Comparative Genomic And Transcriptomic Analysis Of Two Strains Of Vibrio Anguillarum

Vibrio anguillarum is a Gram-negative Gammaproteobacteria and can cause epidemic vibriosis in fish, bivalves and crustaceans, with the character as a hemorrhage septicemia to beget enormous economic losses. Whole genome sequencing of Vibrio anguillarum clinical pathogenic strain M3 and nonpathogenic ATCC43308 were perfomed with a combined strategy of using Roche 454 GS(FLX Titanium) pyrosequencing and AB SOLID mate-paired sequencing technology. In addition, based on the genomic information, transcriptomic profilings of M3 and ATCC43308 were analyzed by RNA-Seq tech. The sequence analysis of genome and transcriptome provided molecular-level understanding of genetic information and pathogenicity about Vibrio anguillarum.Pathogenic M3 was made of 23 scaffolds, with the length of N50 with 240.6 kb, the content of G+C% with 44.5%, the amount of predicted and annotated CDS with 4009 and the average length of CDS with 295aa, with 48 tRNAs and 3 16s-23s-5s rRNAs. For nonpathgenic ATCC43308 with 15 scaffolds, the length of N50 334.6 kb, the G+C% 44.4%, CDS with 3820, the average length of CDS with 293aa, 49 tRNAs and 3 16s-23s-5s rRNAs. 27% of CDS participated in the metabolism, transport and replicate, transcription regulation et al. Some(about 10% CDS)were responsible for the pathogenesis containing secretion, adhesin and pilus et al.Comparative genomics analysis among M3, ATCC43308 and other related available species described the detailed characteristics of the metabolism mechanism and pathogenesis about V. anguillarum. The strain ATCC43308 lacked a gene cluster, wza-wzb-wzc, which is responsible for the capsular polysaccharides transport through the cell membrane. Compared to ATCC43308, M3 were larger about 230 kb in genome seize, more 190 CDS in amount. The differences mainly pooled in the aspects including signal transduct, enzyme metabolism, cell envelope biogenesis and function unkown. For M3 and ATCC43308, more new hemolysin,metalloprotease and T6SS-related genes were found, some of which respected to the virulence of pathogen. Furthermore, compared to ATCC43308, more exterior sequences such as IS (28 vs 14) ,Tn(21 vs 19)and prophag(e18 vs 9), some of which are proved to be activators of other genes, were found in M3. We speculated that the components were necessary for M3 to cause diseases.Comparative transcriptomic analysis of the two strains revealed 191 genes whose expression level differentiated remarkably.Many methods were perfomed to detect the pathogen, such as real time PCR, immunoprobe and serological reaction. Based on the genome sequences of the two-component system toxR-toxS of genus Vibrio, six pairs of conserved primers to simultaneously detect main pathogenic vibrio including V. anguillarum, V. alginolyticus, V. harveyi, V. parahaemolyticus, V. vulnificus and V. cholerae were designed. The results showed that multiplex PCR have fairly specific to Vibrio, and nonspecific and cross-reaction were not found. Reaction sensitivity was 10~100 CFU. The detection for real samples also proved its reliability.