Mushroom alcohol treatment inhibited the growth of Alternaria tenuissima and reduced the incidence of postharvest diseases of fresh wolfberry fruit

Abstract

Wolfberry (Lycium barbarum) is an important economic tree species in northwest China. The postharvest decay of fresh wolfberry fruit, caused by infection from Alternaria spp., has become increasingly serious. In this study, the inhibitory mechanism of mushroom alcohol treatment on Alternaria tenuissima was researched using the fumigation method. The results indicated that treatment with mushroom alcohol at a concentration of 0.188 mL/L (50% of maximal effect), effectively inhibited the growth of A. tenuissima mycelium, and reduced biomass and sporulation. Mushroom alcohol treatment increased the activity of superoxide dismutase in A. tenuissima, promoted the accumulation of superoxide anion and hydrogen peroxide in the early stages of culture, inhibited the activity of catalase and polyphenol oxidase, and disturbed the balance of antioxidant metabolism. Furthermore, mushroom alcohol treatment reduced the activity of dehydroascorbate reductase, monodehydroascorbate reductase, and glutathione peroxidase and decreased the amount of antioxidants, resulting in decreased pathogen resistance. The treatment also damaged the cell membrane structure of A. tenuissima, leading to increased relative conductivity, malondialdehyde accumulation, and extensive leakage of nucleic acids and proteins. After the wolfberry was inoculated with the pathogenic fungus, mushroom alcohol treatment significantly reduced wolfberry disease incidence and lesion area. This treatment delayed disease onset and reduced disease severity in harvested wolfberry, suggesting its potential for postharvest fruit preservation.