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樟树内生枯草芽胞杆菌EBS05是一株对多种植物病原菌具有较强拮抗活性,并能诱导烟草系统抗性的生防菌株。本文以缺失Surfactin A合成相关基因的突变菌株EBS05T为材料,研究了内生细菌EBS05对烟草诱导系统抗性的激发子及其信号转导途径。结果表明,菌株EBS05产生的Surfactin A是诱导烟草对TMV系统抗性的有效激发子;Surfactin A诱导处理后,SA信号转导途径下游的关键调节基因NPR1首先被激活,并持续超量表达,进而触发PR1b和PR1a基因持续超量表达,表明Surfactin A诱导烟草对TMV的系统抗性是通过激活SA信号转导途径实现的。同时,Surfactin A诱导处理后24~72 h,JA/ET信号转导途径调节基因PDF1.2被激活,且超量表达,表明在Surfactin A诱导烟草对TM V系统抗性的信号转导过程中,可能存在SA信号途径和JA/ET信号途径的交叉协同作用。
Camphor tree endophytic Bacillus subtilis EBS05 is a biocontrol strain that has strong antagonistic activity against a variety of plant pathogens and can induce tobacco system resistance. In this study, a mutant strain EBS05T lacking the gene for the synthesis of Surfactin A was used as material to study the elicitors and signal transduction pathways of endophytic bacteria EBS05 against tobacco-induced system. The results showed that Surfactin A produced by strain EBS05 was an effective elicitor for inducing tobacco resistance to TMV system. After Surfactin A induction, NPR1, a key regulatory gene downstream of SA signal transduction pathway, was activated first and then overexpressed continuously The sustained overexpression of PR1b and PR1a genes triggered by Surfactin A indicated that systemic resistance of tobacco to TMV was mediated through the activation of SA signal transduction pathway. Meanwhile, 24-72 h after Surfactin A induction, PDF1.2, a regulator of JA / ET signal transduction pathway, was activated and overexpressed, indicating that during the signal transduction of Surfactin A-induced resistance to TM V system in tobacco , There may be a cross-synergism between the SA signaling pathway and the JA / ET signaling pathway.