十字花科黑腐病菌中一个受HpaS调控的基因的功能分析  

Function Analysis of a Gene Isolated from Xanthomonas campestris pv.campestris Regulated by HpaS

作　　者：万惠芳 姚家丽 苏辉昭[1] 李瑞芳[1] 李磊[1] 陆光涛[1,2] 

机构地区：[1]广西大学生命科学与技术学院,南宁530005 [2]亚热带农业生物资源保护与利用国家重点实验室,南宁530005

出　　处：《基因组学与应用生物学》2016年第2期342-349,共8页Genomics and Applied Biology

基　　金：国家自然科学基金面上项目(31371263)资助

摘　　要：十字花科黑腐病菌(Xcc 8004)中一对双组份系统hpa S/hpa R2在致病过程中有重要作用,以前的研究发现,XC2388的表达可能受XC3669/XC3670的调控。为分析XC2388的功能,本试验采用p K18mob Sac B介导的同源双交换的方法构建缺失突变体,对新获得的缺失突变体DM2388的分析发现,XC2388突变后,病原菌对寄主萝卜叶的致病力与野生型相比降低80%,采用PCR扩增XC2388完整的ORF,将新获得的1 349 bp的DNA片段克隆在p LAFR3质粒上,将新获得的重组质粒导入DM2388,发现互补菌株CDM2388的致病力可以恢复至野生型的60%,表明XC2388与致病性相关。以MMX培养基为介质绘制生长曲线,经分析发现突变体的生长严重受阻,在培养基中加入Thr后可以恢复生长,表明DM2388可能是与Thr合成相关的营养缺陷性菌株。A two-component system hpaS/hpaR2 ofXanthomonas campestris pv. campestris （Xcc） 8004 plays important roles in regulating bacterial diverse biological processes. Previous studies showed that the expression of XC2388 may be regulated by XC3669/XC3670. To investigate its function, the deletion mutant of XC2388 was constructed by using suicide plasmid pK18mob SacB through homologous double-crossover. Analysis revealed that virulence of the deletion mutant in the host plant decreased 80% compared to the wild-type strain. DNA fragment with 1 349 bp length located on open reading frame ofXC2388 was amplified and inserted into pLAFR3 plasmid and the formed recombinant plasmid was introduced into DM2388. It was revealed that the complementation strain CDM2388 restored its pathogenicity to 60% compared with the wild-type level. It indicated that the XC2388 gene had some effects on virulence. The growth analysis on the MMX medium revealed that the mutant growth was blocked, but it restored its growth when added threonine in the MMX medium. It revealed that DM2388 may be an auxotrophic strain which is relation to threonine synthesis.

关 键 词：十字花科黑腐病菌 致病力 营养缺陷型 

分 类 号：S432.42[农业科学—植物病理学]