A Gram-stain-negative, aerobic, orange-pigmented, rod-shaped and non-motile bacterium, designated strain A6B8(T), was isolated from seawater of the Mariana Trench. The isolate grew at 4-50 °C (optimum 30-35 °C), at pH 6.5-8.0 (optimum pH 7.5) and with 0.5-4.0 % (w/v) NaCl (optimum 1.0-2.0 %). Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain A6B8(T) was related most closely to the genus Muriicola and shared highest sequence similarity of 97.7 % with Muriicola jejuensis EM44(T). Chemotaxonomic analysis showed menaquinone 6 (MK-6) was the predominant isoprenoid and iso-C15 : 0, iso-C15 : 1 G and iso-C17 : 0 3-OH were the major cellular fatty acids. The polar lipid profile of strain A6B8(T) included phosphatidylethanolamine, three unidentified aminolipids and four unidentified lipids. The genomic DNA G+C content was 47.1 mol%. The DNA-DNA relatedness value (23.3 %) clearly demonstrated that strains A6B8(T) and M. jejuensis EM44(T) were representatives of two different species. Based on the phenotypic, phylogenetic and chemotaxonomic characterizations, A6B8(T) ( = CGMCC 1.12606(T) = KCTC 32436(T)) is considered to be the type strain of a novel species of the genus Muriicola, for which the name Muriicola marianensis sp. nov. is proposed.
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