Kangsaoukella pontilimi gen. nov., sp. nov., a new member of the family Rhodobacteraceae isolated from a tidal mudflat

Abstract

A strictly aerobic, Gram-stain-negative, non-motile, ovoid- and rod-shaped bacterium, designated strain GH1-50T, was isolated from a tidal mudflat sample collected from Dongmak seashore on Gangwha Island, Republic of Korea. The organism showed growth at 20–40 °C (optimum, 30 °C), pH 7–8 (optimum, pH 7) and 2–6  % (w/v) NaCl (optimum, 5 %). The pufLM genes were present but bacteriochlorophyll a was not detected. The major isoprenoid quinone was Q-10. The polar lipids were phosphatidylcholine, phosphatidylglycerol, phosphatidylinositol, an unidentified aminolipid and five unidentified lipids. The predominant cellular fatty acids were C18 : 1  ω7c, C18 : 1  ω7c 11-methyl and C18 : 0. Phylogenetic analysis based on 16S rRNA gene sequence comparisons revealed that the isolate belonged to the family Rhodobacteraceae and was loosely associated with members of the recognized genera. The closest relative was the type strain of Pseudoruegeria marinistellae (96.8 % similarity) followed by Boseongicola aestuarii (96.4 %). Other members of the family shared 16S rRNA gene similarity values below 96.0 % to the novel isolate. The DNA G+C content calculated from the draft genome sequence was 64.0 %. The average amino acid identity, average nucleotide identity and digital DNA–DNA hybridization values between genome sequences of strain GH1-50T and all the type strains of the recognized taxa compared were <70.0, <84.1 and <20.5 %, respectively. Based on data obtained by a polyphasic approach, strain GH1-50T (=KCTC 72224T=NBRC 113929T) represents a novel species of a new genus in the family Rhodobacteraceae , for which the name Kangsaoukella pontilimi gen. nov., sp. nov. is proposed.