Salinimonas iocasae sp. nov., a halophilic bacterium isolated from a polychaete tube in a hydrothermal field.

Abstract

A moderately halophilic bacterium, designated strain KX18D6T, was isolated from the tube of the polychaete Paralvinella hessleri collected from a hydrothermal field located in the Okinawa Trough. Strain KX18D6T was Gram-stain-negative, rod-shaped, facultatively anaerobic, motile, oxidase- and catalase-positive, and grew optimally at 30-35 °C, pH 7.0 and in the presence of 3-5 % (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain KX18D6T grouped with the members of the genus Salinimonas, including Salinimonas chungwhensis BH030046T (97.7 % sequence similarity), Salinimonas lutimaris DPSR-4T (97.2 %) and Salinimonas sediminis N102T (96.4 %). Genome sequencing of strain KX18D6T revealed a genome size of 4.16 Mb and a DNA G+C content of 47.3 mol%. Genomic average nucleotide identity (orthoANI) values of strain KX18D6T with S. chungwhensis DSM 16280T, S. lutimaris KCTC 23464T and S. sediminis N102T were 76.2, 73.1 and 73.2 %, respectively, while the in silico DNA-DNA hybridization (GGDC) values for strain KX18D6T with these strains were 25.3, 17.7 and 18.0 %, respectively. The major fatty acids were summed feature 3 (C16 : 1 ω7c/C16 : 1 ω6c), C16 : 0 and summed feature 8 (C18 : 1 ω7c/C18 : 1 ω6c). The predominant respiratory quinone was ubiquinone 8, and the predominant polar lipids were phosphatidylethanolamine and phosphatidylglycerol. On the basis of comparative analysis of phylogenetic, phylogenomic, phenotypic and chemotaxonomic characteristics, strain KX18D6T (=KCTC 72464T=MCCC 1K03884T) is clearly distinguishable from the type strains of species of the genus Salinimonas and is considered to represent a novel species of the genus Salinimonas, for which the name Salinimonas iocasae sp. nov. is proposed.