Abstract

Climacteric ethylene is an early trigger for chilling injury in melting-flesh peach. • PpPLD2 is involved in mediating phosphatidylcholine-to-phosphatidic acid conversion. • PpERF110/113 directly activate PpPLD2 via binding to the GCC-box. • The ethylene–ERF–PLD axis mediates membrane integrity and chilling injury in peach. Chilling injury (CI) severely restricts the postharvest storage life and commercial value of climacteric peach fruit. This study investigated the molecular mechanisms underlying CI development in 'Hujingmilu' peach fruit, a typical melting-flesh cultivar characterized by robust ethylene biosynthesis, focusing on the interplay between ethylene signaling and membrane lipid metabolism. Our results revealed that endogenous ethylene evolution peaked at 21 d of cold storage, preceding the manifest outbreak of CI symptoms and suggesting its role as a potential trigger within this high-ethylene genotype. Transcriptomic and biochemical analyses identified PpPLD2 as a pivotal metabolic node, with its expression highly synchronized with phosphatidylcholine (PC) degradation and phosphatidic acid (PA) accumulation. Two cold-responsive transcription factors, PpERF110 and PpERF113, were identified as downstream transducers of ethylene signaling. The results of dual-luciferase, yeast one-hybrid, and electrophoretic mobility shift assays demonstrated that both PpERFs directly bind to the GCC-box motif within the PpPLD2 promoter to activate its transcription. Transient overexpression of PpERF110 or PpERF113 in peach fruit upregulated PpPLD2 expression, decreased PC, content and increased PA levels and the PA/PC ratio, thereby exacerbating tissue damage, whereas their silencing mitigated these effects. Furthermore, ectopic expression assays in Nicotiana benthamiana revealed that PpERF110 more severely exacerbated ROS-mediated oxidative damage than PpERF113, as evidenced by higher ROS accumulation and disrupted cellular redox status and lipid homeostas