Colwellia mytili sp. nov., isolated from mussel Mytilus edulis

A Gram-stain-negative, aerobic, motile and rod-shaped bacterial strain, designated RA2-7^T, was isolated from a mussel (Mytilus edulis) collected from the South Sea, South Korea, and subjected to a taxonomic study using a polyphasic approach. Strain RA2-7^T grew optimally at 20^ºC, at pH 7.0-8.0 and in the presence of 2.0-3.0 % (w/v) NaCl. The phylogenetic trees based on 16S rRNA gene sequences showed that strain RA2-7^T belonged to the genus Colwellia. Strain RA2-7^T exhibited 16S rRNA gene sequence similarity values of 98.3, 98.0 and 97.5 % to the type strains of Colwellia sediminilitoris, Colwellia aestuarii and Colwellia polaris, respectively, and of 94.5-96.5 % to the type strains of the other species of the genus Colwellia. Strain RA2-7^T contained Q-8 as the predominant ubiquinone and summed feature 3 (C_16:1 ω7c and/or C_16:1ω6c) and C_16:0 as the major fatty acids. The major polar lipids detected in strain RA2-7^T were phosphatidylglycerol and phosphatidylethanolamine. The DNA G+C content of strain RA2-7^T was 39.0±0.04 mol% and its DNA-DNA relatedness values with the type strains of C. sediminilitoris, C. aestuarii and C. polaris were 14-19 %. Differential phenotypic properties, together with its phylogenetic and genetic distinctiveness, revealed that strain RA2-7^T is separated from recognized species of the genus Colwellia. On the basis of the data presented, strain RA2-7^T is considered to represent a novel species of the genus Colwellia, for which the name Colwellia mytili sp. nov. is proposed. The type strain is RA2-7^T (=KCTC 52417^T=NBRC 112381^T).