Thalassotalea ponticola sp. nov., isolated from seawater, reclassification of Thalassomonas fusca as Thalassotalea fusca comb. nov. and emended description of the genus Thalassotalea

Abstract

A Gram-stain-negative, aerobic, non-flagellated and rod-shaped or ovoid bacterial strain, designated GJSW-36(T), was isolated from seawater at Geoje island in the South Sea, South Korea. Strain GJSW-36(T) grew optimally at pH 7.0-8.0, at 25 °C and in the presence of 2% (w/v) NaCl. A neighbour-joining phylogenetic tree based on 16S rRNA gene sequences showed that strain GJSW-36(T) fell within the clade comprising the type strains of species of the genus Thalassotalea and Thalassomonas fusca. Strain GJSW-36(T) exhibited 16S rRNA gene sequence similarity values of 94.2-96.0% to the type strains of species of the genus Thalassotalea and Thalassomonas fusca and of 93.8-94.5% to the type strains of the other species of the genus Thalassomonas. Strain GJSW-36(T) contained ubiquinone-8 (Q-8) as the predominant ubiquinone and summed feature 3 (C(16:1)ω7c and/or C(16:1)ω6c), C(1:1)ω8c and C(16:0) as the major fatty acids. The major polar lipids of strain GJSW-36(T) were phosphatidylglycerol and phosphatidylethanolamine. The DNA G+C content of strain GJSW-36(T) was 45.1 mol%. Differential phenotypic properties, together with the phylogenetic distinctiveness, demonstrated that strain GJSW-36(T) is separated from species of the genus Thalassotalea and Thalassomonas fusca. On the basis of the data presented, strain GJSW-36(T) is considered to represent a novel species of the genus Thalassotalea, for which the name Thalassotalea ponticola sp. nov. is proposed. The type strain is GJSW-36(T) ( =KCTC 42155(T) =CECT 8656(T)). From this study, it is also proposed that Thalassomonas fusca should be reclassified as a member of the genus Thalassotalea and the description of the genus Thalassotalea is emended.