Two Gram-stain-negative, catalase- and oxidase-positive, facultative anaerobic and rod-shaped motile bacteria, designated strains BEI176T and BEI207T, were isolated from seawater collected in the East China Sea. Phylogenetic analysis based on 16S rRNA gene sequences showed that strains BEI176T and BEI207T belonged to the genus Vibrio and were closely related to each other with 98.18 % similarity. The closest phylogenetic relatives of strain BEI176T were Vibrio alginolyticus LMG 4409T (98.85 %) and Vibrio campbellii LMG 11216T (98.81 %), whereas the closest relative of strain BEI207T was Vibrio hepatarius LMG 20362T (98.64 %). The two strains showed growth at different conditions; while strain BEI176T grew at 16-37 °C, pH 5.0-9.5 and 0-7.0 % (w/v) NaCl, the growth of strain BEI207T occurred at 10-37 °C, pH 6.0-9.5 and 1.0-7.0 % (w/v) NaCl. Both strains shared the same major fatty acid components of summed feature 3 (C16 : 1ω7c or C16 : 1ω6c), C16 : 0 and summed feature 8 (C18 : 1ω6c or C18 : 1ω7c). The DNA G+C contents of the assembled genomic sequences were 44.73 and 45.06 mol% for strains BEI176T and BEI207T, respectively. Average nucleotide identity values between the two strains and their reference species were lower than the threshold for species delineation (95-96 %); in silico DNA-DNA hybridization further showed that the two strains had less than 70 % similarity to their relatives. Therefore, two novel Vibrio species are proposed to accommodate them: Vibrioouci sp. nov. (type strain, BEI176T=MCCC 1K03515T=JCM 32690T= KCTC 62616T) and Vibrioaquaticus sp. nov. (type strain, BEI207T=MCCC 1K03516T=JCM 32691T=KCTC 62617T).
Keywords: East China Sea; Vibrio aquaticus; Vibrio ouci; seawater.