亚精胺诱导黄瓜幼苗对白粉病抗性的研究

以黄瓜品种‘长春密刺’幼苗为材料,研究了亚精氨(Spd)诱导黄瓜幼苗对白粉病的抗性,并测定Spd处理和白粉菌接种对黄瓜叶片4种防御酶活性及3种防卫基因表达的影响。结果显示:(1)0.2～1.0mmol.L-1 Spd对黄瓜幼苗白粉病抗性均有不同程度的诱抗效果,并以0.8mmol.L-1 Spd处理效果最明显,诱导效率可达55.3%。(2)喷施Spd或接种白粉菌均可提高黄瓜叶片过氧化物酶(POD)、苯丙氨酸解氨酶(PAL)、几丁质酶和β-1,3-葡聚糖酶的活性,且诱导并接种处理的植株叶片上述酶活性均比只诱导不接种处理的上升速度更快;同时,Spd处理和接种白粉菌可以提高植株叶片中POX、PAL、PR-1a基因的表达量。研究表明,Spd处理可以诱导防卫基因表达的增强,提高防御酶活性,显著降低病情指数,增强黄瓜幼苗对白粉病的抗性。

Induction Resistance to Powdery Mildew by Spermidine in Cucumber Seedlings

The effect of spermidine on induced resistance to powdery mildew in Cucumis sativus L.cv.’Changchun mici’ seedlings was conducted,and the activities of 4 defense enzymes and expression of 3 defense gene were tested in cucumber leaves after treated with spermidine and inoculated with powdery mildew.The results showed that:(1)0.2～1.0 mmol·L-1 spermidine expressed different induced effects on cucumber seedlings powdery mildew resistance,and 0.8 mmol·L-1 spermidine had the best effects on cucumber seedlings and the induced efficiency reached to 55.3%.(2)The defense enzymes of cucumber seedlings such as peroxidase(POD),phenylalanine amonnialyase(PAL),chitinase and β-1,3-glucanase activities increased after spermidine inducement or powdery mildew inoculation.The increase of these enzymes activity treated with both spermidine inducement and powdery mildew inoculation were faster than those only treated with inducement.The expression of POX,PAL,PR-1a gene enhanced after spermidine inducement or powdery mildew inoculation.In summary,the results indicate that spermidine enhance the expression of defense genes,increase the activities of defense enzymes,decrease disease index significantly,then increase cucumber resistance to powdery mildew.