sp. nov., a methylphosphonate-decomposing bacterium isolated from surface seawater in the Xisha Islands, PR China.

A Gram-stain-negative, facultative anaerobic, methylphosphonate-decomposing, motile by a polar flagellum and rod-shaped marine bacterium, designated S4B1, was isolated from the surface seawater collected from the Yongle Atoll (Xisha Islands, PR China). The pairwise alignment showed the highest sequence similarity of 97.5 and 96.6 % to subsp. 12_122_3T3 and HHS02, respectively. Phylogenetic analysis based on 16S rRNA gene and the phylogenomic analysis of single-copy genes showed that strain S4B1 belonged to the genus and formed a close branch with ZSDZ65. Growth of strain S4B1 occurred at 4-30 °C (optimum, 28 °C), at pH 6.0-8.0 (optimum, pH 7.0) and in the presence of 2-7 % (w/v) NaCl (optimum, 3 %). The predominant fatty acids (>10 %) were C16 : 0, iso-C and summed feature 3 (C 7 or/and C 6). The DNA G+C content of the assembled genomic sequence was 44.3 mol%. Average nucleotide identity (ANI) values between S4B1 and its reference species were lower than the threshold for species delineation (95-96 %), in which its highest ANI value with ZSDZ65 was 87.0 %. DNA-DNA hybridization further showed that strain S4B1 had less than 70 % similarity to its relatives. On the basis of the polyphasic evidence, strain S4B1 is proposed to represent a novel species of the genus , for which the name sp. nov. is proposed. The type strain is S4B1 (=KCTC 92311=MCCC 1K06168).