摘 要 ：以对霜霉病不同抗性的葡萄品种左优红和霞多丽为材料,利用分子生物学和植物生理学试验手段,结合药理学试验,探讨葡萄在应答霜霉病过程中葡萄多磷酸肌醇激酶基因(VvIPK2)和H2O2的作用机制。接种霜霉病菌后15 h葡萄叶片VvIPK2表达量是正常水平的12倍,接种后3 h H2O2含量达最大值,同时苯丙氨酸解氨酶和几丁质酶活性升高;多磷酸肌醇激酶(IPK2)抑制剂、外源H2O2及H2O2清除剂均能改变霜霉病菌所引起的抗性葡萄品种左优红叶片PAL和几丁质酶活性的变化,同时可以影响不同抗性品种叶片的感病情况;IPK2抑制剂对葡萄霜霉病菌引起的H2O2水平变化没有影响;清除H2O2可减弱葡萄霜霉病菌对VvIPK2表达量的诱导效应。研究表明H2O2位于IPK2的上游,通过调控PAL和几丁质酶活性参与葡萄应答霜霉病过程。
Abstract:Two grapevine cultivars with different resistance to lasmopara viticola-Zuoyouhong, Chardonnay were taken as materials in this study. Through molecular biology, plant physiology and pharmacology experiment approaches, the roles of inositol polyphosphate kinase (VvIPK2 ) and hydrogen peroxide (H2O2) after inoculating P.viticola were studied. The results showed that the expression pattern of VvIPK2 was enhanced to 12 times at 15 hours, the level of H2O2 reaches to maximum value at 3 hours and the activity of PAL and chitinase increased in the leaves after being inoculated; inositol polyphosphate kinase (IPK2) inhibitor, H2O2 scavenger or exogenous H2O2 were able to change the activity of PAL and chitinase and the infective rate of downy mildew in leaves of resistant cultivar-Zuoyouhong infected by P.viticola. At the same time IPK2 inhibitor failed to induce the change of H2O2 induced by P.viticola. However, the expression pattern of VvIPK2 was weakened when H2O2 was scavenged. It was concluded that H2O2 regulated the expression pattern of VvIPK2, then relative enzymes activity so as to enhance the resistance of grapevine against downy mildew.