Abstract
BACKGROUND: Botrytis cinerea, a notorious fungal pathogen, is responsible for causing grey mold in fruits and vegetables during the postharvest period. The use of environmentally friendly natural compounds presents a viable alternative to synthetic fungicides for managing postharvest diseases. 3-methyl pentanoic acid (3MP), a short-chain fatty acid widely employed as a flavoring agent and in agrochemicals, has not been explored for its potential in controlling postharvest diseases or its underlying mechanisms of action. RESULTS: This study aimed to evaluate the antifungal activity and elucidate the potential mechanisms of action of 3MP against B. cinerea. Specifically, the effects of 3MP on mycelial growth, spore germination, disease development in tomatoes and strawberries fruit, cell viability, cell membrane integrity, and the expression of key genes (Chs1, Bmp1, Bmp3, and Sak1) associated with cell wall integrity (CWI) and mitogen-activated protein kinase (MAPK) signaling in B. cinerea were investigated. Results showed that mycelial growth, sporulation, spore germination, germ tube elongation, of B. cinerea were significantly suppressed by 3MP in a dose dependent manner. In vivo tests demonstrated that 3MP effectively controlled postharvest grey mold caused by B. cinerea on tomatoes and strawberries at concentrations of 12 μL/L. Fluorescein diacetate (FDA) and propidium iodide (PI) staining assays indicated that 3MP disrupted membrane integrity and impaired cell viability in B. cinerea. Additionally, the expression levels of CWI and MAPK-related genes Chs1, Bmp1, Bmp3 and Sak1 were significantly altered following 3MP treatment. CONCLUSION: 3MP represents a promising natural alternative to commercial fungicides or a lead compound for developing new biofungicide to control grey mold disease during the postharvest period. These results provide a theoretical basis for elucidating the underlying antifungal mechanism of 3MP against B. cinerea.