Genetic bases of immunity and disease resistance to white band disease in the Caribbean staghorn coral Acropora cervicornis

Determining the adaptive potential of foundation species, such as reef-building corals, is urgent as the oceans warm and coral populations decline. Theory predicts that corals may adapt to climate change via selection on standing genetic variation. Yet, corals face not only rising temperatures but also novel diseases. We studied the interaction between two major stressors affecting colonies of the threatened coral, Acropora cervicornis: white-band disease and high water temperature. We determined that 27% of A. cervicornis were disease resistant prior to a thermal anomaly. However, disease resistance was largely lost during a bleaching event because of more compromised coral hosts or increased pathogenic dose/virulence. There was no tradeoff between disease resistance and temperature tolerance; disease susceptibility was independent of Symbiodinium strain. The present study shows that susceptibility to temperature stress creates an increased risk in disease-associated mortality, and only rare genets may maintain or gain infectious disease resistance under high temperature. We conclude that A. cervicornis populations in the lower Florida Keys harbor few existing genotypes that are resistant to both warming and disease.

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Tissue mortality by Caribbean ciliate infection and white band disease in three reef-building coral species

PeerJ ◽

10.7717/peerj.2196 ◽

2016 ◽

Vol 4 ◽

pp. e2196 ◽

Cited By ~ 4

Author(s):

Alejandra Verde ◽

Carolina Bastidas ◽

Aldo Croquer

Keyword(s):

Coral Species ◽

Coral Cover ◽

Mortality Rates ◽

Tissue Loss ◽

Coral Tissue ◽

Acropora Cervicornis ◽

White Band ◽

Orbicella Faveolata ◽

The Caribbean ◽

White Band Disease

Caribbean ciliate infection (CCI) and white band disease (WBD) are diseases that affect a multitude of coral hosts and are associated with rapid rates of tissue losses, thus contributing to declining coral cover in Caribbean reefs. In this study we compared tissue mortality rates associated to CCI in three species of corals with different growth forms:Orbicella faveolata(massive-boulder),O. annularis(massive-columnar) andAcropora cervicornis(branching). We also compared mortality rates in colonies ofA. cervicornisbearing WBD and CCI. The study was conducted at two locations in Los Roques Archipelago National Park between April 2012 and March 2013. InA. cervicornis, the rate of tissue loss was similar between WBD (0.8 ± 1 mm/day, mean ± SD) and CCI (0.7 ± 0.9 mm/day). However, mortality rate by CCI inA. cervicorniswas faster than in the massive speciesO. faveolata(0.5 ± 0.6 mm/day) andO. annularis(0.3 ± 0.3 mm/day). Tissue regeneration was at least fifteen times slower than the mortality rates for both diseases regardless of coral species. This is the first study providing coral tissue mortality and regeneration rates associated to CCI in colonies with massive morphologies, and it highlights the risks of further cover losses of the three most important reef-building species in the Caribbean.

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

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2014.0094 ◽

2014 ◽

Vol 281 (1788) ◽

pp. 20140094 ◽

Cited By ~ 39

Author(s):

M. J. Sweet ◽

A. Croquer ◽

J. C. Bythell

Keyword(s):

Coral Disease ◽

Causal Agent ◽

Acropora Palmata ◽

Acropora Cervicornis ◽

Coral Diseases ◽

White Band ◽

Disease Causation ◽

Community Shifts ◽

White Band Disease ◽

Experimental Treatments

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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Evidence for Autoinduction and Quorum Sensing in White Band Disease-Causing Microbes on Acropora cervicornis

Scientific Reports ◽

10.1038/srep11134 ◽

2015 ◽

Vol 5 (1) ◽

Cited By ~ 17

Author(s):

Rebecca H. Certner ◽

Steven V. Vollmer

Keyword(s):

Quorum Sensing ◽

Acropora Cervicornis ◽

White Band ◽

White Band Disease

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RNA-seq Profiles of Immune Related Genes in the Staghorn Coral Acropora cervicornis Infected with White Band Disease

PLoS ONE ◽

10.1371/journal.pone.0081821 ◽

2013 ◽

Vol 8 (11) ◽

pp. e81821 ◽

Cited By ~ 72

Author(s):

Silvia Libro ◽

Stefan T. Kaluziak ◽

Steven V. Vollmer

Keyword(s):

Acropora Cervicornis ◽

Rna Seq ◽

White Band ◽

White Band Disease ◽

Immune Related Genes

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Zooplankton as a potential vector for white band disease transmission in the endangered coral,Acropora cervicornis

PeerJ ◽

10.7717/peerj.3502 ◽

2017 ◽

Vol 5 ◽

pp. e3502 ◽

Cited By ~ 5

Author(s):

Rebecca H. Certner ◽

Amanda M. Dwyer ◽

Mark R. Patterson ◽

Steven V. Vollmer

Keyword(s):

Disease Transmission ◽

Coral Disease ◽

Acropora Cervicornis ◽

Experimental Conditions ◽

Bocas Del Toro ◽

White Band ◽

Tissue Homogenates ◽

Potential Mode ◽

White Band Disease ◽

Zooplankton Communities

Coral diseases are a leading factor contributing to the global decline of coral reefs, and yet mechanisms of disease transmission remain poorly understood. This study tested whether zooplankton can act as a vector for white band disease (WBD) inAcropora cervicornis. Natural zooplankton communities were collected from a coral reef in Bocas del Toro, Panama. Half of the zooplankton were treated with antibiotics for 24 h after which the antibiotic-treated and non-antibiotic-treated zooplankton were incubated with either seawater or tissue homogenates from corals exhibiting WBD-like symptoms. A total of 15 of the 30 asymptomaticA. cervicorniscolonies exposed to zooplankton incubated in disease homogenate in tank-based experiments showed signs of WBD, regardless of prior antibiotic incubation. These results indicate that in our experimental conditions zooplankton were a vector for coral disease after exposure to disease-causing pathogens. Given the importance of heterotrophy on zooplankton to coral nutrition, this potential mode of disease transmission warrants further investigation.

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