黄瓜抗细菌性角斑病诱抗药剂的筛选及抗性机制研究

为筛选诱导黄瓜抗细菌性角斑病(angular leaf spot, ALS)的最佳诱抗药剂，选取11种商品诱抗剂，研究其室内诱导黄瓜抗细菌性角斑病的作用效果。结果显示11种诱抗剂的预处理均能有效提高黄瓜植株的长势，提高黄瓜对细菌性角斑病的抗性，表现为叶片病斑面积显著下降。其中药剂信号施康乐(SK)能有效减小叶片病斑面积，防效最好，而药剂顶花增瓜嫩直长(DH)处理的植株叶片病斑面积最大。为了进一步明确诱抗剂的作用机制，对诱抗剂SK和DH处理后的抗性相关基因SOD、SSU以及PR1-1a的相对表达量进行了初步分析。结果表明，SK和DH处理后3个基因的相对表达量均显著提高，SK处理的相对表达量显著高于DH处理。综上所述，合理施用信号施康乐可以诱导黄瓜幼苗提高对细菌性角斑病的抗性，对于黄瓜细菌性角斑病的早期预防和减少农药使用具有重要意义。

Screening of inducers to bacterial angular leaf spot of cucumber and its resistance mechanism

In order to screen effective inducers to bacterial angular leaf spot (ALS) of cucumber, 11 commercial inducers were selected to investigate the inducing resistance to ALS in cucumber plants. Results showed that commercial inducers treatment improved the resistance of cucumber seedlings to ALS. The growth of plants treated with commercial inducers was improved and the lesion area of cucumber leaves inoculated with Pal was significantly decreased. Among the commercial inducers, signal-shikangle (SK) treatment has the best control effect with the smallest leaf lesion area, and inducer of plants (DH) treatment had relative low control effect. In order to further clarify the mechanism of inducers, the relative expression levels of SOD, SSU and PR1-1a genes which related to resistance were preliminarily analyzed after treatment with SK and DH. The results showed that the relative expression levels of above three genes were significantly increased after treated with SK and DH, and that treated with SK was significantly higher than that treated with DH. In conclusion, reasonable application of SK may induce cucumber seedlings to improve the resistance to ALS, which is of great significance for the early prevention of ALS and the reduction of pesticide application.