Vibrio coralinecrosis sp. nov., a coral pathogen isolated from the stony coral Galaxea fascicularis in the South China Sea

A Gram-stain-negative, facultatively anaerobic, motile and rod-shaped bacterium, designated as strain SCSIO 43001 T , was isolated from the gastric cavity of the stony coral Galaxea fascicularis in the South China Sea. Previous studies identified this strain as a temperature-dependent coral pathogen, and further ecological analysis revealed that this species is also distributed among other marine invertebrates, including the Pacific oyster Magallana gigas . Strain SCSIO 43001 T grew at 10–40 °C (optimum, 28 °C), pH 6.0–10.0 (optimum, 7.0) and in 0.5–10% (w/v) NaCl (optimum, 3–4%). Phylogenetic analysis based on 16S rRNA gene sequences showed that strain SCSIO 43001 T belongs to the genus Vibrio , sharing the highest similarities with Vibrio japonicus LMG 29636 T (98.2%) and Vibrio xuii LMG 21346 T (97.9%). However, phylogenomic comparisons showed that the average nucleotide identity and digital DNA–DNA hybridization values between strain SCSIO 43001 T and its closest relatives were below 86.6 and 31.1%, respectively, well below the species-delimitation thresholds. The major cellular fatty acids were summed feature 3 (C 16 : 1 ω 7 c /C 16 : 1 ω 6 c ), summed feature 8 (C 18 : 1 ω 6 c or C 18 : 1 ω 7 c ) and C 16 : 0 . The DNA G+C content was 44.5 mol%. Based on combined phenotypic, chemotaxonomic, phylogenetic and phylogenomic polyphasic evidence, strain SCSIO 43001 T represents a novel species within the genus Vibrio , for which the name Vibrio coralinecrosis sp. nov. is proposed with the type strain SCSIO 43001 T (=MCCC 1K09368 T =KCTC 18156 T ).