sp. nov. sp. nov. and sp. nov., three psychrophilic bacteria isolated from deep-sea sediment.

Three psychrophilic bacteria, designated as strains SQ149, SQ345, and S1-1, were isolated from deep-sea sediment from the South China Sea. All three strains were the most closely related to RZG4-3-1 based on the 16S rRNA gene sequence analysis (similarity ranged from 96.45 to 96.67 %). Phylogenetic analysis based on the 16S rRNA gene and core-genome sequences showed that three strains formed a cluster within the genus . The average amino acid identity, average nucleotide identity, and digital DNA-DNA hybridization values among the three strains and closest species were far below the cut-off value recommended for delineating species, indicating they each represented a novel species. All three strains were Gram-stain-negative, rod-shaped, and contained summed feature 3 (C ω7 and/or C ω6) as the predominant fatty acid, Q-8 as the major respiratory quinone, and phosphatidylethanolamine and phosphatidylglycerol as predominant polar lipids. Based on the genomic, phylogenetic, and phenotypic characterizations, each strain is considered to represent a novel species within the genus , for which the names sp. nov. (type strain SQ149=MCCC 1K04231=JCM 33807), sp. nov. (type strain SQ345=MCCC 1K04232=JCM 33808), and sp. nov. (type strain S1-1=MCCC 1K06879=JCM 34824) are proposed.