Abstract: The inhibitory effects of β-aminobutyric acid (BABA) on gray mold decay caused by Botrytis cinerea in harvested strawberry fruits stored at (5 ± 1) ℃ and the possible mechanisms were investigated. The strawberry fruits were pretreated with 20 mmol/L BABA, inoculated with the spores of Botrytis cinerea, and then stored at (5 ± 1) ℃ for 12 days. The results showed that the fruits treated with BABA had significantly lower disease incidence and smaller lesion diameters than the control fruits. The fruits treated with BABA showed 9.2% higher activity of chitinase (CHI) and 54.9% higher activity of β-1,3-glucanase (GLU) than the control fruits at the end of storage. BABA-treated fruits showed 29.3% lower activity of polygalacturonase (PG) and 24.4% lower activity of cellulose (Cel) than the control fruits. BABA treatment upregulated the expression of FaCHI and FaGLU and downregulated the expression of FaPG and FaCel. Moreover, BABA damaged the plasma membrane integrity of B. cinerea spores and caused the leakage of protein and sugar from the pathogen mycelia in vitro. The results indicated that BABA could effectively inhibit gray mold decay in strawberry fruits, which may be related to increased defense-related enzyme activities in fruits, suppressed PG and Cel activities and direct fungitoxic property against the pathogen.

Key words: strawberry, β-aminobutyric acid, Botrytis cinerea, induced resistance, gene expression, plasma membrane integrity