Thalassomonas fusca sp. nov., a novel gammaproteobacterium isolated from tidal flat sediment

Abstract

A Gram-negative, aerobic, non-motile, dark brown-coloured and rod-shaped bacterial strain, designated G-MB1^T, was isolated from a tidal flat sediment of the South Sea, South Korea. Strain G-MB1^T was found to grow optimally at 25 °C, at pH 7.0–8.0 and in the presence of 2.0 % (w/v) NaCl. A neighbour-joining phylogenetic tree based on 16S rRNA gene sequences revealed that strain G-MB1^T fell within the clade comprising Thalassomonas species, clustering with the type strains of Thalassomonas agarivorans, Thalassomonas loyana, Thalassomonas ganghwensis and Thalassomonas agariperforans, with which it exhibited 16S rRNA gene sequence similarity values of 96.0–96.9 %. The 16S rRNA gene sequence similarity values between strain G-MB1^T and the type strains of the other Thalassomonas species were 94.6–95.1 %. Strain G-MB1^T was found to contain Q-8 as the predominant ubiquinone and C_16:0, C_17:1 ω8c, C_16:1 ω9c, C_12:0 3-OH and summed feature 3 (C_16:1 ω7c and/or C_16:1 ω6c) as the major fatty acids. The major polar lipids of strain G-MB1^T were phosphatidylglycerol, phosphatidylethanolamine and one unidentified aminolipid. The DNA G+C content of strain G-MB1^T was determined to be 42.4 mol%. Differential phenotypic properties, together with the phylogenetic distinctiveness, revealed that strain G-MB1^T is separated from other Thalassomonas species. On the basis of the data presented, strain G-MB1^T is considered to represent a novel species of the genus Thalassomonas, for which the name Thalassomonas fusca sp. nov. is proposed. The type strain is G-MB1^T (=KCTC 32499^T = NBRC 109830^T).