我国亚热带地区快生型大豆根瘤菌遗传多样性研究

摘要

Genetic diversity of 31 isolates from effective nodules of soybean in different geographical regions of China was studied using 16S rDNA gene RELP patterns, 16S rDNA gene sequencing, 16S— 23S rDN A IGS region RE LP patterns and 16S — 23S rDN A IGS sequencing assays. The isolates were clustered into one genospecies with Sinorhizobium fredii USDA205 on the basis of their 16S rDNA gene PCR - RFLP patterns. 16S rDNA gene sequence of strains indicated that the isolates were very closely related (identities higher than 99.5％) to Sinorhizobium fredii USDA205. The analysis of the 16S—23S intergenic spacer (IGS) divided the isolates into 10 genotypes and four groups. The 16S—23S rDNA IGS sequencing assays divided the isolates into two groups. Group Ⅰ was clustered with Sinorhizobium fredii USDA205. Group Ⅱ was less similarity to Sinorhizobium fredii USDA205 than Sinorhizobium xinjiangense. The isolates from the subtropical regions of China had higher genetic similarity.%利用16S rDNA PCR-RELP、16S rDNA基因序列分析以及16S-23S rDNA IGS PCRRELP技术,对分离自我国江苏盐城、浙江温州、湖北仙桃及重庆等亚热带地区的31株大豆快生型根瘤茵(fast-growing rhizobia)进行了群体遗传多样性研究.16S rDNA PCR-RELP分析结果表明,所有供试大豆根瘤菌都与费氏中华根瘤菌USDA205聚成一类.供试代表菌株YcS2的16S rDNA基因序列与费氏中华根瘤菌USDA205的该序列相似性超过99.5%.16S-23S rDNA IGS PCR-RFLP研究结果表明:所有供试菌株分为10个基因型,在87%的相似性上分为4个类群.在此基础上筛选出10个代表菌株进行16S-23S rDNA基因序列分析,结果表明,10个供试菌株分为2个群,群Ⅱ(YcS3、ZzS1、YcS14)与新疆中华根瘤茵CCBAU110聚在一起,群I(其余7个菌株)与费氏中华根瘤茵USDA205聚在一起.中国亚热带地区的快生型大豆根瘤茵具有高度的相似性.