枯草芽孢杆菌OKB105产生的surfactin防治烟草花叶病毒病及其机理研究

本文研究枯草芽孢杆菌产生的脂肽化合物表面活性素surfactin对烟草花叶病毒病的防治效果，并检测烟草防卫相关基因的表达情况以解析抗病机理。利用6 mol/LHCl沉淀枯草芽孢杆菌OKB105的去细胞培养液，通过甲醇抽提，Sephadex LH20层析柱获得脂肽纯化物。经MALDI-TOF-MS和血平板溶血试验检测表明，纯化物中仅含有表面活性素surfactin。将表面活性素配成0.01 g/L溶液，处理烟草并接种TMV。结果表明， surfactin对烟草花叶病毒病有显著的防治效果，病斑抑制率为70.9%。通过Real-time PCR检测烟草的防卫相关基因的表达情况结果发现，烟草SA信号通路的PR1、PR3和PR5，以及ET通路的ETR1表达量显著提高，说明surfactin诱导了烟草依赖于SA和ET信号通路的诱导系统抗性（induced systemic resistance, ISR）反应。

Effect and Mechanism of Controlling TMV Disease on Tobacco by Surfactin Produced by Bacillus subtilis OKB105

In order to interpret resistance mechanism, controlling effect of surfactin against TMV on tobacco and the expression pattern of defense-related genes were investigated. Liquid culture of Bacillus subtilis OKB105 was precipitated by 6 mol/L HCl. The crude extract of lipopeptides was dissolved by methanol and separated by LH20 chromatographic column. The crude extract detected surfactin only by MALDI-TOF-MS and hemolytic activity analysis. Tobacco was infected with TMV after pretreated by 0.01 g/L surfactin, the result showed that surfactin could control TMV efficiently, the controlling effect reached to 70.9%. The expressions of SA-pathway genes PR1, PR3, PR5, and ET-pathway gene ETR1 were obviously increased by real-time PCR test. The results demonstrated that surfactin could elicite ISR (induced systemic resistance) reaction which depend on SA-pathway and ET-pathway.