野油菜黄单胞菌两个rpoN基因的突变和功能分析  

Functional characterization of two rpoN genes in Xanthomonas campestris pv.campestris

作　　者：李恒聪[1] 蒋瑞萍[1] 姜伯乐[1] 唐东阶[1] 唐纪良[1] 

机构地区：[1]广西大学生命科学与技术学院

出　　处：《广西农业生物科学》2006年第1期30-37,共8页Journal of Guangxi Agricultural and Biological Science

基　　金：广西自然科学基金(桂科自0229002);教育部科学技术研究重点项目(地方03100)

摘　　要：细菌的σ54(R poN)是一类可选择性识别启动子序列的σ因子,主要参与环境适应、细胞生理过程等,如氮代谢、鞭毛和菌毛的生物合成。在一些病原菌中,σ54也与致病性密切有关。为了明确σ54在野油菜黄单胞菌野油菜致病变种(X cc)中是否参与致病过程,用同源单交换定点突变方法,将X cc 8004中的两个σ54编码基因rp oN 1(XC 1256)和rp oN 2(XC 2168)做单突变及双突变。突变体表型分析结果表明,单个和同时突变rp oN 1和rp oN 2基因均不影响野油菜黄单胞菌的正常生长,对胞外多糖(EPS)产生、胞外酶的合成也无明显影响。植株致病性检测结果表明,rp oN 1和rp oN 2基因的单突变或双突变体的致病力与野生型菌株没有显著差异,表明野油菜黄单胞菌野油菜致病变种的致病过程不需要σ54因子参与。σ^54 （RpoN）, an alternative promoter-recognizing a factor, was involved in expression of specialized metabolic functions, nitrogen metabolism and biosynthesis of flagellar and pilus. Involvement of σ^54 in virulence of Pseudomonas had also been reported. To determine whether σ^54 was required for virulence of Xanthornonas carnpestris pv. carnpestris （Xcc）, by using site-directed homologous singlerexchange mutagenesis method, author constructed single and double mutant of rpoN1 （XC1256） and rpoN2 （XC2168） in Xcc. Effects of mutation in two genes on cell growth, EPS production, extracellular enzymes activity, and virulence of Xcc were tested. Results showed that no significant influences on these phenotypes were observed by single or double mutation of rpoN1 and rpoN2. σ^54 was not required for virulence of Xanthomonas campestris pv. campestris （Xcc） in our plant assays condition.

关 键 词：Xcc RPON 双突变 致病性 

分 类 号：S432.42[农业科学—植物病理学]