Mesobaculum littorinae gen. nov., sp. nov., a novel bacterium isolated from a sea snail Littorina scabra.

Members within the family Rhodbacteraceae are morphologically and genetically highly diverse, and originate mostly from coastal marine environments. In this study, a novel species of this family, designated M0103T, was isolated from the surface of a sea snail Littorina scabra. Strain M0103T is Gram-stain-negative, halophilic, non-motile and non-Bacteriochlorophyll a-producing bacterium. Several phenotypic characteristics of the isolate were similar to other species within this family, such as the sole respiratory quinone Q-10 and major fatty acid components C18 : 1 ω7c, C18 : 0 and C16 : 0. Strain M0103T contains a diphosphatidylglycerol, a phosphatidylglycerol, a phosphatidylcholine, a phosphatidy ethanolamine, a phosphatidylinositol, five unidentified phospholipids and four unidentified polar lipids. Based on the 16S rRNA gene sequence analysis, this isolate showed the closest phylogenetic relationship with 'Palleronia pontilimi' GH1-23T (95.1 %). Values of average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) of genome sequences were of 70.1-76.4 % and 18.3-20.9 % between the isolate and 24 closely related type strains. Analysis the 4.0 Mb genome of strain M0103T revealed several putative genes associated with cellular stress resistance, which may play protective roles for the isolate in the adaptation to a marine environment. Phylogenetic, phenotypic and chemotaxonomic analyses suggested that strain M0103T represents a novel genus and novel species of the family Rhodobacteraceae, for which the name Mesobaculum littorinae gen. nov., sp. nov. is proposed. The type strain is M0103T (=MCCC 1K03619T=KCTC 62358T).