Phosphatidic acid from the PLC-DGK pathway mediates the lipid remodeling and the ethylene signaling restriction to confer chilling tolerance in peaches

Abstact Peaches are highly susceptible to chilling injury (CI), with phosphoatidic acid being essential for cold response; however underlying mechanism remains largely uncovered. In this study, we investigated the regulatory mechanisms of exogenous phosphatidic acid (PA 16:0–18:2) in mitigating CI symptoms in ‘Zhongtao No.9’ peaches stored at 0 °C for 35 d. Physiological assessments showed that exogenous PA treatment significantly reduced the internal browning index, relative electrolyte leakage, and malondialdehyde content, while effectively preserving fruit firmness. Furthermore, PA enhanced the cellular antioxidant capacity by maintaining higher levels of phenolics and flavonoids, boosting peroxidase activity, and suppressing polyphenol oxidase activity. Integrated untargeted lipidomics and transcriptional profiling demonstrated that PA treatment dynamically drives membrane lipid remodeling. It optimized the fatty acid profiles by promoting polyunsaturated fatty acids and suppressing saturated fatty acids. Mechanistically, exogenous PA, like its specific inhibitor (D5919), triggered a feedback inhibition on PA generation from the phospholipase C–diacylglycerol kinase (PLC-DGK) route, while transcriptionally activating the PA depletion into PA-DAG-TAG flux to stabilize the membrane structure. Meantime, PA significantly suppressed the deleterious ethylene pathway while reinforcing the cold response. PA application down-regulated key ethylene biosynthetic genes ( PpACS1 and PpACO1 ), leading to a sharply reduced the ethylene release rate, while up-regulating transcript levels of the master cold-responsive hub PpCBF3 and multiple negative regulators of ethylene signaling, including PpCTR1 and PpETR1 . PA could bind to recombinant PpCTR1 in vitro and enhance the interaction between PpCTR1 and PpETR1 in vivo , thereby repressing ethylene response. Conclusively, our findings demonstrate that exogenous PA effectively confers chilling tolerance in peaches through tightly coupled lipid metabolic remodeling and specific lipid-hormone signaling crosstalk, offering novel strategic targets for postharvest preservation.