Vibrio agarilyticus sp. nov., an agar-digesting marine bacterium isolated from coastal seawater in Daya Bay (Guangdong, China)

A Gram-strain-negative, facultatively anaerobic, motile, rod-shaped and flagellated marine bacterium, designated SM6 T , was isolated from surface seawater collected in Daya Bay (Guangdong, China). Phylogenetic analysis based on 16S rRNA gene sequences, multilocus sequence analysis, phylogenomic analysis of single-copy gene families and whole genome data showed that strain SM6 T belonged to the genus Vibrio . The closest phylogenetic relatives of SM6 T were Vibrio plantisponsor MSSRF60 T (97.38 % 16S rRNA gene sequence pairwise similarity), Vibrio variabilis R-40492 T (97.27 %), Vibrio aestuarianus ATCC 35048 T (97.21 %) and Vibrio sagamiensis LC2-047 T (97.3 %). Growth of strain SM6 T occurred at 10–45 °C (optimum 30 °C), at pH 6.0–9.0 (optimum 6.0) and in the presence of 0–10 % (w/v) NaCl (optimum 3–8 %). The predominant fatty acids (>10 %) were summed feature 3 (C 16 : 1 ω 7 c or/and C 16 : 1 ω 6 c ), C 16 : 0 and summed feature 8 (C 18 : 1 ω 7 c or/and C 18 : 1 ω 6 c ). The DNA G+C content of the assembled genomic sequences was 47.37 % for strain SM6 T . Average nucleotide identity values between SM6 T and its reference species were lower than the threshold for species delineation (95–96 %); in silico DNA–DNA hybridization further showed that the strains shared less than 70 % similarity. On the basis of evidence from the present polyphasic study, strain SM6 T is considered to represent a novel species of the genus Vibrio , for which the name Vibrio agarilyticus sp. nov. is proposed. The type strain is SM6 T (=KCTC 82076 T =MCCC 1K04327 T ).