超慢生大豆根瘤菌DNA G+C含量和DNA同源性测定  

ETERMINATION OF DNA G+C mol% AND DNA HOMOLOGY BETWEEN EXTRA-SLOW-GROWING SOYBEAN RHIZOBIA AND OTHER RHIZOBIA

作　　者：李俊[1] 葛诚[1] 徐玲玫[1] 樊蕙[1] 崔阵 

机构地区：[1]中国农业科学院土壤肥料研究所,北京100081

出　　处：《微生物学报》1994年第2期143-147,共5页Acta Microbiologica Sinica

基　　金：国家自然科学基金资助项目

摘　　要：用热变性温度法和液相复性速率法分别测定了超慢生大豆根瘤菌(ESG,extra-slow-growing soybean rhizobia)DNA G+C mol%及与其它根瘤菌间的DNA同源性.结果表明,ESG的DNA G+C mol含量在59.2—63.5%之间,且不同地区不同血清型的ESG代表菌株DNA同源率在70%以上,说明它们是遗传型一致的类群.ESG与在大豆上结瘤的快生大豆根瘤菌(Rhizobium fredii USDA205)同源率为14.8%,与慢生大豆根瘤菌(Bradyrhizobiumjaponicum)三个DNA同源组的同源率分别为20.5%,30.0%,19.4%.测定结果还表明,ESG与其它根瘤菌遗传学的亲缘关系也很远.The DNA G+C mol% for extra-slow-growing soybean rhizobia (ESG) and DNA homology for ESG strains and other rhizobia were carried out by thermal denatu-ration temperature (Tm) and reassociation rate of DNA, respectively. The results showed that : (1) DNA G+C mol% of the sixteen ESG strains isolated from root nodules of Glycine max and G. soja was 59. 2-63. 5% and the DNA homology among five representative strains of ESG was greater then 7 0 % ( range ,72. 1 to 93. 4%), which indicated that these strains were in one genetic group. (2) DNAs from 5 ESG representative strains had very low mean homology (range,3. 8 to 30. 0%) with 16 other reference rhizobial strains. The results indicated that ESG was genetically distinct from other recognized rhizobia.

关 键 词：超慢生 大豆根瘤菌 DNA 同源性 

分 类 号：Q939.114[生物学—微生物学]