Methyl jasmonate (MeJA) has emerged as a promising agent for mitigating chilling injury (CI) in peach fruit (Prunus persica); however, the molecular mechanisms underlying the role of MYC2, a key transcriptional regulator of jasmonic acid (JA) signaling, in mediating cold adaptation remain largely unexplored. In this study, we demonstrated that MeJA treatment effectively alleviated CI in peach fruit, accompanied by enhanced ethylene biosynthesis, elevated accumulation of polyphenols and flavonoids, and a marked reduction in reactive oxygen species levels. Using DNA affinity purification sequencing and transactivation assays, we identified PpMYC2.1 as a central regulator that directly activates key genes involved in ethylene-mediated fruit softening (PpIAA1, PpHB.G7, PpERF61, PpPL1, PpPG2, and PpXTH2) and phenylpropanoid metabolism (PpPAL1, Pp4CL, PpCHI3, and PpCHS). Stable overexpression of PpMYC2.1 in tomato (Solanum lycopersicum) significantly enhanced fruit tolerance to cold stress. Meanwhile, transient overexpression or silencing in peach fruit upregulated or downregulated the expression of its target genes, confirming its positive regulatory role in cold stress response. Mechanistically, MeJA downregulated the expression of transcriptional repressors PpJAZ2 and PpJAZ4, thereby alleviating their suppression of PpMYC2.1-mediated transactivation. Collectively, these findings reveal a previously uncharacterized JA-responsive transcriptional module, PpJAZ2/4-PpMYC2.1, that orchestrates cold stress adaptation in peach fruit, offering novel insights into postharvest preservation strategies for climacteric fruit.

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