A Gram-stain-negative, aerobic bacterium, strain M5T, was isolated from a seawater sample collected from the western Pacific Ocean at a depth of 1000 m and characterized by using polyphasic taxonomy. Cells of the strain were rod-shaped and motile by a single polar flagellum. Cells grew at 4-40 °C (optimum, 25 °C), at pH 7-10 (optimum, 9) and with 0-10 % NaCl (optimum, 1-2 %). Phylogenetic trees based on 16S rRNA gene sequences showed that strain M5T was associated with the genus Pseudomonas, and showed highest similarities to Pseudomonas pelagia CL-AP6T (97.8 %) and Pseudomonas salina XCD-X85T (97.5 %) and Pseudomonas sabulinigri J64T (96.4 %). The average nucleotide identity scores for strains CL-AP6T and XCD-X85T were 74.6 % and 73.7 %, the Genome-to-Genome Distance Calculator scores were 15.8-19.5 % and 15.4-19.7 %, and the species identification scores were 92.3 % and 92.4 %. The major isoprenoid quinone of strain M5T was ubiquinone (Q-9) and the major cellular fatty acids were summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c; 33.2 %), summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c; 22.8 %) and C16 : 0 (13 %). The major polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phospholipid and some unidentified lipids. The phylogenetic analysis and physiological and biochemical data showed that strain M5T should be classified as representing a novel species in the genus Pseudomonas, for which the name Pseudomonas profundi sp. nov. is proposed. The type strain is M5T (=CCTCC AB 2017186T=KCTC 62119T=CICC 24308T).
Keywords: Pseudomonas; deep sea; genome.