2-Methylbutyric acid functions as a potential antifungal fumigant by inhibiting Botrytis cinerea and inducing resistance to gray mold in cherry tomatoes

Botrytis cinerea causes gray mold disease on postharvest fruit, resulting in serious economic losses. Fumigation with natural volatile organic compounds can replace artificially synthesized fungicides to control postharvest fungal decay of agricultural products. The antifungal effects and potential mechanisms of microbial volatile compound 2-methylbutyric acid (2-MBA) against B. cinerea were investigated in this study. Results showed that 2-MBA inhibited mycelial growth and spores germination, altered mycelial morphology and reduced metabolic vitality of B. cinerea . Moreover, 2-MBA induced oxidative damage by stimulating ROS accumulation, increasing malondialdehyde levels, and decreasing the ratio of reduced/oxidized glutathione. Further studies indicated that 2-MBA reduced mitochondrial membrane potential, interfered TCA cycle by decreasing succinate dehydrogenase activity and ATP content, ultimately leading to decreased mitochondrial activity. In addition, key genes involved in botrydial biosynthesis and mycelial growth were down-regulated. 2-MBA controlled postharvest gray mold by inducing resistance to B. cinerea in cherry tomatoes. Taken together, 2-MBA is an effective and promising fumigant to control gray mold caused by B. cinerea .