Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria 0002, Gauteng, South Africa.
The James Hutton Institute, Invergowrie, Dundee DD2 5DA, UK.
Syst Appl Microbiol. 2023 Sep;46(5):126452. doi: 10.1016/j.syapm.2023.126452. Epub 2023 Aug 18.
A genealogical concordance approach was used to delineate strains isolated from Acacia dealbata and Acacia mearnsii root nodules in South Africa. These isolates form part of Bradyrhizobium based on 16S rRNA sequence similarity. Phylogenetic analysis of six housekeeping genes (atpD, dnaK, glnII, gyrB, recA and rpoB) confirmed that these isolates represent a novel species, while pairwise average nucleotide identity (ANIb) calculations with the closest type strains (B. cosmicum 58S1, B. betae PL7HG1, B. ganzhouense CCBAU 51670 , B. cytisi CTAW11 and B. rifense CTAW71) resulted in values well below 95-96%. We further performed phenotypic tests which revealed that there are high levels of intraspecies variation, while an additional analysis of the nodA and nifD loci indicated that the symbiotic loci of the strains are closely related to those of Bradyrhizobium isolates with an Australian origin. Strain 14AB (=LMG 31415 = SARCC-753 ) is designated as the type strain of the novel species for which we propose the name Bradyrhizobium xenonodulans sp. nov.
采用系统发育一致性方法对南非银荆和马占相思根瘤菌进行了菌株分离。这些分离株基于 16S rRNA 序列相似性，属于慢生根瘤菌。六个管家基因(atpD、dnaK、glnII、gyrB、recA 和 rpoB)的系统发育分析证实，这些分离株代表了一个新种，而与最接近的模式菌株(B.cosicum 58S1、B.betae PL7HG1、B.ganzhouense CCBAU 51670、B.cytisi CTAW11 和 B.rifense CTAW71)的两两平均核苷酸同一性(ANIb)计算值远低于 95-96%。我们进一步进行了表型测试，结果表明存在高水平的种内变异，而对 nodA 和 nifD 基因座的进一步分析表明，这些菌株的共生基因座与具有澳大利亚起源的慢生根瘤菌分离株密切相关。菌株 14AB(=LMG 31415 =SARCC-753)被指定为新种的模式株，我们提议将其命名为 Xenonodulans sp. nov. 。
