我国主要生态区域绿豆慢生根瘤菌的遗传多样性和系统发育研究

Studies on genetic diversity and phylogeny of slow_growing rhizobia isolated from Vigna radiata at main ecotypes of China

利用16SrRNAPCR-RFLP、16SrRNA序列分析以及16S-23SrRNAIGS(IntergeneticSpacer)PCR-RFLP技术对分离自中国主要生态区域的44株慢生型绿豆根瘤菌和5株参比菌株进行了遗传多样性和系统发育研究。16SrRNAPCR-RFLP分析表明:在76%的相似水平上,所有供试菌株可分为三大类群:群I由LYG1等13株慢生根瘤菌组成,该群在系统发育上与B.japonicum和B.liaoningense的参比菌株存在一定的差异;群Ⅱ由XJ1等21株供试菌株、B.japonicum和B.liaoningense的代表菌株组成;群Ⅲ由10株来自广东和广西的菌株和B.elkanii的代表菌株组成。16S-23SrRNAIGSPCR-RFLP分析将供试菌株分为A、B两大群。群A由34株供试菌株、B.japonicum和B.liaoningense的代表菌株组成。在85%的相似性水平上,可再分为AⅠ、AⅡ和AⅢ3个亚群。群B由10株分离自广西和广东的菌株和B.elkanii的代表菌株组成。在85%的相似性水平上,可再分为BI和BⅡ两亚群,表现出一定的多样性。与16SrRNAPCR-RFLP相比,16S-23SrRNAIGSPCR-RFLP具有更高的解析度,供试菌株表现出更加丰富的遗传多样性。分离自中国新疆、广东和广西等地的菌株在分群上具有较为明显的地域特征。

Studies on genetic diversity and phylogeny of slow-growing rhizobia isolated from Vigna radiata at main ecotypes of China were conducted by using 16S rRNA gene PCR-RFLP, 16S rRNA gene sequencing and 16S-23S rRNA IGS PCR-RFLP assays. Results of 16S rRNA gene PCR RFLP analysis reveal that all the strains tested are clustered into three groups at the similarity of 76%. Group Ⅰ contains 13 slow-growing rhizobia tested including LYG1 ; Group Ⅱ consists of 21 strains tested and the type strains of B. japonicum and B. liaoningense, and 10 tested strains isolated from Guangdong, Guangxi and the type strain of B. elkanii, compose Group m The results of 16S-23S rRNA IGS PCR-RFLP show that strains tested could be divided into A and B groups, which could be correspondently subdivided into A Ⅰ , A Ⅱ , AⅢ, BⅠ and B Ⅱ subgroups at the similarity of 85 % . Compared with 16S rRNA PCR-RFLP, IGS RFLP assay show higher resolution, strains and reference strains tested can be divided into 21 IGS RFLP patterns. The strains isolated from Xinjiang, Guangdong and Guangxi regions show obvious geographical effect on genetic diversity.