Li Yong Hua, Wang Rui, Zhang Xiao Xia, Young J Peter W, Wang En Tao, Sui Xin Hua, Chen Wen Xin
State Key Lab for Agro-Biotechnology, Ministry of Agriculture Key Lab of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing, 100193, PR China.
Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, PR China.
Int J Syst Evol Microbiol. 2015 Dec;65(12):4655-4661. doi: 10.1099/ijsem.0.000629. Epub 2015 Sep 23.
Seven slow-growing rhizobia isolated from effective nodules of Arachis hypogaea were assigned to the genus Bradyrhizobium based on sharing 96.3-99.9 % 16S rRNA gene sequence similarity with the type strains of recognized Bradyrhizobium species. Multilocus sequence analysis of glnII, recA, gyrB and dnaK genes indicated that the seven strains belonged to two novel species represented by CCBAU 51649T and CCBAU 53363T. Strain CCBAU 51649T shared 94, 93.4, 92.3 and 94.9 % and CCBAU 53363T shared 91.4, 94.5, 94.6 and 97.7 % sequence similarity for the glnII, recA, gyrB and dnaK genes, respectively, with respect to the closest related species Bradyrhizobium manausense BR 3351T and Bradyrhizobium yuanmingense CCBAU 10071T. Summed feature 8 and C16 : 0 were the predominant fatty acid components for strains CCBAU 51649T and CCBAU 53363T. DNA-DNA hybridization and analysis of phenotypic characteristics also distinguished these strains from the closest related Bradyrhizobium species. The strains formed effective nodules on Arachis hypogaea, Lablab purpureus and Aeschynomene indica, and they had identical nodA genes to Bradyrhizobium sp. PI237 but were phylogenetically divergent from other available nodA genes at less than 66 % similarity. Based in these results, strains CCBAU 51649T ( = CGMCC 1.15034T = LMG 28620T) and CCBAU 53363T ( = CGMCC 1.15035T = LMG 28621T) are designated the type strains of two novel species, for which the names Bradyrhizobium guangdongense sp. nov. and Bradyrhizobium guangxiense sp. nov. are proposed, respectively.
从花生有效根瘤中分离出的7株慢生根瘤菌，基于其16S rRNA基因序列与已确认的慢生根瘤菌属模式菌株的相似性为96.3 - 99.9%，被归为慢生根瘤菌属。对谷氨酰胺合成酶基因（glnII）、重组酶A基因（recA）、DNA回旋酶B亚基基因（gyrB）和热休克蛋白基因（dnaK）进行多位点序列分析表明，这7株菌属于以CCBAU 51649T和CCBAU 53363T为代表的两个新物种。菌株CCBAU 51649T的glnII、recA、gyrB和dnaK基因序列与最相近的曼氏慢生根瘤菌BR 3351T和圆明慢生根瘤菌CCBAU 10071T的相似性分别为94%、93.4%、92.3%和94.9%，菌株CCBAU 53363T的相应相似性分别为91.4%、94.5%、94.6%和97.7%。特征性脂肪酸8和C16 : 0是菌株CCBAU 51649T和CCBAU 53363T的主要脂肪酸成分。DNA - DNA杂交和表型特征分析也将这些菌株与最相近的慢生根瘤菌属物种区分开来。这些菌株能在花生、扁豆和印度合萌上形成有效根瘤，它们的nodA基因与慢生根瘤菌PI237相同，但在系统发育上与其他已知的nodA基因分歧较大，相似性低于66%。基于这些结果，菌株CCBAU 51649T（= CGMCC 1.15034T = LMG 28620T）和CCBAU 53363T（= CGMCC 1.15035T = LMG 28621T）分别被指定为两个新物种的模式菌株，分别命名为广东慢生根瘤菌（Bradyrhizobium guangdongense sp. nov.）和广西慢生根瘤菌（Bradyrhizobium guangxiense sp. nov.）。
