Thalassotalea psychrophila sp. nov., Thalassotalea nanhaiensis sp. nov. and Thalassotalea fonticola sp. nov., three psychrophilic bacteria isolated from deep-sea sediment

Three psychrophilic bacteria, designated as strains SQ149 T , SQ345 T , and S1-1 T , were isolated from deep-sea sediment from the South China Sea. All three strains were the most closely related to Thalassotalea atypica RZG4-3-1 T 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 Thalassotalea . The average amino acid identity, average nucleotide identity, and digital DNA–DNA hybridization values among the three strains and closest Thalassotalea 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 16 : 1 ω7 c and/or C 16 : 1 ω6 c ) 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 Thalassotalea , for which the names Thalassotalea psychrophila sp. nov. (type strain SQ149 T =MCCC 1K04231 T =JCM 33807 T ), Thalassotalea nanhaiensis sp. nov. (type strain SQ345 T =MCCC 1K04232 T =JCM 33808 T ), and Thalassotalea fonticola sp. nov. (type strain S1-1 T =MCCC 1K06879 T =JCM 34824 T ) are proposed.