Gray mold, caused by Botrytis cinerea, is the primary factor contributing to postharvest losses in table grape fruit. In this study, we have identified amphotericin B (AMB), a natural compound originating from Streptomyces nodosus, as a promising agent in managing postharvest gray mold in table grapes. In vitro experiments demonstrated that 0.2 mg/L AMB achieved an inhibition rate of over 90% against B. cinerea in PDA medium, and in vivo assays on grape berries showed that 200 mg/L AMB treatment could completely suppress the occurrence of gray mold disease. A mechanism analysis found that AMB treatment disrupted the plasma membrane structure, which consequently triggered cellular leakage and induced cell death. Furthermore, AMB application effectively modulated the transcriptional profile of genes related to redox homeostasis, transmembrane transport, and peroxidase functions in B. cinerea, thereby reducing the virulence of the fungus. In addition, AMB treatment had the potential to activate defense mechanisms in table grapes by enhancing the activities of ROS-scavenging enzymes and defense-associated enzymes. Collectively, AMB can be regarded as a natural antifungal agent that effectively combats B. cinerea, thereby extending the postharvest shelf life of table grape fruit.

Anthracnose, caused by Colletotrichum gloeosporioides, is a destructive postharvest disease that substantially reduces the quality and shelf life of apple fruit. Effective and environmentally friendly strategies for controlling this disease remain limited. In this study, we investigated the antifungal activity of benzyl isothiocyanate (BITC), a naturally occurring sulfur-containing volatile organic compound, against C. gloeosporioides and explored its underlying mechanism of action. In vitro assays showed that BITC strongly inhibited fungal growth and development, with mycelial growth completely inhibited at 25 mg/L and spore germination as well as germ tube elongation completely suppressed at 30 mg/L. In vivo, BITC at 150 mg/L effectively suppressed anthracnose lesion expansion on apple fruit. Further mechanistic analyses demonstrated that BITC induced membrane lipid peroxidation, compromised membrane integrity, and caused the leakage of intracellular constituents, thereby markedly reducing spore viability. In addition, RT-qPCR analysis revealed that BITC significantly downregulated the expression of several key pathogenicity-related genes. Collectively, these findings indicate that BITC inhibits C. gloeosporioides by disrupting membrane integrity and suppressing pathogenicity, highlighting its potential as a natural antifungal agent for the management of postharvest apple anthracnose.