Pseudomonas huanghezhanensis sp. nov. and Pseudomonas fjordensis sp. nov., two novel species isolated from seawater of Arctic Kongsfjorden in the Ny-Ålesund area, Svalbard

Abstract

Two Gram-stain-negative bacterial strains, BSw22131^T and DMSP-1^T, were isolated from seawater of Arctic Kongsfjorden in the Ny-Ålesund area, Svalbard. Strains BSw22131^T and DMSP-1^T were within the genus Pseudomonas and presented 98.1 and 99.8% 16S rRNA gene sequence similarity to Pseudomonas piscicola P50^T and Pseudomonas paracarnis V5/DAB/2/5^T, respectively. However, the results of multilocus sequence analysis (concatenated 16S rRNA, gyrB, rpoB and rpoD gene sequences) and whole-genome sequence analysis indicated that BSw22131^T and DMSP-1^T were most closely related to Pseudomonas petrae P2653^T and Pseudomonas lactis DSM 29167^T, respectively. The genome G+C contents of strains BSw22131^T and DMSP-1^T were 58.2 and 60.0%, respectively. The two isolates presented digital DNA-DNA hybridization and average nucleotide identity values of less than 70 and 96%, respectively, with type strain genomes of their close relatives. BSw22131^T contained summed feature 3 (C_{16 : 1} ω6c/C1_{6 : 1} ω7c), C_{16 : 0} and summed feature 8 (C_{18 : 1} ω6c/C1_{8 : 1} ω7c) as the major cellular fatty acids, whereas DMSP-1^T contained an additional C_{17 : 0}-cyclo as the major fatty acid. The major quinones of both strains were Q-9 (57.5-77.2%) and Q-8 (22.8-37.2%), and their major cellular polar lipids were diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylglycerol. BSw22131^T could be differentiated from its related species by positive ornithine decarboxylase, esterase (C8) and l-rhamnose and d-fructose-6-PO₄ utilization, whereas DMSP-1^T could be differentiated by positive acid phosphatase but negative p-hydroxyphenylacetic acid utilization. The two strains were negative for the reduction of nitrates but contained genes related to dimethylsulfoniopropionate catabolism. The results of the polyphasic taxonomy analysis revealed that strains BSw22131^T and DMSP-1^T represent two novel species of the genus Pseudomonas, for which the names Pseudomonas huanghezhanensis sp. nov. (type strain BSw22131^T = CCTCC AB 2019135^T = JCM 36635^T = DSM 117336^T) and Pseudomonas fjordensis sp. nov. (type strain DMSP-1^T = CCTCC AB 2019124^T = JCM 36636^T = DSM 117337^T) are proposed.

Keywords: Pseudomonas fjordensis; Pseudomonas huanghezhanensis; Svalbard; arctic; seawater.