Mesorhizobium carbonis sp. nov., isolated from coal bed water

A Gram-stain negative, aerobic, motile, short rod-shaped bacterium, designated as B2.3^T, was isolated from coal bed water collected from Jincheng, Shanxi Province, China. The strain was able to grow at 10-40 °C (optimum 28-30 °C), pH 4.0-10.0 (optimum 7.0), and in the presence of 0-5.0% NaCl (optimum 3.0%, w/v). Phylogenetic analysis based on the 16S rRNA and concatenated housekeeping gene recA, atpD and glnA sequences showed strain B2.3^T belongs to the genus Mesorhizobium, with Mesorhizobium oceanicum B7^T as the closely related type strain. Strain B2.3^T exhibited ANI value of 77.5% and GGDC value of 21.5% to M. oceanicum B7^T. The major fatty acids were identified as summed feature 8 (C_18:1ω7c and/or C_18:1ω6c) and 11-methyl C_18:1ω7c. The major polar lipids were found to consist of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine and an unidentified aminophospholipid. The predominant ubiquinone was identified as Quinone 10. Phenotypic and biochemical analysis results indicated that strain B2.3^T can be distinguished from closely related type strains. On the basis of phenotypic, genotypic and chemotaxonomic characteristics, strain B2.3^T is concluded to represent a novel species in the genus Mesorhizobium, for which the name Mesorhizobium carbonis sp. nov. is proposed. The type strain is B2.3^T (=CGMCC 1.15730^T = KCTC 52461^T).