Zhao Juan-Juan, Zhang Jun, Sun Lei, Zhang Rui-Jie, Zhang Cai-Wen, Yin Hua-Qun, Zhang Xiao-Xia
Key Laboratory of Microbial Resources Collection and Preservation, Ministry of Agriculture, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, PR China.
College of Life Sciences, Hebei University, Baoding 071002, PR China.
Int J Syst Evol Microbiol. 2017 Apr;67(4):963-968. doi: 10.1099/ijsem.0.001724. Epub 2017 May 5.
Two Gram-stain-negative, aerobic, rod-shaped endophytic bacterial strains, N19T and N11-2, were isolated from fresh rice (Oryza sativa) roots during investigation of the rice endophytic bacterial diversity. The 16S rRNA gene sequence results indicated that the similarity between strains N19T and N11-2 was 100 %. Both of them belong to the genus Rhizobium, with close similarity to Rhizobium taibaishanense CCNWSX 0483T (97.7 %), followed by Rhizobium vitis NCPPB 3554T (97.5 %). The sequence similarities of the housekeeping genes recA, gyrB and glnA between the novel isolates and members of the established species of the genus Rhizobium were less than 87 %. The DNA-DNA hybridization rates between strains N19T and N11-2 were 87.9 % using the initial renaturation rate method. Based on draft genome sequences, strain N19T showed 18.2 % and 19.6 % DNA-DNA hybridization values to R. taibaishanense CCNWSX 0483T and R. vitis S4, which demonstrated that these new isolates represent a novel species in the genus Rhizobium. The main cellular fatty acids were summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c). The DNA G+C content of strain N19T was 58.7 mol% (Tm). The polar lipid profile of N19T consisted of phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, an unknown lipid, two unknown aminolipids and an unidentified aminophospholipid. According to physiological and biochemical characteristics and genotypic data, strains N19T and N11-2 are considered to represent a novel species of the genus Rhizobium, for which the name Rhizobium oryziradicis sp. nov. is proposed, with N19T (=ACCC 19962T=KCTC 52413T) as the type strain.
在对水稻内生细菌多样性的调查过程中，从新鲜水稻（Oryza sativa）根部分离出两株革兰氏染色阴性、需氧、杆状的内生细菌菌株，N19T和N11 - 2。16S rRNA基因序列结果表明，菌株N19T和N11 - 2之间的相似性为100%。它们均属于根瘤菌属，与太白根瘤菌CCNWSX 0483T（97.7%）相似性较高，其次是葡萄根瘤菌NCPPB 3554T（97.5%）。新分离菌株与根瘤菌属已确立物种成员之间看家基因recA、gyrB和glnA的序列相似性低于87%。使用初始复性速率法，菌株N19T和N11 - 2之间的DNA - DNA杂交率为87.9%。基于草图基因组序列，菌株N19T与太白根瘤菌CCNWSX 0483T和葡萄根瘤菌S4的DNA - DNA杂交值分别为18.2%和19.6%，这表明这些新分离菌株代表根瘤菌属中的一个新物种。主要细胞脂肪酸为总和特征8（C18 : 1ω7c和/或C18 : 1ω6c）。菌株N19T的DNA G + C含量为58.7 mol%（Tm）。N19T的极性脂质谱由磷脂酰甘油、双磷脂酰甘油、磷脂酰乙醇胺、磷脂酰胆碱、一种未知脂质、两种未知氨基脂质和一种未鉴定的氨基磷脂组成。根据生理生化特征和基因型数据，菌株N19T和N11 - 2被认为代表根瘤菌属的一个新物种，为此提出名为水稻根瘤菌（Rhizobium oryziradicis sp. nov.），以N19T（=ACCC 19962T = KCTC 52413T）作为模式菌株。
