Rhizobium terrae sp. nov., Isolated from an Oil-Contaminated Soil in China

A Gram-stain-negative, facultative aerobic, non-spore-forming, non-motile, non-flagellated, rod-shaped bacterium, designated strain NAU-18^T was isolated from an oil-contaminated soil in China. Strain NAU-18^T could grow at 10-42 °C (optimum, 30 °C), at pH 5.0-8.0 (optimum, 7.0) and in the presence of 0-2.0% (w/v) NaCl (optimum, 0.5% NaCl in R2A). The predominant fatty acids were C_18:1ω7c (71.2%) and Summed feature 2 (5.1%), representing 76.3% of the total fatty acids. The major respiratory quinones were Q9 and Q10. The DNA G + C content of strain NAU-18^T was 61.4 mol% based on its draft genome sequence. Genome annotation of strain NAU-18^T predicted the presence of 6668 genes, of which 6588 are coding proteins and 80 are RNA genes. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain NAU-18^T was a member of the genus Rhizobium and showed 96.93% (with 93.2% coverage) and 96.81% (with 100% coverage) identities with those of Neorhizobium alkalisoli CCBAU 01393^T and Rhizobium oryzicola ZYY136^T, respectively. In the phylogenetic analysis, strain NAU-18^T and R. oryzicola ZYY136^T are consistently placed in the same branch. Strain NAU-18^T represents a novel species within the genus Rhizobium, for which the name Rhizobium terrae sp. nov. is proposed, with the type strain NAU-18^T (=KCTC 62418^T = CCTCC AB 2018075^T).