Biology subjects

Yerushalmy, Y.

Publications and source records attributed to Yerushalmy, Y..

2 recordsLinked to original sources

bioRxiv2025

Methionine Triggers Metabolic, Transcriptional, and Epigenetic Reprogramming in Arabidopsis Leaves

Methionine (Met) is a central metabolite in plants, as it serves as a precursor for S-adenosylmethionine (SAM), a key methyl donor for epigenetic and metabolic processes. Met is also an essential amino acid that limits the nutritional value of plant-based diets. Understanding how altered Met levels affect the metabolome, transcriptome, and epigenetic regulation of plant leaves remains an open challenge. This study investigates the impact of ectopic Met accumulation in SSE Arabidopsis leaves of transgenic lines expressing a deregulated form of AtCGS (AtD-CGS) under the seed-specific phaseolin promoter. Unexpected activation of the phaseolin promoter in leaves led to AtD-CGS expression and variable Met accumulation among progeny, despite genetic homozygosity. High-Met (HM) plants showed elevated amino acid and sugar levels, enrichment of stress-related transcripts, and suppression of Met biosynthetic genes, while Low-Met (LM) plants showed reduced Met levels and increased non-CG DNA methylation, especially in centromeric and promoter regions. Integrated transcriptome and methylome analyses revealed that high Met levels were associated with the upregulation of stress hormone pathways (abscisic acid, jasmonate, salicylic acid, and ethylene), downregulation of key epigenetic regulators (e.g., MET1, CMTs), and broader transcriptional reprogramming. By contrast, low Met (LM) lines displayed similar expression levels of genes as control plants. Our findings reveal a complex regulatory network whereby Met accumulation reprograms metabolism, gene expression, and DNA methylation patterns. These results suggest feedback between sulfur-carbon metabolism, stress adaptation, and epigenetic control, positioning Met as both a nutrient and a signaling hub in plant physiology.

plant biology↗

bioRxiv2025

Elevated methionine induces DNA hypermethylation of transposable elements in Arabidopsis

Methionine (Met) is a key sulfur-containing amino acid and the precursor of S-adenosylmethionine (SAM), the universal methyl donor for DNA and histone methylation. While reduced SAM availability is known to cause DNA hypomethylation, the effects of elevated Met/SAM remain poorly understood. Here, we examined the Arabidopsis thaliana mto1 mutant, which accumulates Met and SAM due to a mutation in cystathionine {gamma}-synthase, the first committed enzyme of Met biosynthesis. Whole-genome bisulfite sequencing (WGBS) analysis revealed widespread hypermethylation in mto1, particularly in non-CG contexts (CHG and CHH), with the strongest changes in pericentromeric heterochromatin. Hypermethylation was concentrated in transposable elements (TEs), especially retrotransposon families such as Gypsy and Copia. Transcriptome profiling showed that TE-genes (TEGs) were broadly downregulated, consistent with reinforced TE silencing due to the hypermethylation. Despite these epigenetic changes, expression of core DNA methyltransferases and demethylases was largely unchanged, suggesting that increased SAM availability enhances enzymatic activity rather than gene expression. In addition, [~]25% of protein-coding genes were differentially expressed in mto1, though most changes were not directly linked to promoter- or gene-body methylation. Instead, the strong bias toward hypermethylation of TEs and repression of TEGs suggests that elevated Met/SAM primarily affects gene expression indirectly. Together, these findings demonstrate that an excess of Met/SAM reinforces heterochromatic DNA methylation and transposon silencing, providing new insights into the connection between amino acid metabolism and epigenetic regulation in plants.

plant biology↗