Dataset Information

From cholera to corals: Viruses as drivers of virulence in a major coral bacterial pathogen.

ABSTRACT: Disease is an increasing threat to reef-building corals. One of the few identified pathogens of coral disease is the bacterium Vibrio coralliilyticus. In Vibrio cholerae, infection by a bacterial virus (bacteriophage) results in the conversion of non-pathogenic strains to pathogenic strains and this can lead to cholera pandemics. Pathogenicity islands encoded in the V. cholerae genome play an important role in pathogenesis. Here we analyse five whole genome sequences of V. coralliilyticus to examine whether virulence is similarly driven by horizontally acquired elements. We demonstrate that bacteriophage genomes encoding toxin genes with homology to those found in pathogenic V. cholerae are integrated in V. coralliilyticus genomes. Virulence factors located on chromosomal pathogenicity islands also exist in some strains of V. coralliilyticus. The presence of these genetic signatures indicates virulence in V. coralliilyticus is driven by prophages and other horizontally acquired elements. Screening for pathogens of coral disease should target conserved regions in these elements.

SUBMITTER: Weynberg KD

PROVIDER: S-EPMC4672265 | biostudies-literature | 2015 Dec

REPOSITORIES: biostudies-literature

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From cholera to corals: Viruses as drivers of virulence in a major coral bacterial pathogen.

Weynberg Karen D KD Voolstra Christian R CR Neave Matthew J MJ Buerger Patrick P van Oppen Madeleine J H MJ

Scientific reports 20151208

Disease is an increasing threat to reef-building corals. One of the few identified pathogens of coral disease is the bacterium Vibrio coralliilyticus. In Vibrio cholerae, infection by a bacterial virus (bacteriophage) results in the conversion of non-pathogenic strains to pathogenic strains and this can lead to cholera pandemics. Pathogenicity islands encoded in the V. cholerae genome play an important role in pathogenesis. Here we analyse five whole genome sequences of V. coralliilyticus to exa ...[more]

PMID: 26644037

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Project description:Chemotaxis, the directed movement toward or away from a chemical signal, can be essential to bacterial pathogens for locating hosts or avoiding hostile environments. The coral pathogen Vibrio coralliilyticus chemotaxes toward coral mucus; however, chemotaxis has not been experimentally demonstrated to be important for virulence. To further examine this, in-frame mutations were constructed in genes predicted to be important for V. coralliilyticus chemotaxis. Most Vibrio genomes contain multiple homologs of various chemotaxis-related genes, and two paralogs of each for cheB, cheR, and cheA were identified. Based on single mutant analyses, the paralogs cheB2, cheR2, and cheA1 were essential for chemotaxis in laboratory assays. As predicted, the ?cheA1 and ?cheR2 strains had a smooth-swimming pattern, while the ?cheB2 strain displayed a zigzag pattern when observed under light microscopy. However, these mutants, unlike the parent strain, were unable to chemotax toward the known attractants coral mucus, dimethylsulfoniopropionate, and N-acetyl-d-glucosamine. The ?cheB2 strain and an aflagellate ?fliG1 strain were avirulent to coral, while the ?cheA1 and ?cheR2 strains were hypervirulent (90 to 100% infection within 14 h on average) compared to the wild-type strain (66% infection within 36 h on average). Additionally, the ?cheA1 and ?cheR2 strains appeared to better colonize coral fragments than the wild-type strain. These results suggest that although chemotaxis may be involved with infection (the ?cheB2 strain was avirulent), a smooth-swimming phenotype is important for bacterial colonization and infection. This study provides valuable insight into understanding V. coralliilyticus pathogenesis and how this pathogen may be transmitted between hosts.IMPORTANCE Corals are responsible for creating the immense structures that are essential to reef ecosystems; unfortunately, pathogens like the bacterium Vibrio coralliilyticus can cause fatal infections of reef-building coral species. However, compared to related human pathogens, the mechanisms by which V. coralliilyticus initiates infections and locates new coral hosts are poorly understood. This study investigated the effects of chemotaxis, the directional swimming in response to chemical signals, and bacterial swimming patterns on infection of the coral Montipora capitata Infection experiments with different mutant strains suggested that a smooth-swimming pattern resulted in hypervirulence. These results demonstrate that the role of chemotaxis in coral infection may not be as straightforward as previously hypothesized and provide valuable insight into V. coralliilyticus pathogenesis.

Dataset Information

From cholera to corals: Viruses as drivers of virulence in a major coral bacterial pathogen.

Publications

From cholera to corals: Viruses as drivers of virulence in a major coral bacterial pathogen.

Similar Datasets

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