Delineating the key virulence factors and intraspecies divergence of Vibrio harveyi via whole-genome sequencing

Vibrio harveyi is one of the major pathogens in aquaculture. To identify key virulence factors affecting pathogenesis V. towards fish, we conducted a field investigation for three representative fish farms infected with harveyi. Multilocus sequence typing (MLST) and whole-genome sequencing were to delineate phylogenetic relationship genetic divergence A total 25 strains isolated from diseased groundwater subtyped into 12 types by MLST. Five genes, mshB, pilA, hutR, ureB, ureG, variably presented sequenced strains. The gene profiles strongly correlated distinct pathogenicity strains, strain harboring all five genes exhibiting highest fish. Phenotype assay confirmed that reduced decreased motility biofilm formation ability. Additionally, type VI secretion system, namely T6SS1, T6SS2, T6SS3, identified which can be classified six, four, subtypes, respectively. In conclusion, results indicated level mainly determined above may play vital roles environmental adaptation