茉莉酸甲酯诱导辣椒抗青枯病与活性氧代谢的关系

为探究茉莉酸甲酯(Methyl Jasmonate,Me JA)诱导辣椒抗青枯病效应与活性氧代谢相关酶的关系,以辣椒易感青枯病品种‘粤红1号’和抗青枯病品种‘辛香8号’幼苗为试验材料,在0.1mmol·L-1 Me JA喷雾处理后12、24、48、72和96 h接种青枯劳尔氏菌(Ralstonia solanacearum),对其进行青枯病病情指数与活性氧代谢相关酶——超氧化酶歧化酶(Superoxide Dismutase,SOD)、过氧化氢酶(Catalase,CAT)、过氧化物酶(Peroxidase,POD)和抗坏血酸过氧化物酶(Ascorbate Peroxidase,APX)活性以及丙二醛(Malondialdehyde,MDA)含量测定及相互关系的分析。结果表明:‘粤红1号’和‘辛香8号’的病情指数随喷Me JA处理时间的推移表现为先降后升,但都低于对照;而诱导效果则相反,Me JA处理对两个辣椒品种幼苗抗性的最适诱导时间均为接种前48 h。接种后0~96 h,Me JA喷雾处理的辣椒幼苗叶片SOD、CAT、POD和APX酶活性均显示先升后降的趋势,且明显高于对照,接种后24~48 h达到最高,而MDA含量则明显低于对照。因此,Me JA可诱导辣椒幼苗抗青枯病,其实现途径可能与提高活性氧代谢相关酶活性和缓解膜脂过氧化有关。

Involvement of Induced Resistance by Methyl Jasmonate to Bacterial Wilt and Reactive Oxygen Species Metabolism in Pepper Seedlings

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.