Abstract: The effect of β-aminobutyric acid (BABA) treatment at different concentrations ranging from 1?500 mmol/ L on the induction of disease resistance in postharvest grape berries and the resistance responses were investigated in the present study. The results showed that BABA treatment could effectively induce disease resistance against Botrytis cinerea infection in grape berries during storage at 20 ℃. Both mock-inoculated and B. cinerea-inoculated grape berries treated with 100 or 500 mmol/L BABA exhibited typical resistance responses, namely H2O2 burst, enhanced expression of defenserelated genes including VvNPR1.1, VvChit4 and VvPR2, and increased activities of chitinase and β-1,3-glucanase as well as the accumulation of stilbene phytoalexins such as trans-resveratrol and its oligomer ε-viniferin. BABA at a concentration of 10 mmol/L had no effect on inducing disease resistance in grape berries directly. However, in grape berries pretreated with 10 mmol/L BABA and then inoculated with B. cinerea, H2O2 production, the transcription levels of pathogenesis-related genes and the contents of phytoalexins significantly increased among all treatments. Meanwhile, 10 mmol/L BABA-treated grape berries maintained higher contents of soluble sugars and higher sweetness index when compared with those treated with BABA at 100 and 500 mmol/L. These results implied that high concentration of BABA (100 and 500 mmol/L) could directly activate defense responses, while low concentration of BABA (10 mmol/L) could trigger a priming defense to prevent substrate overconsumption and maintain fruit quality.

Key words: grape, β-aminobutyric acid, induced resistance, mode, quality