Widespread association of a <i>Rickettsiales</i>‐like bacterium with reef‐building corals

Casas, Veronica; Kline, David I.; Wegley, Linda; Yu, Yanan; Breitbart, Mya; Rohwer, Forest

doi:10.1111/j.1462-2920.2004.00647.x

Cited by 85 publications

(79 citation statements)

References 36 publications

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“…are globally associated with several coral diseases (e.g., black band, white plague, and white band disease) and two destructive conditions (atramentous necrosis and cyanobacterial patches) (53). There is also a suggested link between Rickettsia-like bacteria and marine diseases afflicting invertebrates such as corals and abalone (1,13). These results support our field observations that the M. faveolata colonies selected for sampling were generally healthy and unaffected by disease but that the St. Thomas and Florida Keys corals likely experienced greater levels of environmental stress and/or anthropogenic microbial influx.…”

Section: Discussionmentioning

confidence: 99%

Bacterial Associates of Two Caribbean Coral Species Reveal Species-Specific Distribution and Geographic Variability

Morrow

Moss

Chadwick

et al. 2012

Appl Environ Microbiol

203

158

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ABSTRACTScleractinian corals harbor microorganisms that form dynamic associations with the coral host and exhibit substantial genetic and ecological diversity. Microbial associates may provide defense against pathogens and serve as bioindicators of changing environmental conditions. Here we describe the bacterial assemblages associated with two of the most common and phylogenetically divergent reef-building corals in the Caribbean,Montastraea faveolataandPorites astreoides. Contrasting life history strategies and disease susceptibilities indicate potential differences in their microbiota and immune function that may in part drive changes in the composition of coral reef communities. The ribotype structure and diversity of coral-associated bacteria within the surface mucosal layer (SML) of healthy corals were assessed using denaturing gradient gel electrophoresis (DGGE) fingerprinting and 454 bar-coded pyrosequencing. Corals were sampled at disparate Caribbean locations representing various levels of anthropogenic impact. We demonstrate here thatM. faveolataandP. astreoidesharbor distinct, host-specific bacteria but that specificity varies by species and site.P. astreoidesgenerally hosts a bacterial assemblage of low diversity that is largely dominated by one bacterial genus,Endozoicomonas, within the orderOceanospirillales. The bacterial assemblages associated withM. faveolataare significantly more diverse and exhibit higher specificity at the family level thanP. astreoidesassemblages. Both corals have more bacterial diversity and higher abundances of disease-related bacteria at sites closer to the mainland than at those furthest away. The most diverse bacterial taxa and highest relative abundance of disease-associated bacteria were seen for corals near St. Thomas, U.S. Virgin Islands (USVI) (2.5 km from shore), and the least diverse taxa and lowest relative abundance were seen for corals near our most pristine site in Belize (20 km from shore). We conclude that the two coral species studied harbor distinct bacterial assemblages within the SML, but the degree to which each species maintains specific microbial associations varies both within each site and across large spatial scales. The taxonomic scale (i.e., phylum versus genus) at which scientists examine coral-microbe associations, in addition to host-elicited factors and environmental fluctuations, must be considered carefully in future studies of the coral holobiont.

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Section: Discussionmentioning

confidence: 99%

Bacterial Associates of Two Caribbean Coral Species Reveal Species-Specific Distribution and Geographic Variability

Morrow

Moss

Chadwick

et al. 2012

Appl Environ Microbiol

203

158

View full text Add to dashboard Cite

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“…Semi-quantitative data (Jagoe, 1996) were collected from each subsample based on relative condition (tissue architecture, cellular integrity, zooxanthellae abundance, pathological changes) at the time of fixation (0 = Excellent, 1 = Very Good, 2 = Good, 3 = Fair, 4 = Poor, 5 = Very Poor) and severity or intensity of tissue changes from normal (0 = Within Normal Limits, 1 = Minimal, 2 = Mild, 3 = Moderate, 4 = Marked, 5 = Severe) (see Table S1). Histoslides of A. cervicornis and A. palmata collected from the 1970s in the Florida Keys (the earliest tissue samples located, before tissue loss was reported from this region) were used to develop the “within normal limits” criteria for general coral tissue condition and zooxanthellae condition/abundance scores, six specific cell or tissue parameters of polyp health, bacterial aggregates (Peters, Oprandy & Yevich, 1983), and suspect rickettsia-like organisms (RLOs) (Casas et al, 2004; CS Friedman, pers. comm., 2010).…”

Section: Methodsmentioning

confidence: 99%

Disease dynamics and potential mitigation among restored and wild staghorn coral,Acropora cervicornis

Miller

Lohr

Cameron

et al. 2014

PeerJ

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The threatened status (both ecologically and legally) of Caribbean staghorn coral, Acropora cervicornis, has prompted rapidly expanding efforts in culture and restocking, although tissue loss diseases continue to affect populations. In this study, disease surveillance and histopathological characterization were used to compare disease dynamics and conditions in both restored and extant wild populations. Disease had devastating effects on both wild and restored populations, but dynamics were highly variable and appeared to be site-specific with no significant differences in disease prevalence between wild versus restored sites. A subset of 20 haphazardly selected colonies at each site observed over a four-month period revealed widely varying disease incidence, although not between restored and wild sites, and a case fatality rate of 8%. A tropical storm was the only discernable environmental trigger associated with a consistent spike in incidence across all sites. Lastly, two field mitigation techniques, (1) excision of apparently healthy branch tips from a diseased colony, and (2) placement of a band of epoxy fully enclosing the diseased margin, gave equivocal results with no significant benefit detected for either treatment compared to controls. Tissue condition of associated samples was fair to very poor; unsuccessful mitigation treatment samples had severe degeneration of mesenterial filament cnidoglandular bands. Polyp mucocytes in all samples were infected with suspect rickettsia-like organisms; however, no bacterial aggregates were found. No histological differences were found between disease lesions with gross signs fitting literature descriptions of white-band disease (WBD) and rapid tissue loss (RTL). Overall, our results do not support differing disease quality, quantity, dynamics, nor health management strategies between restored and wild colonies of A. cervicornis in the Florida Keys.

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“…These were similar to a group of bacteria previously detected exclusively in diseased tissues of other coral diseases (white plague and black band disease). By contrast, Casas et al [13] failed to detect any specific pathogens in WBD using culture-independent techniques and suggested that there might be a non-pathogenic cause of this disease. However, recently, a study by Kline & Vollmer [14] used homogenates of diseased tissue to demonstrate that WBD is, in fact, a transmissible disease attributable to a 0.22–0.45 µm filterable fraction that was susceptible to antibiotic treatment.…”

Section: Introductionmentioning

confidence: 99%

Experimental antibiotic treatment identifies potential pathogens of white band disease in the endangered Caribbean coral Acropora cervicornis

2014

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Coral diseases have been increasingly reported over the past few decades and are a major contributor to coral decline worldwide. The Caribbean, in particular, has been noted as a hotspot for coral disease, and the aptly named white syndromes have caused the decline of the dominant reef building corals throughout their range. White band disease (WBD) has been implicated in the dramatic loss of Acropora cervicornis and Acropora palmata since the 1970s, resulting in both species being listed as critically endangered on the International Union for Conservation of Nature Red list. The causal agent of WBD remains unknown, although recent studies based on challenge experiments with filtrate from infected hosts concluded that the disease is probably caused by bacteria. Here, we report an experiment using four different antibiotic treatments, targeting different members of the disease-associated microbial community. Two antibiotics, ampicillin and paromomycin, arrested the disease completely, and by comparing with community shifts brought about by treatments that did not arrest the disease, we have identified the likely candidate causal agent or agents of WBD. Our interpretation of the experimental treatments is that one or a combination of up to three specific bacterial types, detected consistently in diseased corals but not detectable in healthy corals, are likely causal agents of WBD. In addition, a histophagous ciliate (Philaster lucinda) identical to that found consistently in association with white syndrome in Indo-Pacific acroporas was also consistently detected in all WBD samples and absent in healthy coral. Treatment with metronidazole reduced it to below detection limits, but did not arrest the disease. However, the microscopic disease signs changed, suggesting a secondary role in disease causation for this ciliate. In future studies to identify a causal agent of WBD via tests of Henle–Koch's postulates, it will be vital to experimentally control for populations of the other potential pathogens identified in this study.

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Widespread association of a Rickettsiales‐like bacterium with reef‐building corals

Abstract: SummaryWhiite band disease type I (WBD I) has been a major cause of thie dramatic deciine of Acroporid corai popuiations thiroughout the Caribbean during the iast two decades, yet the aetioiogicai agent of this disease is unl Show more

Cited by 85 publications

References 36 publications

Bacterial Associates of Two Caribbean Coral Species Reveal Species-Specific Distribution and Geographic Variability

Bacterial Associates of Two Caribbean Coral Species Reveal Species-Specific Distribution and Geographic Variability

Disease dynamics and potential mitigation among restored and wild staghorn coral,Acropora cervicornis

Experimental antibiotic treatment identifies potential pathogens of white band disease in the endangered Caribbean coral Acropora cervicornis

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