Thetidibacter halocola gen. nov., sp. nov., a novel member within the family Roseobacteraceae isolated from seawater

A Gram-staining-negative, strictly aerobic, dark beige-colored, rod-shaped, chemoorganoheterotrophic, and catalase- and oxidase-positive bacterium, designated as KMU-90(T), was isolated from coastal seawater in the Republic of Korea, and subjected to a polyphasic study. The novel isolate was able to grow at 0-6.0% NaCl concentrations (w/v), pH 6.5-9.5, and 4-45 ?. The 16S rRNA gene sequences-based phylogeny revealed that the novel marine isolate belongs to the family Roseobacteraceae of class Alphaproteobacteria and that it shared the greatest sequence similarity (97.3%) with Aestuariicoccus marinus NAP41(T). The novel strain could be distinguished phenotypically from related representatives of the family Roseobacteraceae. The major (> 10%) fatty acids of strain KMU-90(T) were C-18:1?7c and C-18:1?7c 11-methyl and the only respiratory quinone was ubiquinone-10 (Q-10). Strain KMU-90(T) contained phosphatidylethanolamine, phosphatidylcholine, phosphatidylglycerol, two unidentified aminolipids, an unidentified phospholipid, and three unidentified glycolipids as polar lipids. The assembled draft genome size of strain KMU-90(T) was 4.84 Mbp with a DNA G + C content of 66.5%. The average nucleotide identity, digital DNA-DNA hybridization, and average amino acid identity values between the genomes of strain KMU-90(T) and its closely related representatives were 77.0-79.0%, 14.6-20.0%, and 60.0-69.9%, respectively. From the polyphasic taxonomic results obtained, the strain is considered to represent a novel genus and a new species of the family Roseobacteraceae, for which the name Thetidibacter halocola gen. nov., sp. nov. is proposed. The type species is T. halocola, with the type strain KMU-90(T) (= KCCM 90287(T) = NBRC 113375(T)).