Impact of DNA methylation-inhibition stress on barley (Hordeum Vulgare L.) seed germination: cytophysiological and molecular assessment

초록

DNA methylation is an epigenetic mechanism regulating plant development and stress responses. This study evaluates how DNA methylation inhibition affects the phenotype, methylome, and transcriptome during early germination of barley (Hordeum vulgare L.). Seeds were exposed to 1,000 μM zebularine, a DNA methylation inhibitor, and germinated for up to 24 h. Compared to water-treated controls, inhibitor-treated seeds showed significantly longer radicle length. To understand the molecular basis of these phenotypic changes, we conducted methylome and transcriptome analyses. Whole-genome bisulfite sequencing revealed altered methylation patterns, with a slight reduction in CpG methylation (82.0% to 81.5%) and minor increases in CHG and CHH contexts. Transcriptome profiling identified 524 differentially expressed genes (DEGs). Gene Ontology (GO) enrichment indicated marked suppression of genes in the ‘extracellular region’ (GO:0005576) and those linked to ‘alpha-amylase inhibitor activity’ (GO:0015066) and ‘serine-type endopeptidase inhibitor activity’ (GO:0004867). These transcriptomic changes aligned with α-amylase activity assays. In summary, DNA methylation inhibitors as a chemical stress that promotes radicle elongation and enhances metabolic and stress-response gene expression during early barley germination, highlighting the dynamic role of DNA methylation in plant adaptation.

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