Biocontrol Potential of a Mango-Derived Weissella paramesenteroides and Its Application in Managing Strawberry Postharvest Disease

Postharvest fungal diseases are a major cause of fruit spoilage and economic losses, particularly in perishable commodities like strawberries. In this study, a plant-derived Weissella paramesenteroides strain R2 was isolated from the mango fruit surface and evaluated for its antifungal potential. Dual-culture assays revealed the strong inhibitory activity of strain R2 against key postharvest pathogens, including Botrytis cinerea, Colletotrichum gloeosporioides, and Fusarium oxysporum. Notably, cell-free fermentation broth exhibited no antifungal activity, whereas the volatile organic compounds (VOCs) produced by R2 significantly suppressed fungal growth in sealed plate assays. GC-MS analysis identified 84 VOCs, with pyrazines as the dominant group. Three major compounds, 2,5-dimethylpyrazine, 2,4-di-tert-butylphenol, and 2-furanmethanol, were validated for their antifungal activity. The application of R2 VOCs in strawberry preservation significantly reduced disease incidence and severity during storage. These findings highlight W. paramesenteroides R2 as a promising, food-safe biocontrol agent for postharvest disease management via VOC-mediated mechanisms.