Volatile Organic Compounds of Clavispora lusitaniae M61 Restrain Tomato Postharvest Botrytis cinerea

Postharvest fruit losses caused by Botrytis cinerea are among the key constraints limiting the development of the tomato industry. Beneficial microorganisms, particularly biocontrol yeasts, play a significant role in the biocontrol of postharvest B. cinerea. Here, a biocontrol yeast strain M61 capable of effectively suppressing postharvest gray mold on tomato fruits was obtained and identified as Clavispora lusitaniae. The volatile organic compounds (VOCs) produced by M61 exhibited significant inhibitory effects against B. cinerea. Simultaneous fumigation with M61 VOCs and pathogen inoculation markedly reduced both disease severity and lesion diameter in tomato fruits; moreover, tomato fruits pre-fumigated with M61 VOCs for 3 days exhibited significantly reduced lesion diameter and disease severity at 5 days post-inoculation with B. cinerea. M61 VOCs also significantly increased phenolic and flavonoid contents as well as transcript levels of genes in the phenylpropanoid metabolic pathway SlPAL and SlF3H. However, M61 VOCs showed no significant effects on tomato fruits in terms of weight loss rate, total soluble solids (TSS), and titratable acidity (TA). Collectively, M61 VOCs inhibited B.cinerea and consequently alleviated gray mold disease severity in tomato fruits for postharvest biocontrol.