Abstract: The disease-resistant effect of H2O2 on post-harvest tomato fruits infected with Botryis cinerea was investigated. Freshly harvested tomato fruits were treated with 10 mmol/L H2O2. One day later, the treated fruits were subjected to establish wound models including mechanical wound and inoculation of Botryis cinerea. The wounded fruits were divided into three groups with mechanically wounded fruits as the control group, the Botryis cinerea-inoculated fruits as the inoc group, and H2O2-pretreated fruits coupled with Botryis cinerea-inoculated fruits as the inoc + H2O2 group. All fruits were stored the environment with temperature of (25 ± 1) ℃ and RH of 80%–85% for 4 days. The results showed that inoc treatment could significantly improve the incidence and lesion area of tomato fruits compared with the control group. After inoculation for 3 days, inoc + H2O2 treatment could reduce disease incidence by 35.5% and lesion area by 29.7% compared with the inoc treatment. In addition, inoc + H2O2 treatment could significantly improve the activities of disease defenserelated enzymes such as PAL and PPO during 1–2 days, GLU and CHI during 1–4 days and induce gene expression level of disease-related protein PR-1. Meanwhile, inoc + H2O2 treatment could significantly improve the relative expression level of NADPH oxidase within 1 day, thereby increasing internal H2O2 content as a signal molecule could induce the disease resistance in tomato fruits. In a word, H2O2 can improve the disease resistance of tomato fruits infected with Botryis cinerea.

Key words: tomato fruit, hydrogen peroxide, Botryis cinerea, induced disease resistance