Combined natamycin and methyl jasmonate treatment improves postharvest quality and resistance to gray mold in cherry tomatoes via dual antifungal and defense-inducing mechanisms

Postharvest cherry tomatoes suffer from severe economic losses due to dehydration, senescence, and gray mold caused by Botrytis cinerea ( B. cinerea ). This study systematically evaluated the preservation efficacy of combined natamycin (NAT) and methyl jasmonate (MeJA) treatment on cherry tomatoes via antifungal assays, physiological index detection, and transcriptome analysis. The results showed that 1.5 mmol/L NAT + MeJA could inhibit the mycelial growth of B. cinerea (81.67%). And it also delayed weight loss (25.7% of the control on day 8), peak respiratory rate (21% decrease on day 6), peak ethylene release (0.4 μL/(kg·h) on day 6), and accumulation of malondialdehyde (MDA) (reaching a peak of 14.8 nmol/g FW on day 4); Simultaneously maintaining firmness, total soluble solids (TSS) etc., while inhibiting polyphenol oxidase (PPO) activity. In addition, it enhanced the activity of superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD), and promoted the accumulation of total phenolic and flavonoid substances. Transcriptome analysis revealed that the combined treatment regulated genes in MAPK signaling, plant-pathogen interaction, and phenylpropanoid biosynthesis pathways to activate host defense. In conclusion, the NAT + MeJA system exerts dual effects of direct antifungal action and resistance induction, serving as a promising green and efficient preservation technology.