disease management strategies.

    PMID:40905662 | DOI:10.1128/aem.01083-25

  • Deciphering the Biochemical Functions and Nucleotide Sugar Donor Specificity Determinants of Dicot GT61 Glycosyltransferases Involved in Xylan Substitutions 

    Ruiqin Zhong

    Plant Cell Physiol. 2025 Sep 26:pcaf122. doi: 10.1093/pcp/pcaf122. Online ahead of print.

    ABSTRACT

    Plant cell wall polysaccharide glycosyltransferases catalyze the transfer of sugars from specific nucleotide sugar donors onto specific acceptor substrates. The mechanisms of how their enzymatic specificity is determined is one of the long-standing questions in plant cell wall biology. In this report, we studied the biochemical functions of Arabidopsis and poplar GT61 glycosyltransferases involved in xylan substitutions and investigated the molecular determinants of their nucleotide sugar donor specificity. Enzymatic activity assays of recombinant proteins of Arabidopsis and poplar GT61 members demonstrated that two of them, AtX2AT1 and PtrX2AT1, exhibited xylan 2-O-arabinosyltransferase activities specifically using UDP-Araf, two other ones, AtXYXT2/3, possessed xylan 2-O-xylosyltransferase activities specifically using UDP-Xyl, and three other ones, PtrXXAT1/2/3, were able to catalyze the transfer of 2-O-Araf and 2-O-Xyl onto xylan using both UDP-Araf and UDP-Xyl. Structural modeling and molecular docking of PtrXXAT1 identified amino acid residues involved in interacting with UDP-Araf and UDP-Xyl at the putative active site and site-directed mutagenesis revealed their critical roles in PtrXXAT1 catalytic activities. Furthermore, structural alignment and reciprocal swapping of UDP-Xyl-interacting residues of PtrXXAT1 with their corresponding residues of AtX2AT1 pinpointed key residues determining their nucleotide sugar donor specificity. Our results indicate that Arabidopsis and poplar GT61 members catalyze 2-O-Araf- and/or 2-O-Xyl substitutions of xylan and that subtle structural differences in their substrate-binding pockets could alter their substrate specificity toward nucleotide sugar donors.

    PMID:41001967 | DOI:10.1093/pcp/pcaf122

  • Design of genus-specific semi-nested primers for simple and accurate identification of Enterobacter strains 

    Sara Jordan

    BMC Microbiol. 2025 Jul 28;25(1):456. doi: 10.1186/s12866-025-04175-1.

    ABSTRACT

    BACKGROUND: The genus Enterobacter, in the family Enterobacteriaceae, is of both clinical and environmental importance. This genus has undergone frequent taxonomic changes, making it challenging to identify taxa even at genus level. This study aimed to design Enterobacter genus-specific primers that can be used for simple PCR identification of large sets of putative Enterobacter isolates.

    RESULTS: Comparative genomic approaches were employed to identify genes that were universally present on Enterobacter genomes but absent from the genomes of other members of the family Enterobacteriaceae, based on an initial set of 89 genomes. The presence of these genes was further confirmed in 4,276 Enterobacter RefSeq genomes. While no strictly genus-specific genes were identified, the hpaB gene demonstrated a restricted distribution outside of the genus Enterobacter. Semi-nested primers were designed for hpaB and its flanking gene hpaC (hpaBC) and evaluated on 123 strains in single-tube PCR reactions. All taxa showing positive reactions belonged to the genus Enterobacter. For Enterobacter strains the PCR yielded two amplicons at 110 bp and at 370 bp, while strains only displaying the 110 bp amplicon were classified as Leclercia pneumoniae. A blind-test on 120 strains accessioned as Enterobacter sp. from the USDA-ARS culture collection (NRRL), revealed that one third of the strains had an incorrect genus assignment. Comparison of gene trees of the hpaBC fragment sequences with marker genes frequently used for single-gene barcoding or multi-locus sequence analysis (MLSA) further demonstrated its potential for preliminary species identification.

    CONCLUSIONS: The nested PCR assay represents a rapid and cost-effective approach for preliminary identification of Enterobacter species. As the primer design was based on large-scale genomic comparison, including currently undescribed species clades, it will remain valid even after taxonomic changes within the genus.

    PMID:40722002 | DOI:10.1186/s12866-025-04175-1

  • Detection of the gummy stem blight pathogens (Stagonosporopsis spp.) in watermelon using field-adapted LAMP assays and rapid DNA extraction protocols 

    Jorge Alberto Reyes Pineda

    Plant Dis. 2025 Aug 6. doi: 10.1094/PDIS-12-24-2589-SR. Online ahead of print.

    ABSTRACT

    Gummy stem blight (GSB), caused by three Stagonosporopsis species, S. citrulli, S. cucurbitacearum and S. caricae, is one of the most economically important diseases hindering watermelon production worldwide. Since there is no commercial resistance to GSB in watermelon cultivars, its management depends on cultural practices and preventative fungicides. Therefore, efficient methods for the detection of Stagonosporopsis species that could aid management decisions are required. To help achieve this, a loop-mediated isothermal amplification (LAMP) assay specific to S. citrulli (SCIT850) was developed under two detection formats: fluorescence quantification and endpoint colorimetric detection. The SCIT850 assay was determined to be specific to its target species and exhibited a consistent sensitivity of 1 pg of genomic DNA under both formats. The assay can be combined with a previously reported LAMP assay for the collective detection of the three Stagonosporopsis spp. (STAGY), which have comparable sensitivity to SCIT850 and can aid in species discrimination. A field diagnostic system for GSB-causing Stagonosporopsis was developed by coupling the SCIT850 and STAGY assays to quick DNA extraction protocols. Two DNA extraction methods were tested: one from leaves using cellulose dipsticks, and one from steel rods (typical of spore traps) using Chelex100. With the dipstick method, we detected pathogen DNA in inoculated asymptomatic, mildly infected, and severely infected plants, while with the Chelex100 we detected pathogen DNA from rods infested with as few as 500 spores. The SCIT850 and STAGY assays coupled with these quick sample processing methods could be adapted for field deployment, which would allow growers to make efficient and timely management decisions based on detection of the actual Stagonosporopsis species present in the field.

    PMID:40767855 | DOI:10.1094/PDIS-12-24-2589-SR

  • Determining the causal agents of Alternaria leaf blight and head rot affecting broccoli in the Eastern United States 

    Roy L Davis

    Plant Dis. 2025 May 22. doi: 10.1094/PDIS-01-25-0117-SR. Online ahead of print.

    ABSTRACT

    Alternaria brassicicola is the causal agent typically associated with Alternaria leaf blight and head rot (ABHR) disease in broccoli and related crops in the Eastern United States. Recently a new species, A. japonica, has been reported as causing disease in broccoli and other vegetables in this region. We conducted a multi-state pathogen survey during the growing seasons of 2022 and 2023 to assess the distribution and occurrence of A. japonica in relation to A. brassicicola in five broccoli-producing states. Our approach specifically targeted collection of broccoli leaves with lesions typical of ABHR within commercially grown fields managed using either organic or conventional approaches in Connecticut, Massachusetts, New York, Virginia, and Georgia. Only typical ABHR leaf lesions were selected for pathogen isolation and, subsequently, sequencing of the Alternaria major allergen a1 gene was used to identify Alternaria species. The predominant species isolated was A. brassicicola (88% in 2022 and 94% in 2023) and the second most common was A. alternata (12% in 2022 and 6% in 2023), which was obtained from fields in Connecticut and Massachusetts in 2022, and in Virginia in both years. Alternaria japonica was not found in either year. Symptoms of A. alternata were indistinguishable from A. brassicicola, as were colony morphologies. While A. alternata is considered a generalist and of little consequence for broccoli, it is considered a pathogen of significance on multiple crops (blueberry, citrus, pistachios), but there remains scant information on the disease etiology on broccoli. Therefore, we inoculated broccoli with A. alternata in controlled conditions in order to shed light on possible differences in infectivity of these species on broccoli. Results of our study showed that A. alternata is pathogenic on broccoli, capable of initiating infection and causing lesions typical of ABHR. This indicates that future disease surveys of ABHR should conclusively identify species of Alternaria that are causing disease. Additional research is needed to determine the significance of this finding in relation to yield impacts, epidemiology, fungicide resistance, and management recommendations.

    PMID:40403277 | DOI:10.1094/PDIS-01-25-0117-SR

  • Discovering leaf and stripe rust resistance in soft red winter wheat through genome-wide association studies 

    John W Bagwell

    Plant Genome. 2025 Jun;18(2):e70055. doi: 10.1002/tpg2.70055.

    ABSTRACT

    Leaf rust (LR) and stripe rust (YR), which are caused by Puccinia triticina and Puccinia striiformis, respectively, are among the most devastating wheat rusts worldwide. These diseases can be managed by using genetically resistant cultivars, an economical and environmentally safer alternative to fungicides. Over 100 and 80 Lr and Yr resistance genes have been discovered, respectively; however, rust pathogens are overcoming introduced resistance genes in the southeastern United States. Genome-wide association study has emerged as a valuable tool to identify new LR and YR resistance loci. In this study, a panel of 263 soft red winter wheat genotypes was evaluated for LR and YR severity in Plains, GA, and Williamson, GA, in a randomized complete block design of two replicates during 2019 and 2021-2023. Also, LR and YR infection types were assessed on seedlings at the three leaf stage in three greenhouse trials. A total of 26 significant quantitative trait loci (QTL) explaining 0.6%-30.8% phenotypic variance (PV) was detected by at least two of the five GAPIT models (BLINK, CMLM, FarmCPU, GLM, and MLM) tested. Nine major QTL included QLrYr-2A.1 linked to single-nucleotide polymorphism S2A_20855466, which had the highest overall PV (30.8%) for response to both rust pathogens in the field. Using the Chinese Spring Reference Genome Version 1.0, we detected 16 candidate genes, and four known R genes and QTL overlapped two major QTL. Of these QTL, 16 are likely novel genetic loci with potential for marker-assisted selection.

    PMID:40495572 | DOI:10.1002/tpg2.70055

  • Discovery of iridoid cyclase completes the iridoid pathway in asterids 

    Maite Colinas

    Nat Plants. 2025 Oct 3. doi: 10.1038/s41477-025-02122-6. Online ahead of print.

    ABSTRACT

    Iridoids are specialized monoterpenes ancestral to asterid flowering plants1,2 that play key roles in defence and are also essential precursors for pharmacologically important alkaloids3,4. The biosynthesis of all iridoids involves the cyclization of the reactive biosynthetic intermediate 8-oxocitronellyl enol. Here, using a variety of approaches including single-nuclei sequencing, we report the discovery of iridoid cyclases from a phylogenetically broad sample of asterid species that synthesize iridoids. We show that these enzymes catalyse formation of 7S-cis-trans and 7R-cis-cis nepetalactol, the two major iridoid stereoisomers found in plants. Our work uncovers a key missing step in the otherwise well-characterized early iridoid biosynthesis pathway in asterids. This discovery unlocks the possibility to generate previously inaccessible iridoid stereoisomers, which will enable metabolic engineering for the sustainable production of valuable iridoid and iridoid-derived compounds.

    PMID:41044409 | DOI:10.1038/s41477-025-02122-6

  • Dr. Diane Okamuro Gather & Grow Webinar

    Gather & Grow Webinar: What is it Like to be a Program Manager at NSF?

    Dr. Diane Okamuro, National Science Foundation Program Manager

    April 17, 2025 | Noon – 1PM

    Join Zoom

     

    Dr. Diane Jofuku Okamuro is a Program Director for the Plant Genome Research Program (PGRP) at the National Science Foundation, Directorate for Biological Sciences (BIO), Division of Integrative Organismal Systems. The PGRP is broad in scope and supports functional genomics tool development and basic discovery research on a genome-wide scale that will provide new insights into plant processes that are important to the U.S. economy. The PGRP Cluster also manages the Plant Genome Research Postdoctoral Fellowships program which is part of the BIO-wide Postdoctoral Research Fellowships in Biology program. In addition, she currently serves on the Working Group for the Biology Integration Institutes (BII) program which supports interdisciplinary, collaborative teams that perform research, education and training on critical questions that span multiple disciplines within and beyond biology.
    Dr. Okamuro received her Ph.D. in Biology from UCLA and is a plant molecular geneticist by training. She has broad-based experience in cutting-edge functional genomics technologies and has held research and management positions in both academia and industry prior to joining NSF in 2005.

  • Dr. Donglin Zhang recently named a 2024 Plant Biotechnology Fellow by the American Society for Horticultural Sciences!

    Congratulations to Dr. Donglin Zhang for recently being named a 2024 Plant Biotechnology Fellow by the American Society for Horticultural Sciences!

    Fellows of the Society are recognized for outstanding contributions to horticulture in one or more of the following areas: research, teaching, administration, or extension on a state, national, and/or international level; exhibition of leadership in horticultural business or industry pertinent to and compatible with the objectives of the Society; and noteworthy contributions to ASHS objectives (“to promote and encourage national and international interest in scientific research and education in horticulture in all its branches”). This may be demonstrated by the nominee’s direct and effective participation in the affairs and activities of the Society (including its Regional Groups) and/or by active involvement in the affairs of other allied organizations having objectives essentially the same as those of ASHS (including international organizations and those in countries other than the United States).

    Election as a Fellow of the Society is the highest honor that ASHS can bestow on its members, in recognition of truly outstanding contributions to horticulture and the Society.

    Congratulations, Dr. Zhang!

  • Dr. Rishi Masalia Gather & Grow Webinar

  • Draft genome assemblies of 38 Aspergillus parasiticus isolates collected from South Georgia crop fields 

    Sunil S Gangurde

    Microbiol Resour Announc. 2025 Sep 12:e0008325. doi: 10.1128/mra.00083-25. Online ahead of print.

    ABSTRACT

    Aspergillus parasiticus is a fungus recognized for producing highly carcinogenic mycotoxins. In this study, we collected 38 isolates of A. parasiticus from fields in South Georgia. We performed whole genome re-sequencing and developed 38 draft genome assemblies of A. parasiticus. The average genome size was 38.7 Mb, with larger genomes (~40 Mb) found in peanut fields in Turner County. Scaffold N50 was recorded highest for isolates collected from the corn fields of Tifton. The average BUSCO completeness score for these assemblies was 99.1%. The genome sequences generated for these 38 isolates will serve as a valuable genomic resource for the community working on aflatoxin mitigation strategies in crops.

    PMID:40938094 | DOI:10.1128/mra.00083-25

  • Drought adaptation index (DAI) based on BLUP as a selection approach for drought-resilient switchgrass germplasm 

    Shiva Om Makaju

    Front Genet. 2025 Aug 25;16:1626083. doi: 10.3389/fgene.2025.1626083. eCollection 2025.

    ABSTRACT

    This study introduces a Drought Adaptation Index (DAI), derived from Best Linear Unbiased Prediction (BLUP), as a method to assess drought resilience in switchgrass (Panicum virgatum L.). A panel of 404 genotypes was evaluated under drought-stressed (CV) and well-watered (UC) conditions over four consecutive years (2019-2022). BLUP-estimated biomass yields were used to calculate the DAI, which enabled classification of genotypes into four adaptation groups: very well-adapted, well-adapted, adapted, and unadapted. The DAI was compared with conventional drought tolerance indices, including the Stress Susceptibility Index (SSI), Stress Tolerance Index (STI), Geometric Mean Productivity (GMP), and Yield Stability Index (YSI). Correlation analyses demonstrated strong agreement between DAI and these indices, supporting its validity and consistency. Biplot analyses using the Genotype plus Genotype-by-Environment Interaction (GGE) and Additive Main Effects and Multiplicative Interaction (AMMI) models revealed significant genotype-by-environment interactions (GEI) and identified J222.A, J463.A, and J295.A. A as high-performing genotypes, with J222.A exhibiting greater yield stability across treatments and years. Additionally, DAI isoline curves provided a graphical representation of differential genotype performance under drought and control conditions. These visualizations aided in distinguishing genotypes with stable and superior biomass yield across contrasting environments. Overall, the BLUP-based DAI is a robust and practical selection tool that improves the accuracy of identifying drought-resilient, high-yielding switchgrass genotypes. Its integration into breeding programs offers a comprehensive framework for improving biomass productivity and stress adaptation under variable climatic conditions. The application of DAI supports the development of climate-resilient cultivars and contributes to sustainable bioenergy and forage production systems.

    PMID:40927363 | PMC:PMC12414770 | DOI:10.3389/fgene.2025.1626083

  • Engineering chromosome number in plants 

    Feng Zhang

    Science. 2025 Nov 20;390(6775):786-787. doi: 10.1126/science.aec7902. Epub 2025 Nov 20.

    ABSTRACT

    Chromosome engineering produces a reduced eight-chromosome karyotype in Arabidopsis thaliana.

    PMID:41264719 | DOI:10.1126/science.aec7902

  • Enzymatic epimerization of monoterpene indole alkaloids in kratom 

    Allwin McDonald

    Nat Chem Biol. 2025 Jul 16. doi: 10.1038/s41589-025-01970-9. Online ahead of print.

    ABSTRACT

    Monoterpene indole alkaloids (MIAs) are a large, structurally diverse class of bioactive natural products. These compounds are biosynthetically derived from a stereoselective Pictet-Spengler condensation that generates a tetrahydro-β-carboline scaffold characterized by a 3S stereocenter. However, a subset of MIAs contains a noncanonical 3R stereocenter. Here we report the basis for 3R-MIA biosynthesis in Mitragyna speciosa (kratom). We discover the presence of the iminium species (20S)-3-dehydrocorynantheidine, which supports isomerization of 3S to 3R via oxidation and stereoselective reduction downstream of the initial Pictet-Spengler condensation. Isotopologue feeding experiments identify the sites for downstream MIA pathway biosynthesis as well as the oxidase/reductase pair that catalyzes this epimerization. This oxidase/reductase pair has broad substrate specificity, suggesting that this pathway may be responsible for the formation of many 3R-MIAs and downstream spirooxindole alkaloids in kratom. The elucidation of this epimerization mechanism allows biocatalytic access to a range of pharmacologically active spirooxindole alkaloid compounds.

    PMID:40670688 | DOI:10.1038/s41589-025-01970-9

  • Estimating Hospitalization Expenditures Associated with Chronic Diseases and Multimorbidity for Older Adults – Guangzhou City, Guangdong Province, China, 2017-2019 

    Fei Zhao

    China CDC Wkly. 2025 Aug 1;7(31):1031-1037. doi: 10.46234/ccdcw2025.175.

    ABSTRACT

    WHAT IS ALREADY KNOWN ABOUT THIS TOPIC?: Chronic diseases and multimorbidity impose substantial burdens on healthcare systems globally, particularly in aging populations, resulting in elevated healthcare utilization rates and increased expenditures.

    WHAT IS ADDED BY THIS REPORT?: This study validates previous research findings using an extensive administrative database from a major city in South China. Additionally, it provides comprehensive estimates of annual hospitalization expenditures per patient associated with chronic diseases and multimorbidity patterns among older adults, elucidating the economic burden and cost variations across specific diseases and multimorbidity combinations. Cancer, cerebrovascular disease (CVD), and heart disease – whether occurring individually or in conjunction with other chronic conditions, particularly within complex multimorbidity patterns – were associated with substantial annual hospitalization expenditures and significant healthcare resource utilization.

    WHAT ARE THE IMPLICATIONS FOR PUBLIC HEALTH PRACTICE?: Disease burden studies provide critical evidence for prioritizing public health policies and targeted interventions. Policymakers should implement comprehensive prevention strategies, evidence-based interventions, appropriate reimbursement policies, and integrated management approaches to control disease progression and reduce healthcare expenditures.

    PMID:40831617 | PMC:PMC12360313 | DOI:10.46234/ccdcw2025.175

  • Ethylene-releasing plant growth regulators promote ripening initiation by stimulating sugar, acid and anthocyanin metabolism in blueberry (Vaccinium ashei) 

    Tej P Acharya

    BMC Plant Biol. 2025 Jun 5;25(1):766. doi: 10.1186/s12870-025-06799-x.

    ABSTRACT

    BACKGROUND: Fruit ripening is a coordinated process that leads to an increase in sugars, decrease in acids and accumulation of pigments. Blueberry fruit exhibit an atypical climacteric ripening behavior. These fruit display an increase in respiration and ethylene production during ripening, however ethylene synthesis is developmentally regulated. In this study, the effect of ethylene on blueberry fruit ripening was investigated via preharvest applications of ethylene-releasing plant growth regulators (PGRs), ethephon and 1-aminocyclopropane 1-carboxylic acid (ACC), in one southern highbush cultivar, Miss Lilly in 2019, and two rabbiteye cultivars, Premier and Powderblue in 2019 and 2020. Further, the effects of these two PGRs on fruit metabolism during ripening in the two rabbiteye cultivars, and postharvest fruit quality in all three cultivars were evaluated.

    RESULTS: Both PGRs increased ethylene evolution within 1-3 days after treatment (DAT). Ethephon and ACC applications increased the rate of ripening within 5 DAT in all cultivars, and increased ripe (blue) fruit by up to 35% and 29%, respectively between 7 to 10 DAT compared to the control. Metabolite analysis revealed that PGR treatments resulted in an immediate, but transient increase in sucrose, glucose and fructose, in ‘Premier’ at 3 DAT. Malate decreased at 3 DAT in response to both PGR treatments in ‘Premier’, and at 5 DAT in ethephon treatment in both cultivars. A rapid increase in the concentration of multiple anthocyanins was noted at 3 DAT in response to both PGRs in ‘Premier’ and ‘Powderblue’. Gene expression analysis revealed an increase in transcript abundance of VACUOLAR INVERTASE (vINV) and multiple anthocyanin biosynthesis genes between 1 and 3 DAT after PGR treatments in both cultivars, supporting the metabolite changes. However, the alteration in fruit metabolite concentrations were not sustained, and similar in PGR-treated fruit compared to the control in ripe fruit harvested at 10 DAT. Postharvest fruit quality attributes, such as firmness, total soluble solids, titratable acidity, and visual quality, were not consistently affected by the PGR applications compared to control treatments across all cultivars. A decrease in fruit weight was noted, although not consistently, in response to PGR treatments.

    CONCLUSIONS: Overall, this study demonstrates that ethylene plays a crucial role in promoting ripening via rapid and transient stimulation of sugar, acid and anthocyanin metabolism. The promotion of fruit ripening by ethylene-releasing PGRs can lead to minimal but inconsistent changes in fruit quality attributes during postharvest storage.

    PMID:40474063 | DOI:10.1186/s12870-025-06799-x

  • Evaporative cooling signals for wound healing in plants 

    Joseph Balem

    bioRxiv [Preprint]. 2025 May 28:2025.05.23.655667. doi: 10.1101/2025.05.23.655667.

    ABSTRACT

    Repairing a damaged body part is critical for the survival of any organism. In plants, tissue damage induces rapid responses that activate defense, regeneration and wound healing. While early wound signaling mediated by phytohormones, electrical signals and reactive oxygen species is well-characterized, the mechanisms governing the final stages of wound healing remain poorly understood. Here, we show that wounding in Arabidopsis leaves induces localized cooling, likely due to evaporative water loss, accompanied by the activation of cold-responsive genes. The subsequent disappearance of localized cooling and deactivation of cold-responsive genes serve as a quantitative marker of wound healing. Based on these observations, we developed a workflow by leveraging computer vision and deep learning to monitor the dynamics of wound healing. We found that CBFs transcription factors relay injury-induced cooling signal to wound healing. Thus, our work advances our understanding of tissue repair and provides a tool to quantify wound healing in plants.

    PMID:40502075 | PMC:PMC12154623 | DOI:10.1101/2025.05.23.655667

  • Everyday norms have become more permissive over time and vary across cultures 

    Kimmo Eriksson

    Commun Psychol. 2025 Oct 7;3(1):145. doi: 10.1038/s44271-025-00324-4.

    ABSTRACT

    Every social situation that people encounter in their daily lives comes with a set of unwritten rules about what behavior is considered appropriate or inappropriate. These everyday norms can vary across societies: some societies may have more permissive norms in general or for certain behaviors, or for certain behaviors in specific situations. In a preregistered survey of 25,422 participants across 90 societies, we map societal differences in 150 everyday norms and show that they can be explained by how societies prioritize individualizing moral foundations such as care and liberty versus binding moral foundations such as purity. Specifically, societies with more individualistic morality tend to have more permissive norms in general (greater liberty) and especially for behaviors deemed vulgar (less purity), but they exhibit less permissive norms for behaviors perceived to have negative consequences in specific situations (greater care). By comparing our data with available data collected twenty years ago, we find a global pattern of change toward more permissive norms overall but less permissive norms for the most vulgar and inconsiderate behaviors. This study explains how social norms vary across behaviors, situations, societies, and time.

    PMID:41057696 | DOI:10.1038/s44271-025-00324-4

  • Factors underlying a latitudinal gradient in the S/G lignin monomer ratio in natural poplar variants 

    Weiwei Zhu

    Proc Natl Acad Sci U S A. 2025 Aug 26;122(34):e2503491122. doi: 10.1073/pnas.2503491122. Epub 2025 Aug 20.

    ABSTRACT

    The chemical composition of wood plays a pivotal role in the adaptability and structural integrity of trees. However, few studies have investigated the environmental factors that determine lignin composition and its biological significance in plants. Here, we examined the lignin syringyl-to-guaiacyl (S/G) ratio in members of a Populus trichocarpa population sourced from their native habitat and conducted a genome wide association study to identify genes linked to lignin formation. Our results revealed many significant associations, suggesting that lignin biosynthesis is a complex polygenic trait. Additionally, we found an increase in the S/G ratio from northern to southern geographic origin of the trees sampled, along with a corresponding metabolic and transcriptional reprogramming of xylem cell wall biosynthesis. Further molecular analysis identified a mutation in a cell wall laccase genetically associated with higher S/G ratios that predominate in trees from warmer lower latitudes. Collectively, our findings suggest that lignin heterogeneity arises from an evolutionary process enabling poplar adaptation to different climatic challenges.

    PMID:40833412 | DOI:10.1073/pnas.2503491122

  • FFAR Announces 26 Awardees of FFAR Fellows Program naming Shreena Pradhan

    WASHINGTON (August 11, 2021) – Climate change, a growing population and evolving pests and pathogens threaten the security of our global food supply. Employers need trained scientists to conduct research that helps farms and food systems adapt to these challenges. The Foundation for Food & Agriculture Research (FFAR) and North Carolina State University are excited to announce the 26 students selected for the 2021 FFAR Fellows Program. This unique three-year program provides professional development training and mentorship to doctoral students conducting research in alignment with FFAR’s six Challenge Areas.

  • FX-Cell: a method for single-cell RNA sequencing on difficult-to-digest and cryopreserved plant samples 

    Xin Ming

    Nat Methods. 2025 Nov 27. doi: 10.1038/s41592-025-02900-2. Online ahead of print.

    ABSTRACT

    Single-cell RNA sequencing in plants requires the isolation of high-quality protoplasts-cells devoid of cell walls. However, many plant tissues and organs are resistant to enzymatic digestion, posing a significant barrier to advancing single-cell multi-omics in plant research. Furthermore, for field-grown crops, the lack of immediate laboratory facilities presents another major challenge for timely protoplast preparation. Here, to address these limitations, we developed FX-Cell and its derivatives, FXcryo-Cell and cryoFX-Cell, to enable single-cell RNA sequencing with both difficult-to-digest and cryopreserved plant samples. By optimizing the fixation buffer and minimizing RNA degradation, our approach ensures efficient cell wall digestion at high temperatures while maintaining high-quality single cells, even after long-term storage at -80 °C, and circumvents use of nuclei, which are not representative of the pool of translatable messenger RNAs. We successfully constructed high-quality cell atlases for rice tiller nodes, rhizomes of wild rice and maize crown roots grown under field conditions. Moreover, these methods enable the accurate reconstruction of plant acute wounding responses at single-cell resolution. Collectively, these advancements expand the applicability of plant single-cell genomics across a wider range of species and tissues, paving the way for comprehensive Plant Cell Atlases for plant species.

    PMID:41310055 | DOI:10.1038/s41592-025-02900-2

  • Gene Expression Differentiation Is Consistent with Local Adaptation across an Elevational Gradient in Drummond’s Rockcress (Boechera stricta) 

    Shelby L Tisinai

    J Hered. 2025 Oct 15:esaf081. doi: 10.1093/jhered/esaf081. Online ahead of print.

    ABSTRACT

    A central goal of evolutionary biology is to understand the mechanisms conferring adaptation. Gene expression is sensitive to environmental variability; thus, investigating gene expression differentiation among populations may reveal signatures of selection from predictable environmental conditions. Environmental pressures that covary with elevation gain (e.g., temperature) result in stark environmental differences along short distances. The phenological and life history traits of plants inhabiting elevational gradients might track these variables, providing an opportunity for testing hypotheses. Boechera stricta occupies a steep elevation gradient in the Rocky Mountains. Here, we grew F3 seeds from at least two genotypes each from five populations of B. stricta in a greenhouse. Analysis of leaf RNAseq data permitted tests of these hypotheses: 1) populations exhibit significant among population genetic variation in gene expression; 2) differentiation in gene expression (QST) exceeds neutral expectations (FST); and 3) the putative functions of differentially expressed genes are predicable based on a priori knowledge of environmental pressures that vary with elevation. Differentiation in gene expression (average QST = 0.53) significantly exceeded neutral differentiation (average FST = 0.17), implicating selection as a potential cause of genetically divergent patterns of gene expression. The putative functions of differentially expressed genes covarying with elevation were enriched for biological processes related to conditions that vary with elevation (circadian rhythm, response to light, chloroplast organization, and vegetative to reproductive meristem transitions). This study reveals considerable differentiation in gene expression, which may provide a mechanism for rapid adaptation to local environmental conditions in this and other species.

    PMID:41092278 | DOI:10.1093/jhered/esaf081

  • Genetic and environmental influences on the distributions of three chromosomal drive haplotypes in maize 

    Meghan J Brady

    bioRxiv [Preprint]. 2025 May 27:2025.05.22.655462. doi: 10.1101/2025.05.22.655462.

    ABSTRACT

    Meiotic drive elements are regions of the genome that are transmitted to progeny at frequencies that exceed Mendelian expectations, often to the detriment of the organism. In maize there are three prevalent chromosomal drive elements known as Abnormal chromosome 10 (Ab10), K10L2, and the B chromosome. There has been much speculation about how these drivers might interact with each other and the environment in traditional maize landraces and their teosinte ancestors. Here we used genotype-by-sequencing data to score more than 10,000 maize and teosinte lines for the presence or absence of each driver. Less than ~0.5% of modern inbred lines carry chromosomal drivers. Among individuals from 5331 open-pollinated landraces, 6.32% carried Ab10, 5.16% carried K10L2, and 12.28% carried at least one B chromosome. Using a GWAS approach we identified unlinked loci that associate with the presence or absence of the selfish genetic elements. Many genetic modifiers are positively associated with the drivers, suggesting that there may have been selection for alleles that ameliorate their negative fitness consequences. We then assessed the contributions of population structure, associated loci, and the environment on the distribution of each chromosomal driver. There was no significant relationship between any chromosomal driver and altitude, contrary to conclusions based on smaller studies. Our data suggest that the distribution of the major chromosomal drivers is primarily influenced by neutral processes and the deleterious fitness consequences of the drivers themselves. While each driver has a unique relationship to genetic background and the environment, they are largely unconstrained by either.

    PMID:40501570 | PMC:PMC12154789 | DOI:10.1101/2025.05.22.655462