Characterization of geographically distinct bacterial communities associated with coral mucus produced by Acropora spp. and Porites spp.

Department of Biological Sciences, University of Essex, Wivenhoe Park, Colchester, Essex, United Kingdom.
Applied and Environmental Microbiology (Impact Factor: 3.95). 05/2012; 78(15):5229-37. DOI: 10.1128/AEM.07764-11
Source: PubMed

ABSTRACT Acropora and Porites corals are important reef builders in the Indo-Pacific and Caribbean. Bacteria associated with mucus produced by Porites spp. and Acropora spp. from Caribbean (Punta Maroma, Mexico) and Indo-Pacific (Hoga and Sampela, Indonesia) reefs were determined. Analysis of pyrosequencing libraries showed that bacterial communities from Caribbean corals were significantly more diverse (H', 3.18 to 4.25) than their Indonesian counterparts (H', 2.54 to 3.25). Dominant taxa were Gammaproteobacteria, Alphaproteobacteria, Firmicutes, and Cyanobacteria, which varied in relative abundance between coral genera and region. Distinct coral host-specific communities were also found; for example, Clostridiales were dominant on Acropora spp. (at Hoga and the Mexican Caribbean) compared to Porites spp. and seawater. Within the Gammproteobacteria, Halomonas spp. dominated sequence libraries from Porites spp. (49%) and Acropora spp. (5.6%) from the Mexican Caribbean, compared to the corresponding Indonesian coral libraries (<2%). Interestingly, with the exception of Porites spp. from the Mexican Caribbean, there was also a ubiquity of Psychrobacter spp., which dominated Acropora and Porites libraries from Indonesia and Acropora libraries from the Caribbean. In conclusion, there was a dominance of Halomonas spp. (associated with Acropora and Porites [Mexican Caribbean]), Firmicutes (associated with Acropora [Mexican Caribbean] and with Acropora and Porites [Hoga]), and Cyanobacteria (associated with Acropora and Porites [Hoga] and Porites [Sampela]). This is also the first report describing geographically distinct Psychrobacter spp. associated with coral mucus. In addition, the predominance of Clostridiales associated with Acropora spp. provided additional evidence for coral host-specific microorganisms.

  • [Show abstract] [Hide abstract]
    ABSTRACT: Diazotrophic bacteria potentially play an important functional role in supplying fixed nitrogen to the coral holobiont, but the value of such a partnership depends on the stability of the association. Here we evaluate the composition of diazotroph assemblages associated with the coral Acropora millepora, throughout four seasons and at two reefs, an inshore and an offshore (mid-shelf) reef on the Great Barrier Reef, Australia. Amplicon pyrosequencing of the nifH gene revealed that diazotrophs are ubiquitous members of the bacterial community associated with A. millepora. Rhizobia (65% of the overall nifH sequences retrieved) and particularly Bradyrhizobia sp.-affiliated sequences (>50% of rhizobia sequences), dominated diazotrophic assemblages across all coral samples from the two sites throughout the year. In contrast to this consistency in the spatial and temporal patterns of occurrence of diazotroph assemblages, the overall coral-associated bacterial community, assessed through amplicon sequencing of the general bacterial 16S rRNA gene, differed between inshore and mid-shelf reef locations. Sequences associated with the Oceanospirillales family, particularly with Endozoicomonas sp., dominated bacterial communities associated with inshore corals. Although rhizobia represented a variable and generally small fraction of the overall bacterial community associated with Acropora millepora, consistency in the structure of these diazotrophic assemblages suggests they have a functional role in the coral holobiont.
    Environmental Microbiology 12/2013; · 6.24 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Bacteria living within the surface mucus layer of corals compete for nutrients and space. A number of stresses affect the outcome of this competition. The interactions between native microorganisms and opportunistic pathogens largely determine the coral holobiont's overall health and fitness. In this study, we tested the hypothesis that commensal bacteria isolated from the mucus layer of a healthy elkhorn coral, Acropora palmata, are capable of inhibition of opportunistic pathogens, Vibrio shiloi AK1 and Vibrio coralliilyticus. These vibrios are known to cause disease in corals and their virulence is temperature dependent. Elevated temperature (30 °C) increased the cell numbers of one commensal and both Vibrio pathogens in monocultures. We further tested the hypothesis that elevated temperature favors pathogenic organisms by simultaneously increasing the fitness of vibrios and decreasing the fitness of commensals by measuring growth of each species within a co-culture over the course of 1 week. In competition experiments between vibrios and commensals, the proportion of Vibrio spp. increased significantly under elevated temperature. We finished by investigating several temperature-dependent mechanisms that could influence co-culture differences via changes in competitive fitness. The ability of Vibrio spp. to utilize glycoproteins found in A. palmata mucus increased or remained stable when exposed to elevated temperature, while commensals' tended to decrease utilization. In both vibrios and commensals, protease activity increased at 30 °C, while chiA expression increased under elevated temperatures for Vibrio spp. These results provide insight into potential mechanisms through which elevated temperature may select for pathogenic bacterial dominance and lead to disease or a decrease in coral fitness.
    Microbial Ecology 12/2013; · 3.12 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Diverse sessile organisms inhabit the coral reef ecosystems, including corals, sponges, and sea anemones. In the past decades, scleractinian corals (Cnidaria, Anthozoa, Scleractinia) and their associated microorganisms have attracted much attention. Zoanthids (Cnidaria, Anthozoa, Zoanthidea) are commonly found in coral reefs. However, little is known about the community structure of zoanthid-associated microbiota. In this study, the microbial community associated with the zoanthid Palythoa australiae in the South China Sea was investigated by 454 pyrosequencing. As a result, 2,353 bacterial, 583 archaeal, and 36 eukaryotic microbial ribotypes were detected, respectively. A total of 22 bacterial phyla (16 formally described phyla and six candidate phyla) were recovered. Proteobacteria was the most abundant group, followed by Chloroflexi and Actinobacteria. High-abundance Rhizobiales and diverse Chloroflexi were observed in the bacterial community. The archaeal population was composed of Crenarchaeota and Euryarchaeota, with Marine Group I as the dominant lineage. In particular, Candidatus Nitrosopumilus dominated the archaeal community. Besides bacteria and archaea, the zoanthid harbored eukaryotic microorganisms including fungi and algae though their diversity was very low. This study provided the first insights into the microbial community associated with P. australiae by 454 pyrosequencing, consequently laid a basis for the understanding of the association of P. australiae-microbes symbioses.
    Microbial Ecology 02/2014; · 3.12 Impact Factor

Full-text (2 Sources)

Available from
Jun 10, 2014