Identification and classification of Croceivirga thetidis sp. nov., a marine Flavobacteriaceae isolated from the hard coral Acropora.

A taxonomic investigation using a polyphasic method was conducted to identify a novel marine flavobacterium, designated as DJ-13^T, isolated from the hard coral Acropora sp. collected at Okinawa, Japan. Bacterial cells were Gram-stain-negative, yellow-colored, strictly aerobic, rod-shaped, catalase- and oxidase-positive, non-motile, and chemoorganoheterotrophic. The novel isolate grew at NaCl concentrations of 0.5–7%, pH 6.5–9.0, and 15–37 °C. A phylogenetic study on the basis of the 16S rRNA gene sequence revealed that strain DJ-13^T belongs to the family Flavobacteriaceae and that it shared the greatest sequence similarity (95.9%) with Croceivirga lutea CSW06^T. Strain DJ-13^T comprised iso-C17:0 3-OH, iso-C15:0, and iso-C15:1 G as the main (> 10%) cellular fatty acids. Menaquinone-6 (MK-6) was the only respiratory quinone. The assembled draft genome size of strain DJ-13^T was 3.71 Mbp with G + C content of 38.7 mol%. The average nucleotide identity (ANI), digital DNA–DNA hybridization (dDDH), and average amino acid identity (AAI) values of DJ-13^T and the species of the genus Croceivirga were found to be 74.9–75.5%, 13.4–14.7%, and 68.2–72.4%, respectively. Strain DJ-13^T contained phosphatidylethanolamine, two unidentified aminolipids, and five unidentified lipids as polar lipids. From the polyphasic taxonomic results presented, the strain is considered to represent a novel species of the genus Croceivirga for which the name Croceivirga thetidis sp. nov. is proposed. The type strain of C. thetidis sp. nov. is DJ-13^T (= KCTC 72790^T = NBRC 114252^T). [ABSTRACT FROM AUTHOR]