NO和钙信使系统在草酸诱导黄瓜叶片抗霜霉病中的作用

Role of Nitric Oxide and Calcium Signaling in Oxalate-induced Resistance of Cucumber Leaves to Pseudoperonospora cubensis

通过草酸及其与不同抑制剂亚甲基蓝、EGTA、氯丙嗪和Li+组合处理黄瓜叶片,研究了草酸与抑制剂不同处理组合方式对黄瓜叶片POD活性和叶片病情指数的影响,探讨NO、钙信使系统在草酸诱导叶片抗霜霉病中的作用.结果显示,10～70mmol/L草酸均能不同程度诱导黄瓜叶片POD活性的升高,提高叶片对黄瓜霜霉病的抗病性,降低叶片病情指数,并以30mmol/L效果最好.4种抑制剂分别与30mmol/L草酸同时或先于草酸处理,或草酸处理后一定时间再用抑制剂处理,均明显抑制黄瓜叶片POD活性的升高及病情指数的降低.研究表明,NO、Ca2+、钙调素(CaM)和磷酸肌醇均可能参与了草酸诱导黄瓜霜霉病抗性的信号转导过程.

The effect of oxalate, MB, EGTA, chlorpromazine （CPZ） and Li＋ on the POD activity and the dis- ease index of Pseudoperonospora cubensis leaves was investigated,with which treated the leaves, and the role of nitric oxide and calcium signaling in the resistance induced by oxalate in cucumber leaves was stud- ied. The results showed that oxalate could increase POD activity in different degree with the concentration from 10 mmol/L to 70 mmol/I.,and improve the resistance to P. cubensis,and reduce the disease index. The treatment with 30 mmol/L was the best. Four inhibitors could inhibit POD activity induced by oxalate and increase the disease index when they were applied at the same time as oxalate or before oxalate treatment, or after the oxalate treatment of 30 mmol/L. These results suggested that NO,Ca2＋ ,calmodulin （CAM） and inositol-l,4,5-trisphosphate （IP3） might be involved in the signal transduction by which oxalate in- duced the systemic resistance to P. cubensis.