Melatonin and Selenium Enhance Strawberry Resistance to Botrytis cinerea via Integrated Transcriptome-Metabolome Analysis.

This study fills a critical knowledge gap by elucidating the mechanisms of melatonin (MT) and selenium (Se) in enhancing strawberry resistance to Botrytis cinerea through integrated physiological, biochemical, transcriptomic, and metabolomic analyses, providing an eco-friendly strategy for postharvest disease management. Combined MT (0.5 mmol/L) and sodium selenite (25 mg/L) exhibited a strong inhibitory effect on B. cinerea, reducing colony diameter to 1.05 cm with an inhibition rate of 93.67%, compared with MT (14.08%) alone or sodium selenite alone (42.87%). MT+Se treatment significantly reduced gray mold incidence in strawberry fruits to <15% at 96 h, versus >75% in controls, while maintaining higher soluble sugar (13.25 vs. 7.01 mg/g) and protein (0.286 vs. 0.186 mg/g) contents. Moreover, MT+Se attenuated oxidative damage by lowering malondialdehyde (MDA) levels (7.47 vs. 11.63 nmol/g FW) and enhancing antioxidant enzyme activities (e.g., POD: 12.918 vs. 8.411 U/g FW). Integrated transcriptomic-metabolomic analyses revealed that MT+Se upregulated antioxidant enzyme genes (SOD, CAT, POD, and APX), resistance-related genes, and transcription factors, while enhancing flavonoid and phenylpropanoid biosynthesis and promoting secondary metabolite accumulation (e.g., epicatechin, naringenin chalcone). Overall, combined MT+Se treatment enhanced strawberry resistance to B. cinerea by boosting antioxidant defense and resistance pathways, offering an eco-friendly strategy for postharvest disease control.