内生细菌EBS05对番茄植物的促生和诱导抗病性信号转导途径的研究

Study on growth promotion and signaling pathway of induced systemic resistance elicitation mediated by endophytic bacteria strain EBS05 in tomato plant

以番茄品种江蔬14号为试验材料,研究了内生细菌EBS05对番茄的促生作用及其对番茄抗番茄黄化曲叶病毒(TYLCV)的诱导作用。研究结果表明,EBS05对番茄植株具有明显的促生作用,能诱导番茄体内细胞生长相关扩张蛋白基因LeEXP2、LeEXP5和LeEXP18的增量表达。EBS05菌悬液诱导处理后接种TYLCV,SA信号转导途径下游关键基因NPR1和PR1在第1天均被激活,且于诱导处理后3~5 d增量表达,至第7天达到最高峰值,分别比对照番茄植株增加了16倍和13倍。由此推测,内生细菌EBS05诱导番茄对TYLCV的系统抗性是通过SA信号转导途径实现的。同时,接种后5 d,JA信号转导途径标记基因Coi1被激活,且增量表达,表明在内生细菌EBS05诱导番茄对TYLCV系统抗性信号转导途径过程中,可能存在SA信号途径和JA信号途径的交叉协同作用。

The plant growth promotion and signaling pathway of induced systemic resistance(ISR)elicitation mediated by endophytic bacteria strain EBS05 in tomato plant against tomato yellow leaf curl virus(TYLCV)were investigated using the tomato variety Jiangsu 14 as a test material.The results showed that strain EBS05 could significantly promote the growth of tomato plants by inducing the over-expression of LeEXP 2,LeEXP5 and LeEXP18 genes with related to cell growth in tomato plant.The key regulatory genes NPR 1 and PR1 in salicylic acid(SA)-signaling transduction pathway in test plants pretreated by strain EBS05 suspension were activated at the first day after inoculated with TYLCV and over-expressed from the third day to the fifth day,and reached maximum expression at the seventh day.The expression levels increased sixteen fold and thirteen fold compared with those of genes in control plants.It suggested that ISR mediated by strain EBS05 in tomato plant against TYLCV depended on SA-signaling transduction pathway.Meanwhile,the gene Coi 1,as a key regulatory gene in jasmonic acid(JA)-signaling transduction pathway,was elicited and over-expressed at the fifth day after inoculated with TYLCV.It suggested that cross-talk between SA-and JA-dependent signaling transduction pathways might be involved in ISR mediated by strain EBS05 in tomato plants defense against TYLCV.