Comparative genome analyses of Vibrio anguillarum strains reveal a link with pathogenicity traits

TY - JOUR

T1 - Comparative genome analyses of Vibrio anguillarum strains reveal a link with pathogenicity traits

AU - Castillo Bermúdez, Daniel Elías

AU - Alvise, Paul D.

AU - Xu, Ruiqi

AU - Zhang, Faxing

AU - Middelboe, Mathias

AU - Gram, Lone

PY - 2017/1/1

Y1 - 2017/1/1

N2 - Vibrio anguillarum is a marine bacterium that can cause vibriosis in many fish and shellfish species, leading to high mortalities and economic losses in aquaculture. Although putative virulence factors have been identified, the mechanism of pathogenesis of V. Anguillarum is not fully understood. Here, we analyzed wholegenome sequences of a collection of V. Anguillarum strains and compared them to virulence of the strains as determined in larval challenge assays. Previously identified virulence factors were globally distributed among the strains, with some genetic diversity. However, the pan-genome revealed that six out of nine high-virulence strains possessed a unique accessory genome that was attributed to pathogenic genomic islands, prophage-like elements, virulence factors, and a new set of gene clusters involved in biosynthesis, modification, and transport of polysaccharides. In contrast, V. Anguillarum strains that were medium to nonvirulent had a high degree of genomic homogeneity. Finally, we found that a phylogeny based on the core genomes clustered the strains with moderate to no virulence, while six out of nine high-virulence strains represented phylogenetically separate clusters. Hence, we suggest a link between genotype and virulence characteristics of Vibrio anguillarum, which can be used to unravel the molecular evolution of V. Anguillarum and can also be important from survey and diagnostic perspectives.

AB - Vibrio anguillarum is a marine bacterium that can cause vibriosis in many fish and shellfish species, leading to high mortalities and economic losses in aquaculture. Although putative virulence factors have been identified, the mechanism of pathogenesis of V. Anguillarum is not fully understood. Here, we analyzed wholegenome sequences of a collection of V. Anguillarum strains and compared them to virulence of the strains as determined in larval challenge assays. Previously identified virulence factors were globally distributed among the strains, with some genetic diversity. However, the pan-genome revealed that six out of nine high-virulence strains possessed a unique accessory genome that was attributed to pathogenic genomic islands, prophage-like elements, virulence factors, and a new set of gene clusters involved in biosynthesis, modification, and transport of polysaccharides. In contrast, V. Anguillarum strains that were medium to nonvirulent had a high degree of genomic homogeneity. Finally, we found that a phylogeny based on the core genomes clustered the strains with moderate to no virulence, while six out of nine high-virulence strains represented phylogenetically separate clusters. Hence, we suggest a link between genotype and virulence characteristics of Vibrio anguillarum, which can be used to unravel the molecular evolution of V. Anguillarum and can also be important from survey and diagnostic perspectives.

U2 - 10.1128/mSystems.00001-17

DO - 10.1128/mSystems.00001-17

M3 - Journal article

C2 - 28293680

SN - 2379-5077

VL - 2

JO - mSystems

JF - mSystems

IS - 1

M1 - e00001-17

ER -