Arginine Delays Postharvest Softening of Button Mushroom (Agaricus bisporus) via Lipid Metabolism Regulation

Postharvest storage and quality maintenance represent significant constrains for the marketability and long-distance exportation of button mushroom (<i>Agaricus bisporus</i>). Protective techniques such as arginine application has been demonstrated to extend the shelf life of button mushroom. However, the underlying mechanism by which arginine mitigates postharvest softening in button mushroom require further elucidation. In this study, comprehensive physiology, metabolomics and transcriptomics analyses of button mushroom following arginine treatment were conducted to investigate its potential mechanisms of action. Physiological analysis showed that arginine treatment (1.5 g L^-1) markedly alleviated the postharvest softening of button mushroom, resulting in a 23.8% increase in firmness, reduced malondialdehyde (MDA) content, suppressed activities of phenylalanine ammonia-lyase (PAL) and polyphenol oxidase (PPO), and maintained elevated superoxide dismutase (SOD) activity. Integrated transcriptomic and metabolomic analyses demonstrated that arginine application significantly altered lipid-related metabolites, including free fatty acids, lysophosphatidylcholine (LPC), lysophosphatidylethanolamine (LPE) and phosphatidylcholine (PC). Notably, arginine treatment increased the levels of unsaturated fatty acids (UFAs). Transcriptomic analysis further revealed that differentially expressed genes (DEGs) were predominantly enriched in lipid metabolism pathways following arginine treatment. Specifically, arginine application stimulated the lipid metabolism by upregulating genes associated with fatty acid desaturation (FAD), while downregulating genes related to phospholipases A2 (PLA2). These findings collectively demonstrate that arginine effectively mitigates postharvest softening of button mushroom by modulating lipid metabolism.