Coordenação de Aperfeiçoamento de Pessoal de Nível Superior, SBN, Quadra 2, Bloco L, Lote 06, Edifício Capes 70.040-020 Brasília, Distrito Federal, Brazil.
Embrapa Soja, C.P. 231, 86001-970 Londrina, Paraná, Brazil.
Int J Syst Evol Microbiol. 2019 Dec;69(12):3863-3877. doi: 10.1099/ijsem.0.003697.
The symbioses between legumes and nitrogen-fixing rhizobia make the greatest contribution to the global nitrogen input via the process of biological nitrogen fixation (BNF). stands out as the main genus nodulating basal Caesalpinioideae. We performed a polyphasic study with 11 strains isolated from root nodules of , an annual multi-functional native legume of the USA. In the 16S rRNA gene phylogeny the strains were clustered in the superclade. The results of analysis of the intergenic transcribed spacer (ITS) indicated less than 89.9 % similarity to other species. Multilocus sequence analysis (MLSA) with four housekeeping genes (, , and ) confirmed the new group, sharing less than 95.2 % nucleotide identity with other species. The MLSA with 10 housekeeping genes (, , , , , , , , and ) indicated as the closest species. Noteworthy, high genetic diversity among the strains was confirmed in the analyses of ITS, MLSA and BOX-PCR. Average nucleotide identity and digital DNA-DNA hybridization values were below the threshold of described species, of 89.7 and 40 %, respectively. In the and phylogenies, the strains were grouped together, but with an indication of horizontal gene transfer, showing higher similarity to and . Other phenotypic, genotypic and symbiotic properties were evaluated, and the results altogether support the description of the CNPSo strains as representatives of the new species sp. nov., with CNPSo 3426 (=USDA 10052=U686=CL 20) as the type strain.
豆科植物与固氮根瘤菌之间的共生关系通过生物固氮（BNF）过程对全球氮素输入做出了最大的贡献。根瘤菌属是结瘤的主要属，主要结瘤豆科植物的基本含羞草科。我们对从美国一年生多功能本地豆科植物根瘤中分离的 11 株菌进行了多相研究。在 16S rRNA 基因系统发育树中，这些菌株聚类在超群中。种间转录间隔区（ITS）分析结果表明，与其他根瘤菌属的相似性小于 89.9%。利用四个管家基因（、、和）的多位序列分析（MLSA）证实了这个新的群体，与其他物种的核苷酸同一性小于 95.2%。利用 10 个管家基因（、、、、、、、、和）的 MLSA 表明最接近的物种是。值得注意的是，ITS、MLSA 和 BOX-PCR 分析证实了菌株之间存在较高的遗传多样性。平均核苷酸同一性和数字 DNA-DNA 杂交值低于已描述的种的阈值，分别为 89.7%和 40%。在和的系统发育树中，这些菌株被归为一组，但有水平基因转移的迹象，与和显示出更高的相似性。还评估了其他表型、基因型和共生特性，结果完全支持 CNPSo 菌株被描述为新物种的代表，CNPSo 3426（=USDA 10052=U686=CL 20）作为模式菌株。
