College of Life Sciences, Shaanxi Key Laboratory of Molecular Biology for Agriculture, Northwest A & F University, Yangling, Shaanxi 712100, PR China.
Int J Syst Evol Microbiol. 2010 Nov;60(Pt 11):2552-2556. doi: 10.1099/ijs.0.019356-0. Epub 2009 Dec 11.
Previously, five rhizobial strains isolated from root nodules of Robinia pseudoacacia were assigned to the same genospecies on the basis of identical 16S rRNA gene sequences and phylogenetic analyses of the nodA, nodC and nifH genes, in which the five isolates formed a well-supported group that excluded other sequences found in public databases. In this study, the 16S rRNA gene sequence similarities between the isolates and Mesorhizobium mediterraneum UPM-Ca36(T) and Mesorhizobium temperatum SDW018(T) were 99.5 and 99.6 %, respectively. The five isolates were also different from defined Mesorhizobium species using ERIC fingerprint profiles and they formed a novel Mesorhizobium lineage in phylogenetic analyses of recA and atpD gene sequences. DNA-DNA relatedness values between the representative strain, CCNWYC 115(T), and type strains of defined Mesorhizobium species were found to be lower than 47.5 %. These results indicated that the isolates represented a novel genomic species. Therefore, a novel species, Mesorhizobium robiniae sp. nov., is proposed, with type strain CCNWYC 115(T) (=ACCC 14543(T) =HAMBI 3082(T)). Strain CCNWYC 115(T) can form effective nodules only on its original host.
先前，根据 16S rRNA 基因序列和 nodA、nodC 和 nifH 基因的系统发育分析，从刺槐根瘤中分离到的 5 株根瘤菌菌株被归为同一基因种，其中 5 个分离株形成了一个支持良好的群体，排除了其他在公共数据库中发现的序列。在这项研究中，分离株与中慢生根瘤菌 UPM-Ca36(T)和温带根瘤菌 SDW018(T)的 16S rRNA 基因序列相似性分别为 99.5%和 99.6%。这 5 个分离株还通过 ERIC 指纹图谱与已定义的中慢生根瘤菌物种不同，并且在 recA 和 atpD 基因序列的系统发育分析中形成了一个新的中慢生根瘤菌谱系。代表菌株 CCNWYC 115(T)与已定义的中慢生根瘤菌物种的模式菌株之间的 DNA-DNA 同源性值低于 47.5%。这些结果表明这些分离株代表了一个新的基因组种。因此，提出了一个新的物种，即罗宾氏中慢生根瘤菌（Mesorhizobium robiniae）sp. nov.，其模式菌株为 CCNWYC 115(T)（=ACCC 14543(T) = HAMBI 3082(T)）。菌株 CCNWYC 115(T)只能在其原始宿主上形成有效的根瘤。
