黑木相思根瘤菌遗传多样性

Biodiversity of Rhizobia associated with Acacia melanoxylon grown in South China

【目的】研究分离自广东、福建、江西等15个地点的174株黑木相思(Acacia melanoxylon)根瘤菌的遗传多样性。【方法】采用16S rDNA限制性片段长度多态性分析(Restriction fragment length polymorphism,RFLP)和16S rDNA基因、持家基因(recA、atpD、glnII)系统发育分析的方进行研究。【结果】16S rDNAPCR-RFLP分析中,在70%的相似性水平上,所有供试菌株分成9个类群;16S rDNA基因和持家基因系统发育分析结果基本一致,34株代表菌株主要分布在α-变形菌纲(Alpha-Proteobacteria)的慢生根瘤菌属(Bradyrhizobium)、根瘤菌属(Rizobium)、中慢生根瘤菌属(Mesorhizobium),并与Bradyrhizobium liaoningense、Bradyrhizobium betae、Bradyrhizobium cytisi、Rizobium multihospitium、Mesorhizobium plurifarium亲缘关系较近。【结论】供试菌株被鉴定到属的水平,Bradyrhizobium、Rhizobium或Mesorhizobium为优势菌群,证明了黑木相思根瘤菌具有丰富的遗传多样性。

[Objective]This study aimed to investigate the genetic diversity of 174 isolates of symbiotic bacteria associated with Acacia melanoxylon obtained from 15 sampling sites in Guangdong,Fujian and Jiangxi provinces of China.[Methods]The 16S rDNA restriction fragment length polymorphism（RFLP） and phylogenetic analyses of the 16S rDNA and housekeeping genes（recA,glnII and atpD）.[Results]In the 16S rDNA PCR-RFLP analysis,9 rDNA types were identified among the 174 isolates;Phylogenetic analyses based on 16S rDNA and housekeeping gene sequences indicated that 34 representative isolates belonged to the genus Bradyrhizobium,Rhizobium,Mesorhizobium in Alpha-Proteobacteria,and the most closely related strains are Bradyrhizobium liaoningense,Bradyrhizobium betae,Bradyrhizobium cytisi,Rhizobium multihospitium and Mesorhizobium plurifarium.[Conclusion]All of the isolates could be identified to general,and Bradyrhizobium,Rhizobium or Mesorhizobium could be the dominant microsymbiont.The microsymbionts associated with Acacia melanoxylon showed relative genetic diversity.