Category: Pub Med

Int J Mol Sci. 2025 Apr 23;26(9):3999. doi: 10.3390/ijms26093999.

ABSTRACT

The mechanisms underlying leaf variegation in the ornamental Ilex × ‘Solar Flare’ remain poorly understood. To investigate this phenomenon, we conducted a comprehensive characterization of its variegated leaves. Compared to green sectors, yellow sectors exhibited severe chloroplast structural abnormalities, including swollen chloroplasts, damaged thylakoid membranes, and reduced chloroplast numbers. These yellow sectors also showed significantly lower chlorophyll and carotenoid levels, along with a depletion of key chlorophyll precursors-protoporphyrin IX (Proto IX), magnesium protoporphyrin IX (Mg-Proto IX), and protochlorophyllide (Pchlide). Photosynthetic efficiency was significantly impaired. Comparative transcriptome analysis identified 3510 differentially expressed genes (DEGs) between yellow and green sectors. Key disruptions in chlorophyll biosynthesis included upregulated CHLD expression and downregulated CHLH and CHLG expression, leading to impaired chlorophyll synthesis. Additionally, chlorophyll degradation was accelerated by PAO upregulation. Defective chloroplast development in yellow sectors was associated with the downregulation of GLK1, GLK2, and thylakoid membrane-related genes (PsbC, PsbO, PsbR, PsaD, and PsaH). These molecular alterations likely drive the variegated phenotype of I. × ‘Solar Flare’. These observations advance our understanding of the genetic and physiological mechanisms regulating leaf variegation in this cultivar.

PMID:40362242 | PMC:PMC12071917 | DOI:10.3390/ijms26093999

Ecol Lett. 2025 May;28(5):e70134. doi: 10.1111/ele.70134.

ABSTRACT

Species’ distributions are changing around the planet as a result of global climate change. Most research has focused on shifts in mean climate conditions, leaving the effects of increased environmental variability comparatively underexplored. This paper proposes two new macroecological hypotheses-the variability damping hypothesis and the variability adaptation hypothesis-to understand how ecological dynamics and evolutionary history could influence biogeographic patterns being forced by contemporary large-scale climate change across all major ecosystems. The variability damping hypothesis predicts that distributions of species living in deep water environments will be least affected by increasing climate-driven temperature variability compared with species in nearshore, intertidal and terrestrial environments. The variability adaptation hypothesis predicts the opposite. Where available, we discuss how the existing evidence aligns with these hypotheses and propose ways in which they may be empirically tested.

PMID:40344332 | PMC:PMC12061546 | DOI:10.1111/ele.70134

Integr Comp Biol. 2025 May 8:icaf028. doi: 10.1093/icb/icaf028. Online ahead of print.

ABSTRACT

Climate change is simultaneously increasing atmospheric carbon dioxide concentrations ([CO2]) and temperatures. We conducted a multi-factorial growth chamber experiment to examine how these climate change factors interact to influence the expression of ecologically-relevant traits, clines in these traits, and natural selection on morphology and phenology of diverse accessions of Boechera stricta (Brassicaceae) sourced from a broad elevational gradient in Colorado, USA. Plastic shifts in a key allocation trait (root mass fraction) in response to temperature accord with the direction of selection for probability of flowering, indicating that plasticity in this trait could be adaptive. However, plasticity in a foliar functional trait (leaf dry matter content) in response to temperature and [CO2] did not align with the direction of selection, indicating that plasticity could reduce fitness based on plant carbon allocation strategies. For another ecologically-important phenotype, selection favors resource acquisitive trait values (higher specific leaf area) under elevated [CO2] and resource conservative trait values (lower specific leaf area) at lower [CO2], despite the lack of plasticity in this trait. This pattern of selection counters published reports that elevated [CO2] induces low specific leaf area but could enable plants to reproduce across a greater period of the growing season under increasingly warm climates. Indeed, warmer temperatures prolonged the duration of flowering. This plasticity is likely adaptive, as selection favored increased flowering duration in the higher temperature treatment level. Thus, the two major results that emerged from our study are that climate change could impose novel and unanticipated patterns of natural selection on plant traits and that plasticity in these traits can be a maladaptive response to stress.

PMID:40338630 | DOI:10.1093/icb/icaf028