高温处理防治黄瓜霜霉病的生理生化机制

Physiological and Biochemical Mechanism of Prevention for Cucumber Downy Mildew by High Temperature Treatment

以黄瓜感病品种‘长春密刺’为试材,通过室内盆栽试验研究高温对已感染霜霉病菌的黄瓜幼苗生理生化特征的影响.结果显示:(1)在黄瓜幼苗接种霜霉菌后8h,用45℃高温处理90min防治效果最明显.(2)与只接种霜霉病菌的黄瓜幼苗相比,接种霜霉菌后进行高温处理可显著提高叶片叶绿素含量,降低丙二醛含量;与对照相比,接种霜霉菌后进行高温处理可显著提高叶片几丁质酶活性,Western blotting验证了几丁质酶的活性变化.(3)SDS-PAGE结果表明,霜霉菌侵染可诱导一种28kD蛋白表达,高温处理后28kD蛋白的表达量降低.研究结果表明高温处理可能在杀死病原菌的同时,还诱导黄瓜幼苗对霜霉病产生了部分抗性.

The physiological and biochemical mechanism of prevention for cucumber downy mildew by high temperature treatment were studied using cucumber susceptible variety ＇ Changchun mici＇. Cucumber seed- lings were potted in greenhouse. （1）The best effect of prevention reached after seedlings inoculated with Pseudoperonospora cubensis 8 h and then treated for 90 min at 45℃. （2）Compared with seedlings inocula- ted with P. cubensis, chlorophyll contents significantly increased and MDA content significantly decreased by high temperature treatment after inoculation. Compared with control, the activity of chitinase signifi- cantly increased by high temperature treatment after inoculation,and changes in chitinase activity was fur- ther proved by western blotting. （3）A 28 kD protein was induced after inoculation,and then decreased its expression by high temperature treatment. This indicated that high temperature treatment not only could kill much pathogens but also induce resistance against downy mildew.