Metabolomics revealed that salicylic acid treatment enhanced the post-harvest quality of 'Fengtang' plum by activating the phenylpropanoid metabolism and antioxidant system

While the effects of postharvest salicylic acid (SA) application on horticultural product quality are well documented, the underlying molecular mechanisms and specific protective functions of SA in 'Fengtang' plum remain unclear. We evaluated the influence of SA on antioxidant metabolism, phenylpropanoid metabolism, and overall metabolite profiles in this cultivar. Fruits were immersed in SA solutions (0, 0.5, 1.5, and 3 mmol L⁻¹) and stored at 4 °C for 60 d.Treatment with 1.5 mmol L⁻¹ SA most effectively preserved fruit firmness, soluble solids content, and titratable acidity, while simultaneously enhancing antioxidant capacity hrough activation of key phenylpropanoid pathway enzymes (PAL, C4H, 4CL, CAD, POD), leading to increased accumulation of total phenolics, total flavonoids, and lignin. Metabolomic profiling identified 1568 metabolites, and KEGG enrichment analysis highlighted "Glutathione metabolism" and "Phenylpropanoid biosynthesis" as the central pathways affected by SA. The SA application markedly upregulated key differential metabolites, such as reduced glutathione (GSH), phenolic acids ( p -Coumaric acid, Caffeic acid), and flavonoids. Therefore, SA effectively delayed postharvest senescence in 'Fengtang' plum through the synergistic enhancement of antioxidant defense and phenylpropanoid metabolism, forming an integrated defense network to maintain fruit quality during cold storage. These results provide a metabolomic foundation for using SA as a green preservative in plum fruit storage.