Diversity and pathogenic potential of vibrios isolated from Abrolhos Bank corals

Abstract

We performed the first taxonomic characterization of vibrios and other culturable microbiota from apparently healthy and diseased Brazilian-endemic corals at the Abrolhos reef bank. The diseases affecting corals were tissue necrosis in Phyllogorgia dillatata, white plague and bleaching in Mussismilia braziliensis and bleaching in Mussismilia hispida. Bacterial isolates were obtained from mucus of 22 coral specimens originated from the Abrolhos Bank (i.e. Itacolomis reef, Recife de Fora reef and Santa Barbara Island) in 2007. Vibrios counts in the water and coral mucus were approximately 104 cfu ml(-1) and 106 cfu ml(-1) respectively. One hundred and thirty-one representative vibrio isolates were identified. Most vibrio isolates (n = 79) fell into the core group using the pyrH identification marker. According to our analysis, diseased corals did not possess a unique vibrio microbiota. Vibrio species encompassed strains originated from both apparently healthy and diseased corals. The pathogenic potential of representative vibrio isolates (V. alginolyticus 40B, V. harveyi-like 1DA3 and V. coralliilyticus 2DA3) were evaluated in a standardized bioassay using the animal model Drosophila melanogaster and caused 25-88% mortality. This is the first taxonomic characterization of the culturable microbiota from the Brazilian-endemic corals. Endemic Brazilian corals are a reservoir of the vibrio core group. Vibrio alginolyticus, V. harveyi and V. coralliilyticus are dominant in the mucus of these corals and may be a normal component of the holobiont.

Genomic and proteomic analyses of the coral pathogen Vibrio coralliilyticus reveal a diverse virulence repertoire

“…Recent work has shown that vibrios, including V. coralliilyticus, are ubiquitous in coral mucus (Chimetto et al, 2008;Alves et al, 2010) and often dominate the microbial community of diseased corals (Bourne and Munn, 2005;Luna et al, 2007). A similar pattern is observed at the whole reef scale as vibrios have been demonstrated to have much higher loads on unhealthy vs healthy coral reefs (Dinsdale et al, 2008).…”

“…Drosophila assays were performed as described by Alves et al (2010). In brief, 10 wild-type Canton-S adult flies were placed in vials containing a cotton plug saturated with tryptone soy broth either alone or inoculated with 10 8 colony-forming units per ml of V. coralliilyticus strain P1 wild-type or mutant cells (Blow et al, 2005).…”

Temperature regulation of virulence factors in the pathogen Vibrio coralliilyticus

“…Although it is uncertain whether V. coralliilyticus is a primary or opportunistic coral pathogen, evidence strongly suggests that this endemic member of global coral holobionts (Pollock et al, 2010) has a role in coral disease (Rosenberg and Kushmaro, 2011). Infection experiments establish the ability of V. coralliilyticus to cause bacterial bleaching (Ben-Haim et al, 2003b), white syndrome (Sussman et al, 2008) and mortality in corals (Alves et al, 2010;Vezzulli et al, 2010), in addition to being associated with the microbial consortium of black band disease (Arotsker et al, 2009). V. coralliilyticus type strain ATCC (American Type Culture Collection, Manassas, VA, USA) BAA-450 (Vc450), isolated from bleached corals near Zanzibar, displays a tightly regulated temperature-dependent virulence; it is capable of invading and lysing coral tissue of Pocillopora damicornis at temperatures 427 1C, it attacks the symbiotic algae of this coral at temperatures between 24 1C and 26.5 1C and is avirulent at temperatures p24 1C (Ben-Haim et al, 2003b).…”

“…In addition, we use two-dimensional liquid chromatography coupled with tandem mass spectrometry and bioassays to investigate the influence of nonpathogenic (24 1C) and pathogenic (27 1C) temperatures on the expression of virulence Figure 1 Global distribution of V. coralliilyticus strains. The V. coralliilyticus strains represented here are (a) type strains (Ben-Haim et al, 2003a), as well as strains identified using (b) DnaJ PCR (Vezzulli et al, 2010), (c, d) 16S rRNA sequencing (Sussman et al, 2008;Kesarcodi-Watson et al, 2009), (e) multi-locus sequencing (Alves et al, 2010) and (f) multiple molecular analyzes, that is, 16S rRNA sequencing, recA PCR and repetitive extragenic palindromic -polymerase chain reaction (REP-PCR) (Vizcaino et al, 2010).…”

“…V. coralliilyticus has been isolated from marine organisms in the Atlantic (Ben-Haim et al, 2003a;Alves et al, 2010;Vizcaino et al, 2010), Indian (Ben-Haim et al, 2003a) and Pacific Oceans (Sussman et al, 2008;Kesarcodi-Watson et al, 2009), as well as the Mediterranean (Vezzulli et al, 2010) and Red Seas (Ben-Haim et al, 2003a) (Figure 1). It causes fatal infections in a wide range of organisms, including unicellular algae (Ben-Haim et al, 2003b;de Oliveira Santos et al, 2011), corals (Ben-Haim et al, 2003b), oysters (Jeffries, 1982), shrimp (Austin et al, 2005;de Oliveira Santos et al, 2011), rainbow trout (Austin et al, 2005) and flies (Alves et al, 2010;de Oliveira Santos et al, 2011) during experimental infection assays. Although it is uncertain whether V. coralliilyticus is a primary or opportunistic coral pathogen, evidence strongly suggests that this endemic member of global coral holobionts (Pollock et al, 2010) has a role in coral disease (Rosenberg and Kushmaro, 2011).…”