The Antifungal Efficacy of Flavonoids from Sedum aizoon L. on Grapes

The occurrence of gray mold is the main cause of rot and spoilage in grapes, and Botrytis cinerea is the main causative agent of gray mold. The aim of this study is to clarify the inhibitory effect of flavonoids from Sedum aizoon L. (FSAL) on gray mold of grapes and to provide some basis for the development of new natural plant-derived antifungal agents. The effect of FSAL on the disease resistance of grapes was investigated by measuring the disease incidence and lesion diameter. The effect of FSAL on fruit quality was studied by measuring pondus hydrogenii (pH), total soluble solid (TSS), ascorbic acid (AA) and soluble sugar content. The activities of catalase (CAT), peroxidase (POD), phenylalanine ammonia lyase (PAL), and superoxide dismutase (SOD) were used to explore the effect of FSAL on the antioxidant capacities in grapes. The effects of FSAL on the ethylene synthesis in mitogen-activated protein kinase (MAPK) signaling pathway in grapes were investigated by measuring the levels of reactive oxygen species (ROS) and the relative expression of VvACS1 , VvACO1 , VvACO2 , and VvACO3 genes. The results showed that FSAL treatment reduced disease incidence and lesion diameter, increased AA content in fruit and thus maintained fruit quality. FSAL treatment significantly increased CAT, POD, PAL, and SOD activities in fruit, and reduced the relative expression of the genes. In conclusion, FSAL has a certain inhibitory effect on gray mold while not affecting grape quality, and delays the ripening and aging of fruit.