胡萝卜软腐果胶杆菌胡萝卜亚种mreB基因的功能分析  

Functional characterization of mreB gene from Pectobacterium carotovorum subsp. carotovorum

作　　者：邓亚岷[1] 杜硕 王欢[1] 杨钟灵[1] 刘凤权[1] 范加勤[1] 

机构地区：[1]南京农业大学植物保护学院/农作物生物灾害综合治理教育部重点实验室,江苏南京210095

出　　处：《南京农业大学学报》2014年第2期45-52,共8页Journal of Nanjing Agricultural University

基　　金：江苏高校优势学科建设工程资助项目

摘　　要：为了阐明细菌杆状决定蛋白mreB基因对胡萝卜软腐果胶杆菌胡萝卜亚种(Pectobacterium carotovorum subsp.carotovorum,Pcc)生物学特性及致病性的影响,采用同源重组的方法成功构建了该基因的缺失突变株、互补菌株及过表达菌株,并进行了相关表型测定。结果表明:与野生型菌株PccS1相比,缺失突变株ΔmreB菌体形态由杆状变为球形;对黄花马蹄莲和大白菜的致病性显著下降;生长能力也受到一定限制;尽管分泌胞外纤维素酶的能力、抗氧化压力和菌体沉降速率无明显变化,但蛋白酶活性、果胶酶活性、生物膜形成能力、游动性及产生碳青霉烯抗生素的能力均有不同程度的下降。互补菌株的表型得到了部分或全部恢复。qRT-PCR结果也显示:ΔmreB中几种相关致病因子的相对表达量均下调。表明:mreB与胡萝卜软腐果胶杆菌的菌体形态、生长能力和致病能力密切相关。这是首次报道mreB与植物病原菌的致病性相关。To investigate the roles in biologic and pathogenicity characterization of mreB gene in Pectobacterium carotovorum subsp. carotovorum（Pcc） ,we generated a mreB deletion mutant △mreB, the complementary strain △mreB （mreB）and overexpression strain PccS1 （mreB）by biparental mating, and determined the related phenotypes. Compared with wild-type strain PetS1, the cell morphology of △mreB was changed from rod to ball. The pathogenicity of mutants on Zantedeschia elliotiana and Brassica pekinensis were attenuated. Growth was also subject to certain restrictions in △mreB. No apparent alterations in cellulose activity, ability of anti-oxidative stress and cell sedimentation rate were found, but the activities of protease,pectinase,biofilm formation, motility and production of car- bapenem antibiotics were all reduced obviously. And the complementary strain restored the phenotypes partially or completely. The results of qRT-PCR also showed significant decrease in relative expression of related pathogenic factors in △mreB. In conclusion,mreB gene plays a crucial role in cell morphology, growth and pathogenesis of P. carotovorum subsp, carotovorum. To our knowledge, this is the first report about functions of the mreB gene in the pathogenicity of phytopathogenic bacterium.

关 键 词：胡萝卜软腐果胶杆菌胡萝卜亚种 mreB基因 细胞形态 致病性 

分 类 号：Q933[生物学—微生物学]