State Key Laboratory for Agro-Biotechnology, College of Biological Sciences, China Agricultural University, Beijing 100193, PR China.
Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, PR China.
Int J Syst Evol Microbiol. 2013 Feb;63(Pt 2):616-624. doi: 10.1099/ijs.0.034280-0. Epub 2012 Apr 27.
Thirteen slow-growing rhizobial strains isolated from root nodules of soybean (Glycine max L.) grown in Daqing city in China were classified in the genus Bradyrhizobium based on 16S rRNA gene sequence analysis. Multilocus sequence analysis of IGS, atpD, glnII and recA genes revealed that the isolates represented a novel clade in this genus. DNA-DNA relatedness lower than 42.5 % between the representative strain CCBAU 15774(T) and the type strains of the closely related species Bradyrhizobium liaoningense USDA 3622(T), Bradyrhizobium yuanmingense CCBAU 10071(T) and Bradyrhizobium betae LMG 21987(T), further confirmed that this group represented a novel species. CCBAU 15774(T) shared seven cellular fatty acids with the three above-mentioned species, but the fatty acids 15 : 0 iso and summed feature 5 (18 : 2ω6,9c and/or 18 : 0 anteiso) were unique for this strain. The respiratory quinone in CCBAU 15774(T) was ubiquinone-10 and the cellular polar lipids were phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine, cardiolipin and unknown aminolipid, polar lipid and phospholipid. In addition, some phenotypic features could be used to differentiate the novel group from the related species. On basis of these results, we propose the name Bradyrhizobium daqingense sp. nov., with CCBAU 15774(T) ( = LMG 26137(T) = HAMBI 3184(T) = CGMCC 1.10947(T)) as the type strain. The DNA G+C content of the type strain is 61.2 mol% (T(m)).
从中国大庆市生长的大豆根瘤中分离到的 13 株生长缓慢的根瘤菌菌株，根据 16S rRNA 基因序列分析，被归类为慢生根瘤菌属。IGS、atpD、glnII 和 recA 基因的多位序列分析显示，这些分离株代表了该属中的一个新分支。代表菌株 CCBAU 15774(T)与密切相关的物种辽宁慢生根瘤菌 USDA 3622(T)、元明串珠菌 CCBAU 10071(T)和野油菜黄单胞菌 LMG 21987(T)的模式菌株之间的 DNA-DNA 同源性低于 42.5%，进一步证实该组代表了一个新物种。CCBAU 15774(T)与上述三个物种共有七种细胞脂肪酸，但脂肪酸 15：0 iso 和特征脂肪酸 5（18：2ω6，9c 和/或 18：0 anteiso）是该菌株所特有的。CCBAU 15774(T)的呼吸醌是泛醌-10，细胞极性脂是磷脂酰乙醇胺、磷脂酰甘油、磷脂酰胆碱、心磷脂和未知的氨基脂、极性脂和磷脂。此外，一些表型特征可用于将新组与相关物种区分开来。基于这些结果，我们提出了慢生根瘤菌大庆亚种的新名称，以 CCBAU 15774(T)（=LMG 26137(T)=HAMBI 3184(T)=CGMCC 1.10947(T)）作为模式菌株。模式菌株的 DNA G+C 含量为 61.2 mol%（Tm）。
