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【目的】研究黄土高原地区大豆根瘤菌的遗传多样性和系统发育。【方法】采用BOX-PCR、16S rDNAPCR-RFLP、16S-23S IGS PCR-RFLP和16S rRNA基因序列分析方法对分离自我国黄土高原地区4个省的15个地区的130株大豆根瘤菌及部分参比菌株进行了遗传多样性和系统发育分析。【结果】BOX-PCR反映的菌株多样性最丰富,形成的遗传群最多,16S rDNA PCR-RFLP方法在属、种水平上聚群较好,16S-23S IGSPCR RFLP反映的多样性介于BOX-PCR和16S rDNA PCR-RFLP之间,能够较好地反映出属、种和亲缘关系很近的菌株间的差异,3种方法聚类分析结果基本一致,可将所有供试菌株分为两大类群,中华根瘤菌属(Sinorhizobium)和慢生根瘤菌属(Bradyrhizobium)。从系统发育来看,供试的快生大豆根瘤菌为费氏中华根瘤菌(Sinorhizobium fredii),慢生大豆根瘤菌为日本慢生大豆根瘤菌(Bradyrhizobium japonicum)和辽宁慢生根瘤菌(Bradyrhizobium liaoningense)。【结论】我国黄土高原地区大豆根瘤菌具有较丰富的遗传多样性,S.fredii优势种,慢生大豆根瘤菌仅占10%,同时,分离到2株B.liaoningense。
【Objective】 The objective of this study was to investigate the genetic diversity and phylogeny of soybean rhizobia in the Loess Plateau. 【Method】 130 Rhizobium strains isolated from 15 regions of 4 provinces in the Loess Plateau of China were genotyped by BOX-PCR, 16S rDNA PCR-RFLP, 16S-23S IGS PCR-RFLP and 16S rRNA gene sequence analysis. Genetic diversity and phylogenetic analysis were performed on the strains. 【Result】 BOX-PCR showed the most abundant strains with the largest number of genetic groups formed. Cluster analysis by 16S rDNA PCR-RFLP method was better at genus and species level. The diversity of 16S-23S IGSPCR RFLP ranged from BOX- PCR and 16S rDNA PCR-RFLP, which can well reflect the genus, species and close genetic relationship between the strains of the three methods clustering analysis results are basically the same, all tested strains can be divided into two major Taxa, Sinorhizobium and Bradyrhizobium. In terms of phylogenetic analysis, the tested fast-growing soybean Rhizobium was Sinorhizobium fredii, the Bradyrhizobium japonicum and the Bradyrhizobium liaoningense ). 【Conclusion】 Rhizobium japonicum is rich in genetic diversity in the Loess Plateau of China. The S.fredii dominant species and the slow-growing soybean rhizobia accounted for only 10% of the total. At the same time, two strains of B.liaoningense were isolated.