Abstract: To explore the relationship between methyl jasmonate（MeJA）-induced resistance to bacterial wilt and enzymes related to reactive oxygen species metabolism in pepper，the susceptible variety‘Yuehong 1’and resistant variety‘Xinxiang 8’were used as the experimental materials in the study. Seedlings were inoculated with Ralstonia solanacearum after 12，24，48，72 and 96 h of spraying treatment with 0.1 mmol ? L-1 MeJA solution，respectively. The indexes of bacterial wilt，the activities of enzymes related to reactive oxygen species（ROS）metabolism including superoxide dismutase（SOD），catalase（CAT），peroxidase（POD）and ascorbate peroxidase（APX），and the contents of malondialdehyde（MDA）were determined. The results showed that the bacterial wilt indexes of‘Yuehong 1’and‘Xinxiang 8’decreased at first and then increased with the times of MeJA treatment increasing from 12 to 96 h，but were always lower than that of the control，while the induced effects were opposite. The optimal treatment time of MeJA-induced resistance to bacterial wilt was 48 h before inoculation. During 0–96 h after inoculation，the SOD，CAT，POD and APX activities of pepper seedlings treated with MeJA were obvious higher than those of the control，and showed a change of increasing gradually and reaching their peaks in 24–48 h after inoculation，and then decreasing，while the MDA contents were always lower than those of the control. These results suggested that MeJA induced resistance to bacterial wilt in pepper seedlings，and the increased activities of enzymes related to reactive oxygen species metabolism and the decreased lipid peroxidation might be involved in this resistance induction.

Key words: pepper, methyl jasmonate, bacterial wilt, induced resistance, enzymes related to reactive oxygen species metabolism