Antifungal effect and control of Alternaria fruit rot in blueberry through ε-polylysine hydrochloride

Blueberry was easily infected by Alternaria sp. during storage time, leading to Alternaria fruit rot (AFR). ε-polylysine hydrochloride (ε-PL), a widely used food additive, was evaluated for its antifungal efficacy at different concentrations and its effects on the quality of blueberries treated with 3 g L^-1 ε-PL. The results revealed that ε-PL effectively inhibited the mycelial growth of Alternaria sp. by destroying its cell membrane structure, resulting in nucleic acid and soluble protein leakage. Furthermore, ε-PL treatment reduced the incidence of AFR in blueberries by 23.7 % at 4 d. It enhanced the disease resistance of blueberries by increasing both the activity and gene expression of β-1,3-glucanase. Additionally, ε-PL elevated the activities and gene expression of antioxidant enzymes, thereby reducing hydrogen peroxide content by 62.77 %. These findings suggested that ε-PL could serve as a novel antifungal agent for managing postharvest AFR in blueberries.