Jasmonic acid and PpeMYC2 regulate peach fruit ripening by controlling polyamine levels and anthocyanin biosynthesis

This is the authors' abstract. We don't add key points for this paper.

Jasmonic acid (JA) and polyamines (PAs) are key regulators of fruit ripening, yet their functional association remains largely unresolved. Here, we demonstrate that exogenous methyl jasmonate (MeJA) application markedly reduces PA accumulation and accelerates peach (Prunus persica L.) fruit ripening. Transcriptomic analysis revealed significant upregulation of peach polyamine oxidase1 (PpePAO1), a key gene in PA catabolism, following MeJA treatment. Using the PpePAO1 promoter as bait, we identified the JA signaling transcription factor myeloblastosis family 2 (PpeMYC2). MeJA treatment suppressed PpeMYC2 expression, and subsequent yeast one-hybrid (Y1H), electrophoretic mobility shift assay (EMSA), and dual-luciferase assay confirmed that PpeMYC2 directly binds to the PpePAO1 promoter to repress its transcriptional activity. Silencing PpeMYC2 led to decreased PA levels and accelerated fruit ripening, whereas PpeMYC2 overexpression produced the opposite effect. Additionally, PpeMYC2 activated the arginine decarboxylase (PpeADC1) promoter, thereby enhancing PA biosynthesis. Beyond PA regulation, silencing PpeMYC2 significantly increased anthocyanin accumulation by relieving its repression of dihydroflavonol 4-reductase (PpeDFR), a key gene in anthocyanin biosynthesis. Collectively, these findings reveal that JA promotes peach fruit ripening by lowering PA accumulation and stimulating anthocyanin synthesis through PpeMYC2-mediated transcriptional control. This study provides mechanistic evidence that JA regulates fruit ripening through direct control of PA metabolism and identifies PpeMYC2 as a central node integrating JA, PA, and anthocyanin pathways in peach fruit.