Spongiibacter thalassae sp. nov., a marine gammaproteobacterium isolated from seawater

Abstract

A bacterium, designated as KMU-166^T, belonging to the class Gammaproteobacteria, was isolated from seawater collected on the coastline of Dadaepo, Republic of Korea. Strain KMU-166^T was Gram-staining-negative, ovoid-shaped, motile, strictly aerobic, beige-colored, catalase-positive, and oxidase-negative; and had a chemoorganoheterotrophic metabolism. The novel isolate was found to grow at 1-4% NaCl concentrations (w/v), pH 6.5-9.5, and 10-40 °C. The 16S rRNA gene sequence-based phylogeny showed that strain KMU-166^T affiliates to the family Spongiibacteraceae and that it shared the greatest sequence similarity (96.4%) with Spongiibacter marinus HAL40b^T. The main (> 10%) cellular fatty acids were summed feature 3 (C16:1ω7c and/or C16:1ω6c), C17:1ω8c, and C18:1ω7c. The predominant respiratory quinone was ubiquinone-8 (Q-8). Strain KMU-166^T comprised phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, and two unidentified lipids. The assembled draft genome was 4.40 Mbp in size with a DNA G+C content of 55.7%. The average nucleotide identity, digital DNA-DNA hybridization, and average amino acid identity values of KMU-166^T and Spongiibacter marinus HAL40b^T, Spongiibacter tropicus CL-CB221^T, and "Spongiibacter pelagi" KMU-158^T were found to be 77.7-79.8%, 13.7-15.4%, and 66.1-70.9%, respectively. From the distinguishable polyphasic taxonomic results obtained, the strain is considered to represent a novel species of the genus Spongiibacter for which the name Spongiibacter thalassae sp. nov. is proposed. The type strain of S. thalassae sp. nov. is KMU-166^T (= KCCM 90449^T = NBRC 114308^T).

Keywords: 16S rRNA gene sequence; Gammaproteobacteria; Genome sequence; Polyphasic taxonomy; Spongiibacter thalassae sp. nov.; Spongiibacteraceae.