Hyphomonas beringensis sp. nov. and Hyphomonaschukchiensis sp. nov., isolated from surface seawater of the Bering Sea and Chukchi Sea

Two Gram-negative, non-spore-forming, oval to pear shaped motile strains, designated 25B14_1T and BH-BN04-4T, isolated from surface seawater from the Bering Sea and Chukchi Sea, respectively, were subjected to polyphasic taxonomic study. Phylogenetic analysis based on 16S rRNA gene sequences demonstrated that strains 25B14_1T and BH-BN04-4T clustered together with Hyphomonas atlanticus 22II1-22F38T and Hyphomonas oceanitis DSM 5155T, respectively, within genus Hyphomonas. Based on whole genome sequence analysis, the calculated DDH and ANIm values between strain 25B14_1T and BH-BN04-4T are 18.8 and 83.19 % respectively. The calculated DDH values of strain 25B14_1T and BH-BN04-4T with seven type strains ranged from 18.2 to 19.9 % and from 18.4 to 40.4 %, respectively. The ANIm values of strain 25B14_1T and BH-BN04-4T with seven type strains ranged from 83.00 to 84.67 % and from 83.14 to 90.58 %, respectively. Both isolates were found to contain Q-11 as the predominant respiratory quinone. The major fatty acids of strain 25B14_1T were identified as C16:0, C17:0, C18:1ω7c-methyl and Summed Feature 8 (C18:1ω6c/ω7c as defined by MIDI), while in the case of strain BH-BN04-4T they were identified as C16:0, C18:1ω7c-methyl and Summed Feature 8 (C18:1ω6c/ω7c). The G+C contents of 25B14_1T and BH-BN04-4T were determined to be 58.4 and 61.0 mol%, respectively. The combined phenotypic and genotypic data show that the two isolates each represent novel species of the genus Hyphomonas, for which the names Hyphomonas beringensis sp. nov. and Hyphomonaschukchiensis sp. nov. are proposed, with the type strain 25B14_1T (=MCCC 1A07321T = LMG 27914T) and BH-BN04-4T (=MCCC 1A07481T = LMG 27915T), respectively.