Pseudoruegeria aquimaris gen. nov., sp. nov., isolated from seawater of the East Sea in Korea

Abstract

A Gram-negative, non-motile, rod-shaped bacterial strain, SW-255T, was isolated from seawater from Hwajinpo, on the coast of the East Sea, Korea, and subjected to a polyphasic taxonomic study. Strain SW-255T grew optimally at pH 7.0-8.0 and 37°C in the presence of 2% (w/v) NaCl. It contained Q-10 as the predominant ubiquinone and C18:1ω7c as the major fatty acid. The DNA G+C content was 67.0 mol%. A neighbour-joining phylogenetic tree based on 16S rRNA gene sequences showed that strain SW-255T is phylogenetically closely related to the genera Ruegeria and Silicibacter of the Alphaproteobacteria. The levels of 16S rRNA gene sequence similarity between strain SW-255T and the type strains of Ruegeria atlantica and two Silicibacter species were in the range 95.8-96.2%. A phylogenetic tree based on gyrB sequences showed that strain SW-255T forms a distinct evolutionary lineage within the Alphaproteobacteria. Differential phenotypic properties, polar lipid profiles and DNA G+C contents, together with the phylogenetic distinctiveness, suggest that strain SW-255T should be distinguished from the members of the genera Ruegeria and Silicibacter. On the basis of the phenotypic, chemotaxonomic and phylogenetic data, strain SW-255T represents a novel genus and species, for which the name Pseudoruegeria aquimaris gen. nov., sp. nov. is proposed. The type strain of Pseudoruegeria aquimaris is SW-255T (=KCTC 12737T=JCM 13603T).