The molecular mechanisms underlying DNA methylation-associated environmental adaptation in poplar are preliminarily revealed, providing potential genetic targets for breeding climate-resilient trees.
Abstract
Populus deltoides is a key species for industrial timber and ecological construction in temperate regions, where increasingly frequent and persistent heat waves pose serious challenges to its survival. However, the epigenetic mechanisms by which DNA methylation regulates environmental responses remain poorly understood. Here, whole-genome bisulfite sequencing and RNA-seq were performed on five P. deltoides genotypes grown in temperate and tropical regions. Results revealed that CG/CHG methylation stability is closely correlated with environmental sensitivity. Significant CG/CHG methylation variations may occur specifically in sensitive genotypes with large provenance-environment differences, thereby threatening the survival of P. deltoides by inhibiting the expression of key genes involved in life processes. CHH methylation variation may act as a potential epigenetic regulator of environmental adaptation. Promoter CHH-hypermethylation appears to represent a general response of P. deltoides under high-temperature and short-photoperiod (HS) stress, potentially regulating the expression of 56 genes to activate Ca2+ influx and heat shock proteins, repressing auxin, cytokinin, and cell cycle pathways, thereby initiating stress-protective responses. PdeCNGC13, PdeARF6, PdeLOG3, and PdeHSP15.7 were identified as potential regulatory genes of HS adaptation that are associated with DNA methylation. The mechanism of PdeLOG3 may involve HS-induced CHH-hypermethylation at its PdeLOG3 promoter, which may be associated with suppressed expression, reduced dihydrozeatin levels, and growth. This effect was partially reversed by 5-Azacytidine administration, accompanying increased cytokinin synthesis, enhanced antioxidant capacity, and coinciding with alleviation of HS stress. Our work preliminarily reveals the molecular mechanisms underlying DNA methylation-associated environmental adaptation in poplar, providing potential genetic targets for breeding climate-resilient trees.
These findings support a model in which repeated drought consistently recruits CHH methylation to reproducible gene-proximal TEs, where it is associated with maintenance of local TE repression despite continued activation of neighboring stress-responsive genes.
A near telomere-to-telomere genome assembly of Populus wilsonii, a montane tree species endemic to the eastern Hengduan Mountains, offers novel insights into how forest trees balance transient epigenetic flexibility with enduring genetic stability to survive accelerating climate change.
Xinxin Zhang, Jiajun Feng, Zeng Wang et al.· Plant Communications· 0 citations
Apyrases (APYs), nucleoside triphosphate-diphosphohydrolases, serve as critical enzymes in regulating extracellular ATP levels and maintaining biochemical homeostasis under stress conditions. Under the escalating pressures of global climate change, the adverse effects of rising temperatures and altered precipitation patterns on crop productivity have become increasingly severe. Chinese cabbage (Brassica rapa L. ssp. pekinensis, B.rapa), a globally significant cruciferous crop, faces substantial threats due to its high sensitivity to environmental stressors. Throughout its growth cycle, it is frequently subjected to various environmental stresses and exhibits high sensitivity to drought stress and temperature fluctuations. In this study, we systematically identified 13 APY genes in the B.rapa genome and conducted a comprehensive analysis of their phylogenetic relationships, conserved motifs, and cis-regulatory elements. qRT-PCR analysis further revealed distinct tissue-specific expression patterns of BrAPYs and their differential regulation under drought, extreme temperature, and cold stress conditions. These findings establish a molecular framework for understanding the stress-responsive functions of APYs in Chinese cabbage and highlight potential targets for enhancing stress tolerance through genetic improvement.
Yang Zhou, Jiangtao Du, Shanyu Li et al.· Frontiers in Plant Science· 0 citations
Genome-wide DNA-methylation revealed a progressive increase in the CHH context from Spring to Summer and Autumn, suggesting epigenetic reprogramming is happening over season and growing cycle, providing a genomic foundation for understanding how epigenetic memory contributes to phenology, developmental programming and long-term adaptation in long-lived plants.
Rosa Sanchez-Lucas, Joe He, Marcella Chirico et al.· Journal of Experimental Bota...· 0 citations
It is suggested that Al stress triggers genotype- and sequence-context-specific epigenomic reprogramming in rice, and that tolerance is associated with a targeted methylation response rather than a diffuse one.
J. Gallo-Franco, Chrystian C. Sosa, F. Johannes et al.· Frontiers in Plant Science· 0 citations
Soil salinization is a critical environmental challenge threatening plant survival. To adapt, certain plants have evolved tolerance to highly saline-alkali environments through long-term natural selection. Tamarix chinensis L., a typical halophyte with strong adaptability to salt and alkali stresses, serves as an essential germplasm resource and pioneer species for ecological conservation and remediation. However, the epigenetic mechanisms underlying its stress tolerance remain poorly understood. In this study, we systematically characterized the tolerance and genome-wide DNA methylation variations in T. chinensis under diverse salt and alkali stresses conditions. Phenotypic observations manifested severe leaf damage under 150 mM alkali stress over 10 days, whereas only slight injury occurred under 400 mM salt stress, indicating superior tolerance to salinity over alkalinity. MSAP analysis revealed that salt stress predominantly triggered genome-wide demethylation; conversely, alkali stress primarily induced hypermethylation, with both variations occurring mainly at CNG sites. Notably, DNA methylation alterations were more extensive under salt stress. Sequencing of methylation-variant bands yielded 17 stress-related sequences, eight of which are homologous to known stress-responsive genes. These findings provide a theoretical framework for dissecting differential epigenetic responses to salt and alkali stresses, facilitate the mining of resistance genes, and offer epigenetic references for the molecular breeding of T. chinensis to and ecological remediation of saline-alkaline lands.
Long Wang, Bo Li, Yue Wang et al.· Frontiers in Plant Science· 0 citations
