Identification ofVibrio alginolyticusvirulent strain-specific DNA regions by suppression subtractive hybridization and PCR

Aims Vibrio alginolyticuswas frequently isolated from diseased farmed fish in the coaster waters of Hainan Island over the past two decades. In this study, we attempted to identify candidates of virulent strain-specific DNA regions for this pathogen. Methods and Results Suppression subtractive hybridization (SSH) and PCR were successively performed between the typical virulent strain and avirulent strain ofV. alginolyticus, in which they shared 99 center dot 54% homology of 16S rDNAs. Out of 2873 subtracted clones, nine clones were finally indicated to harbour virulent strain-specific DNA fragments. The receivable functions of the major fragments in the nine clones were believed to encode methyl-accepting chemotaxis protein (n = 1), type VI secretion system-associated FHA domain protein TagH (n = 1), diguanylate cyclase (n = 1), AraC family transcriptional regulator(n = 1), ABC-type uncharacterized transport system permease component (n = 1) and hypothetical proteins (n = 4). Two hypothetical proteins contain several disordered regions. Conclusions Some specific DNA regions existed in the virulent strain ofV. alginolyticus, and the SSH assay could be a highly sensitive method for identifying virulent regions in pathogens. Significance and Impact of the Study This report is the first to describe the identification of virulent strain-specific DNA regions in theV. alginolyticusgenome, which is helpful in developing virulent strain-specific rapid detection methods and is a pivotal precondition for clarifying the molecular virulence mechanism ofV. alginolyticus.