Vibrio ostreae sp. nov., a novel gut bacterium isolated from a Yellow Sea oyster

Abstract

A Gram-stain-negative, oxidase- and catalase-positive, facultative anaerobic motile bacterium, designated strain OG9-811^T, was isolated from the gut of an oyster collected in the Yellow Sea, Republic of Korea. The strain grew at 10-37 °C, pH 6.0-9.0 and with 0.5-10% (w/v) NaCl. Phylogenetic analysis based on the 16S rRNA gene sequences revealed that strain OG9-811^T affiliated with the genus Vibrio, with the highest sequence similarity of 98.2% to Vibrio coralliilyticus ATCC BAA-450^T followed by Vibrio variabilis R-40492^T (98.0 %), Vibrio hepatarius LMG 20362^T (97.7 %) and Vibrio neptunius LMG 20536^T (97.6 %); other relatives were Vibrio tritonius JCM 16456^T (97.4 %), Vibrio fluvialis NBRC 103150^T (97.0 %) and Vibrio furnissii CIP 102972^T (97.0 %). The complete genome of strain OG9-811^T comprised two chromosomes of a total 4 807 684 bp and the G+C content was 50.2 %. Results of analysis based on the whole genome sequence showed the distinctiveness of strain OG9-811^T. The average nucleotide identity (ANI) values between strain OG9-811^T and the closest strains V. coralliilyticus ATCC BAA-450^T, V. variabilis R-40492^T, V. hepatarius LMG 20362^T, V. neptunius KCTC 12702^T , V. tritonius JCM 16456^T, V. fluvialis ATCC 33809^T and V. furnissi CIP 102972^T were 73.0, 72.6, 73.3, 73.0, 72.7, 78.5 and 77.8 %, respectively, while the digital DNA-DNA hybridization values between strain OG9-811^T and the above closely related strains were 20.8, 21.2, 20.8, 21.7, 20.7, 23.2 and 22.4 %, respectively. The major fatty acids of strain OG9-811^T were summed feature 3 (C_16:1 ω7c and/or C_16:1 ω6c), summed feature 8 (C_18:1 ω6c and/or C_18:1 ω7c) and C_16:0. The polar lipids contained phosphatidylethanolamine, phosphatidylglycerol and diphosphatidylglycerol. Strain OG9-811^T contained Q-8 as a quinone. On the basis of polyphasic taxonomic characteristics, strain OG9-811^T is considered to represent a novel species, for which the name Vibrio ostreae sp. nov. is proposed. The type strain is OG9-811^T (=KCTC 72623^T=GDMCC 1.2610^T).

Keywords: gut of oyster; polyphasic taxonomy; proteobacteria.