Arsukibacterium indicum sp. nov., isolated from deep-sea sediment, and transfer of Rheinheimera tuosuensis and Rheinheimera perlucida to the genus Arsukibacterium as Arsukibacterium tuosuense comb. nov. and Arsukibacterium perlucidum comb. nov.

A Gram-stain-negative, aerobic, flagellated and rod-shaped bacterium, designated strain SM2107T, was isolated from a deep-sea sediment sample collected from the Southwest Indian Ocean. Strain SM2107Tgrew at 4–40 °C and with 0–10.0 % (w/v) NaCl. It reduced nitrate to nitrite and hydrolysed casein, gelatin, chitin and DNA. The phylogenetic trees based on the 16S rRNA genes and single-copy orthologous clusters showed that strain SM2107T, together withRheinheimera tuosuensis,Rheinheimera perlucidaandArsukibacterium ikkense, formed a separate clade, having the highest similarity to the type strain ofRheinheimera tuosuensis(98.3%). The major polar lipids were phosphatidylethanolamine and phosphatidylglycerol and the major cellular fatty acids were summed feature 8 (C18 : 1ω7cand/or C18 : 1ω6c), C16 : 0, C17 : 1ω8сand summed feature 3 (C16 : 1ω7cand/or C16 : 1ω6c). The only respiratory quinone was Q-8. The genomic DNA G+C content of strain SM2107Twas 48.8 %. The digital DNA–DNA hybridization values between strain SM2107Tand type strains ofRheinheimera tuosuensis,Rheinheimera perlucidaandArsukibacterium ikkensewere 41.16, 37.70 and 31.80 %, while the average amino acid identity values between them were 87.59, 86.76 and 83.64 %, respectively. Based on the polyphasic evidence presented in this study, strain SM2107Twas considered to represent a novel species within the genusArsukibacterium, for which the nameArsukibacterium indicumwas proposed. The type strain is SM2107T(=MCCC M24986T=KCTC 82921T). Moreover, the transfer ofRheinheimera tuosuensisandRheinheimera perlucidato the genusArsukibacteriumasArsukibacterium tuosuensecomb. nov. (type strain TS-T4T=CGMCC 1.12461T=JCM 19264T) andArsukibacterium perlucidumcomb. nov. (type strain BA131T=LMG 23581T=CIP 109200T) is also proposed.