Complete Genome Sequence Of Vibrio Anguillarum MVAV6203 And Comparative Genomics Analysis

Vibrio anguillarum is one of the most important fish pathogens causing the outbreaks of vibriosis in the wordwide of mariculture and our lab isolated a virulent strain V.anguillarum MVM425 from the perch in Shandong province.Because V.anguillarum could cause huge losses to mariculture,we pay more attention to virulence regulation of this species and vaccine exploitation to protect the Vibriosis.In our previous work,we have constructed a successful live attenuated vaccine V.anguillarum MVAV6203 via engineering the wild-type V.anguillarum MVM425 by gene deletion and plasmid curing,and this attenuated live vaccine could be administrated to marine fish(such as turbot)by simple immersion rout and evoke good immune protection against the challenge of wild-type V.anguillarum in Turbot.In this work,we sequenced the genome of V anguillarum MVAV6203 by 454,Illumina Solexa method and splicing of PCR.The genome of V.anguillarum MVAV6203,with the GC content of 44.5%,contains two chromosomes,the big one,termed as Chrl is 3,097,087 bp and contains 2838 genes,the small one,termed as Chr2 is approximately 950 kb and encodes about 1000 genes.Genome sequence analysis indicated that Chrl contains a number of the virulence related genes such as haemolysin,flagellin and out membrane protein.Most of the environmental adaptability genes like temperature stress,osmotic pressure and drug resistance are located on Chr2.V.anguillarum MVAV6203 chromosome 2 contains a super-integron with the length of about 60 kb and including 50～80 gene cassettes,most of the gene cassettes encode conservative hypothetical proteins.Several gene cassettes carry the genes related to Bleomycin resistance and RelBE Toxin-Antitoxin system which strengthen the stability of super-integron gene cassette array.Comparative genomics analysis demonstrated that V.anguillarum MVAV6203 has a close evolutionary relationship to Vibrio cholerae and Vibrio vulnificus,and simultaneously,its virulence regulation,pathogenic mechanism and drug resistance are similar to other vibrios strains.Comparative genomics analysis also determined 1895 important homologous proteins in vibrios.