Mechanistic investigation of sucrose monostearate-mediated antifungal effects against Penicillium oxalicum

Penicillium oxalicum is a major postharvest pathogen of kiwifruit, causing substantial economic losses. This study investigated the antifungal activity and mechanism of sucrose monostearate (SMS) against P. oxalicum . The minimum inhibitory concentration (MIC) of SMS was determined to be 1.25 g L − 1 , which significantly inhibited spore germination by 88.28% and reduced mycelial growth by 65.94% ( p  < 0.05). Mechanistically, SMS at 1.25 g L − 1 induced intracellular ROS accumulation by 1.7-fold, suppressed catalase (CAT) and peroxidase (POD) activities by 54% and 60%, and increased malondialdehyde (MDA) content by 2.5-fold, confirming severe membrane lipid peroxidation and content leakage. Scanning electron microscopy revealed marked hyphal deformation, and in vivo assays showed that SMS reduced kiwifruit lesion diameter by 83.7% compared to controls. These findings demonstrate that SMS, as a single-ester antifungal agent, disrupts fungal membrane integrity and exhibits strong potential for postharvest disease control.