川中丘陵地区大豆根瘤菌遗传多样性与系统发育关系

Genetic diversity and phylogeny of soybean rhizobia isolated from the Hilly Area of Central Sichuan in China

摘要:

摘要:【目的】研究分离自川中丘陵地区大豆根瘤菌的遗传多样性和系统发育。【方法】采用16S rDNAPCR-RFLP和16S rRNA 基因、glnII、共生基因(nodC)系统发育分析的方法进行研究。【结果】供试未知菌的16S rDNA 用4种限制性内切酶(HaeⅢ、HinfⅠ、MspⅠ及TaqⅠ)酶切后获得5种16S遗传图谱类型。16S rDNA PCR-RFLP 结果表明，所有供试菌株在83% 水平分为慢生根瘤菌属(Bradyrhizobium)和中华根瘤菌属(Sinonrhizobium)两大类群，而75%的菌株为中华根瘤菌。6个代表菌株的16S rDNA、glnII和nodC三个位点 基因的系统发育结果基本一致，4 株与S.fredii USDA205T相似度最高;有2株分别与B.yuanmingense CCBAU10071T、B.diazoefficiens USDA110T相似度最高。4个Sinonrhizobium代表菌株16S rDNA、glnII序列相似度分别为98.3%－99.9%、98.2%－100%，但它们的nodC基因序列完全相同。【结论】川中丘陵地区大豆根瘤菌具有较丰富的遗传多样性，S.fredii为优势种。

Abstract:

Abstract:［Objective］We investigated the genetic diversity and phylogeny of 28 rhizobial isolates from root nodules of soybean growing in the Hilly Area of Central Sichuan in China.［Methods］We used 16S rDNA PCR-RFLP and phylogenetic analyses of the 16S rDNA，glnII and symbiotic genes (nodC).［Results］Five 16S rDNA genotypes among the isolates were distinguished with restriction endonucleases HaeⅢ，HinfⅠ，MspⅠand TaqⅠ．In the 16S rDNA PCRRFLP analysis，all the isolates are divided into Bradyrhizobium group and Sinonrhizobium group at the 83% level，and Sinonrhizobium strains accounted for 75% of the isolates．The phylogenetic analyses of 16S rDNA，glnII and nodC show that 4 representative strains SCAUs1，SCAUs2，SCAUs7 and SCAUs4 were closely related to S．fredii USDA205Twhile the other 2 representative strains SCAUs3 and SCAUs5 were closely related to B. yuanmingense CCBAU10071T and B． diazoefficiens USDA110T．The 16S rDNA，glnII and nodC sequence similarity of 4 Sinonrhizobium representative strains were 98.3%－99.9%，98.2%－100% and 100%，respectively.［Conclusion］Soybean rhizobia isolated from the Hilly Area of Central Sichuan in China has rich genetic diversity，S．fredii was the predominant genus.