scholarly journals Viral-Like Particles Are Associated With Endosymbiont Pathology in Florida Corals Affected by Stony Coral Tissue Loss Disease

2021 ◽  
Vol 8 ◽  
Author(s):  
Thierry M. Work ◽  
Tina M. Weatherby ◽  
Jan H. Landsberg ◽  
Yasunari Kiryu ◽  
Samantha M. Cook ◽  
...  
Keyword(s):  
Host Cell ◽  
Viral Disease ◽  
Host Cells ◽  
Tissue Loss ◽  
Coral Tissue ◽  
Coral Host ◽  
Stony Coral ◽  
Mucus Cells ◽  
Functional Extinction ◽  
Apparently Healthy

Stony coral tissue loss disease (SCTLD) was first documented in 2014 near the Port of Miami, Florida, and has since spread north and south along Florida’s Coral Reef, killing large numbers of more than 20 species of coral and leading to the functional extinction of at least one species, Dendrogyra cylindrus. SCTLD is assumed to be caused by bacteria based on presence of different molecular assemblages of bacteria in lesioned compared to apparently healthy tissues, its apparent spread among colonies, and cessation of spread of lesions in individual colonies treated with antibiotics. However, light microscopic examination of tissues of corals affected with SCTLD has not shown bacteria associated with tissue death. Rather, microscopy shows dead and dying coral cells and symbiotic dinoflagellates (endosymbionts) indicating a breakdown of host cell and endosymbiont symbiosis. It is unclear whether host cells die first leading to death of endosymbionts or vice versa. Based on microscopy, hypotheses as to possible causes of SCTLD include infectious agents not visible at the light microscopy level or toxicosis, perhaps originating from endosymbionts. To clarify this, we examined corals affected with SCTLD and apparently healthy corals using transmission electron microscopy. Endosymbionts in SCTLD-affected and apparently healthy corals consistently had varying degrees of pathology associated with elongated particles compatible in morphology with filamentous positive single-stranded RNA viruses of plants termed anisometric viral-like particles (AVLP). There was apparent progression from early to late replication of AVLP in the cytoplasm of endosymbionts adjacent to or at times within chloroplasts, with morphologic changes in chloroplasts consistent with those seen in plant cells infected by viruses. Coral host cell pathology appeared limited to massive proliferation and lysis of mucus cells. Based on these findings, we hypothesize that SCTLD is a viral disease of endosymbionts leading to coral host death. Efforts to confirm the presence of a virus associated with SCTLD through other means would be appropriate. These include showing the presence of a virus through molecular assays such as deep sequencing, attempts to grow this virus in the laboratory through culture of endosymbionts, localization of virus in tissue sections using immunohistochemistry or in situ hybridization, and experimental infection of known-virus-negative corals to replicate disease at the gross and microscopic level.

scholarly journals Stony Coral Tissue Loss Disease in Florida Is Associated With Disruption of Host–Zooxanthellae Physiology

2020 ◽  
Vol 7 ◽  
Author(s):  
Jan H. Landsberg ◽  
Yasunari Kiryu ◽  
Esther C. Peters ◽  
Patrick W. Wilson ◽  
Noretta Perry ◽  
...  
Keyword(s):  
Body Wall ◽  
Chromatin Condensation ◽  
Periodic Acid ◽  
Clinical Signs ◽  
Host Cells ◽  
Tissue Loss ◽  
Coral Tissue ◽  
Crystalline Inclusion ◽  
Periodic Acid Schiff ◽  
Stony Coral

Samples from eight species of corals (Colpophyllia natans, Dendrogyra cylindrus, Diploria labyrinthiformis, Meandrina meandrites, Montastraea cavernosa, Orbicella faveolata, Pseudodiploria strigosa, and Siderastrea siderea) that exhibited gross clinical signs of acute, subacute, or chronic tissue loss attributed to stony coral tissue loss disease (SCTLD) were collected from the Florida Reef Tract during 2016–2018 and examined histopathologically. The hallmark microscopic lesion seen in all eight species was focal to multifocal lytic necrosis (LN) originating in the gastrodermis of the basal body wall (BBW) and extending to the calicodermis, with more advanced lesions involving the surface body wall. This was accompanied by other degenerative changes in host cells such as mucocyte hypertrophy, degradation and fragmentation of gastrodermal architecture, and disintegration of the mesoglea. Zooxanthellae manifested various changes including necrosis (cytoplasmic hypereosinophilia, pyknosis); peripheral nuclear chromatin condensation; cytoplasmic vacuolation accompanied by deformation, swelling, or atrophy; swollen accumulation bodies; prominent pyrenoids; and degraded chloroplasts. Polyhedral intracytoplasmic eosinophilic periodic acid–Schiff-positive crystalline inclusion bodies (∼1–10 μm in length) were seen only in M. cavernosa and P. strigosa BBW gastrodermis in or adjacent to active lesions and some unaffected areas (without surface lesions) of diseased colonies. Coccoidlike or coccobacilloidlike structures (Gram-neutral) reminiscent of microorganisms were occasionally associated with LN lesions or seen in apparently healthy tissue of diseased colonies along with various parasites and other bacteria all considered likely secondary colonizers. Of the 82 samples showing gross lesions of SCTLD, 71 (87%) were confirmed histologically to have LN. Collectively, pathology indicates that SCTLD is the result of a disruption of host–symbiont physiology with lesions originating in the BBW leading to detachment and sloughing of tissues from the skeleton. Future investigations could focus on identifying the cause and pathogenesis of this process.

scholarly journals Metabolomics of Healthy and Stony Coral Tissue Loss Disease Affected Montastraea cavernosa Corals

2021 ◽  
Vol 8 ◽  
Author(s):  
Jessica M. Deutsch ◽  
Olakunle A. Jaiyesimi ◽  
Kelly A. Pitts ◽  
Jay Houk ◽  
Blake Ushijima ◽  
...  
Keyword(s):  
Coral Species ◽  
Principal Component ◽  
Tissue Loss ◽  
Coral Tissue ◽  
Metabolic Markers ◽  
Stony Coral ◽  
Differential Outcomes ◽  
Betaine Lipids ◽  
Montastraea Cavernosa ◽  
Apparently Healthy

Stony coral tissue loss disease, first observed in Florida in 2014, has now spread along the entire Florida Reef Tract and on reefs in many Caribbean countries. The disease affects a variety of coral species with differential outcomes, and in many instances results in whole-colony mortality. We employed untargeted metabolomic profiling of Montastraea cavernosa corals affected by stony coral tissue loss disease to identify metabolic markers of disease. Herein, extracts from apparently healthy, diseased, and recovered Montastraea cavernosa collected at a reef site near Ft. Lauderdale, Florida were subjected to liquid-chromatography mass spectrometry-based metabolomics. Unsupervised principal component analysis reveals wide variation in metabolomic profiles of healthy corals of the same species, which differ from diseased corals. Using a combination of supervised and unsupervised data analyses tools, we describe metabolite features that explain variation between the apparently healthy corals, between diseased corals, and between the healthy and the diseased corals. By employing a culture-based approach, we assign sources of a subset of these molecules to the endosymbiotic dinoflagellates, Symbiodiniaceae. Specifically, we identify various endosymbiont- specific lipid classes, such as betaine lipids, glycolipids, and tocopherols, which differentiate samples taken from apparently healthy corals and diseased corals. Given the variation observed in metabolite fingerprints of corals, our data suggests that metabolomics is a viable approach to link metabolite profiles of different coral species with their susceptibility and resilience to numerous coral diseases spreading through reefs worldwide.

scholarly journals Microbial community shifts associated with the ongoing stony coral tissue loss disease outbreak on the Florida Reef Tract

2019 ◽  
Author(s):  
Julie L. Meyer ◽  
Jessy Castellanos-Gell ◽  
Greta S. Aeby ◽  
Claudia Häse ◽  
Blake Ushijima ◽  
...  
Keyword(s):  
Coral Species ◽  
Initial Step ◽  
Disease Outbreak ◽  
Healthy Tissue ◽  
Tissue Loss ◽  
Coral Tissue ◽  
Florida Reef Tract ◽  
Stony Coral ◽  
Reef Tract ◽  
Apparently Healthy

ABSTRACTAs many as 22 of the 45 coral species on the Florida Reef Tract are currently affected by stony coral tissue loss disease (SCTLD). The ongoing disease outbreak was first observed in 2014 in Southeast Florida near Miami and as of early 2019 has been documented from the northernmost reaches of the reef tract in Martin County down to Key West. We examined the microbiota associated with disease lesions and apparently healthy tissue on diseased colonies of Montastraea cavernosa, Orbicella faveolata, Diploria labyrinthiformis, and Dichocoenia stokesii. Analysis of differentially abundant taxa between disease lesions and apparently healthy tissue identified five unique amplicon sequence variants enriched in the diseased tissue in three of the coral species, namely an unclassified genus of Flavobacteriales and sequences identified as Fusibacter (Clostridiales), Planktotalea (Rhodobacterales), Algicola (Alteromonadales), and Vibrio (Vibrionales). In addition, several groups of likely opportunistic or saprophytic colonizers such as Epsilonbacteraeota, Patescibacteria, Clostridiales, Bacteroidetes, and Rhodobacterales were also enriched in SCTLD disease lesions. This work represents the first microbiological characterization of SCTLD, as an initial step toward identifying the potential pathogen(s) responsible for SCTLD.

scholarly journals Rapid Population Decline of the Pillar Coral Dendrogyra cylindrus Along the Florida Reef Tract

2020 ◽  
Author(s):  
Karen L. Neely ◽  
Cynthia L. Lewis
Keyword(s):  
Population Decline ◽  
Tissue Loss ◽  
Coral Tissue ◽  
Florida Reef Tract ◽  
Stony Coral ◽  
Chronic Stressors ◽  
The Status ◽  
Reef Tract ◽  
Functional Extinction ◽  
Dendrogyra Cylindrus

AbstractCoral reefs worldwide are in a state of decline, but the status of populations and stressors for rare species are generally not well documented using broad-scale monitoring protocol. We fate-tracked all known colonies of the pillar coral Dendrogyra cylindrus on the Florida Reef Tract from 2013 – 2020 to assess the population and document the impacts of chronic and acute stressors. Large average colony size, an absence of juveniles, and large geographic distances between genotypes suggest that the Florida D. cylindrus population has been reproductively extinct for decades. During the study period, low-intensity chronic stressors were balanced by regrowth, while back-to-back years of coral bleaching and thermally-exacerbated disease led to declines that the subsequent years of recovery suggest would take 11 uninterrupted years to overcome. The most recent stressor on Florida’s D. cylindrus population is “stony coral tissue loss disease.” Following the appearance of the disease in Florida in 2015, it resulted in unrecoverable losses to the D. cylindrus population as tissue, colonies, and whole genotypes were driven to extinction. Losses of 91% of coral tissue, 88% of colonies, and 73% of genotypes between 2014 and early 2020 have led to functional extinction of D. cylindrus on the Florida Reef Tract.

scholarly journals Exploring the Stony Coral Tissue Loss Disease Bacterial Pathobiome

2020 ◽  
Author(s):  
D.D. Iwanowicz ◽  
W.B. Schill ◽  
C. M. Woodley ◽  
A. Bruckner ◽  
K. Neely ◽  
...  
Keyword(s):  
Direct Sequencing ◽  
Bacterial Species ◽  
Tissue Loss ◽  
Coral Tissue ◽  
Coral Host ◽  
Dade County ◽  
Sequencing Data ◽  
Stony Coral ◽  
Clinically Normal ◽  
Diseased Coral

ABSTRACTA devastating novel coral disease outbreak, referred to as Stony Coral Tissue Loss Disease (SCTLD), was first described in 2014. It is thought to have originated offshore of Miami-Dade County, FL, but has persisted and spread, affecting new reefs along the Florida Reef Tract and reefs of at least 8 other Caribbean jurisdictions. We investigated the microbial communities of clinically normal and diseased specimens of five species of affected corals using targeted 16S ribosomal DNA sequencing (Illumina MiSeq). Fifty-nine bacterial sequences were identified using contrast analysis that had enriched abundance in diseased coral host microbiomes relative to the microbiomes of clinically normal hosts. Several sequences from known bacterial pathogens were identified in this group. Additionally, we identified fifty-three bacterial species that had differentially elevated numbers in clinically normal coral host samples relative to samples from diseased host corals. The bacterial consortia composing the clinically normal and diseased coral microbiomes were clearly distinct taxonomically. Predicted functional profiles based on taxonomy, however, were found to be quite similar. This indicates a high level of functional redundancy among diseased and clinically normal microbiome members. Further examination of the direct sequencing data revealed that while some bacteria were differentially distributed according to disease status, others were not. Fifty-one bacterial species were found in both diseased and clinically normal coral host samples and not differentially abundant in either disease state. These still may be important in explaining the presentation of disease.IMPORTANCEDetermining causation is a management top priority to guide control and intervention strategies for the SCTLD outbreak. Towards this goal we examined bacterial taxa that were differentially elevated in numbers in diseased corals as compared to clinically normal corals at Looe Key, FL in August 2018. Many of the bacterial species we detected are known to be pathogenic to humans, animals, and (or) plants, and some of these have been found associated with diseased corals in other studies. Microbes that were present (or conspicuous by their absence) in both diseased as well as clinically normal corals were also examined because “healthy” corals from a diseased location such as Looe Key may have been exposed but may not have been showing overt disease at the time of sampling. Although untangling of causation is not possible currently, certain bacterial cliques and excess nutrients appear to be potential risk factors in SCTLD pathology.

scholarly journals Metabolomics of healthy and stony coral tissue loss disease affected Montastraea cavernosa corals

2021 ◽  
Author(s):  
Jessica M Deutsch ◽  
Olakunle Jaiyesimi ◽  
Kelly Pitts ◽  
Jay Houk ◽  
Blake Ushijima ◽  
...  
Keyword(s):  
Coral Species ◽  
Principal Component ◽  
Tissue Loss ◽  
Coral Tissue ◽  
Metabolic Markers ◽  
Stony Coral ◽  
Differential Outcomes ◽  
Betaine Lipids ◽  
Montastraea Cavernosa ◽  
Apparently Healthy

Stony coral tissue loss disease, first observed in Florida in 2014, has now spread along the entire Florida Reef Tract and on reefs in many Caribbean countries. The disease affects a variety of coral species with differential outcomes, and in many instances results in whole-colony mortality. We employed untargeted metabolomic profiling of Montastraea cavernosa corals affected by stony coral tissue loss disease to identify metabolic markers of disease. Herein, extracts from apparently healthy, diseased, and recovered corals, Montastraea cavernosa, collected at a reef site near Ft. Lauderdale, Florida were subjected to liquid-chromatography mass spectrometry-based metabolomics. Unsupervised principal component analysis reveals wide variation in metabolomic profiles of healthy corals of the same species, which differ from diseased corals. Using a combination of supervised and unsupervised data analyses tools, we describe metabolite features that explain variation between the apparently healthy corals, between diseased corals, and between the healthy and the diseased corals. By employing a culture-based approach, we assign sources of a subset of these molecules to the endosymbiotic dinoflagellates, Symbiodiniaceae. Specifically, we identify various endosymbiont- specific lipid classes, such as betaine lipids, glycolipids, and tocopherols, which differentiate samples taken from apparently healthy corals and diseased corals. Given the variation observed in metabolite fingerprints of corals, our data suggests that metabolomics is a viable approach to link metabolite profiles of different coral species with their susceptibility and resilience to numerous coral diseases spreading through reefs worldwide.

scholarly journals Changing Stony Coral Tissue Loss Disease Dynamics Through Time in Montastraea cavernosa

2021 ◽  
Vol 8 ◽  
Author(s):  
Greta Aeby ◽  
Blake Ushijima ◽  
Erich Bartels ◽  
Cory Walter ◽  
Joseph Kuehl ◽  
...  
Keyword(s):  
Common Species ◽  
Disease Prevalence ◽  
Tissue Loss ◽  
Coral Tissue ◽  
Disease Dynamics ◽  
Western Atlantic ◽  
Fort Lauderdale ◽  
Stony Coral ◽  
Montastraea Cavernosa ◽  
Lesion Morphology

Stony coral tissue loss disease (SCTLD) is affecting corals across the Western Atlantic and displays species-specific and regional differences in prevalence, incidence, degree of mortality, and lesion morphology. We examined two Florida sites with different temporal histories of disease emergence; Fort Lauderdale where SCTLD is endemic and the Lower Florida Keys where SCTLD has recently emerged. Our objectives were to (1) assess the potential impact of SCTLD on overall reef condition by surveying reefs in each region, (2) in a single common species, Montastraea cavernosa, examine differences in SCTLD prevalence, colony mortality, and lesion morphology in each region, and (3) look for differences in contagion by conducting transmission experiments using lesions from each region. Reef surveys found sites in both regions had low coral cover, high algae cover, and similar coral species composition. SCTLD prevalence was higher in the Lower Keys than at Fort Lauderdale and two of the common species, M. cavernosa and S. siderea at Fort Lauderdale were dominated by smaller colonies (<5 cm) whereas larger colonies occurred in the Lower Keys. Tagged M. cavernosa SCTLD-affected colonies were followed for 2 years at one site in each region. In both years, Fort Lauderdale colonies showed declining disease prevalence, low colony mortality, and disease lesions were mainly bleached spots lacking tissue loss. In contrast, Lower Keys colonies tagged in the first year maintained 100% disease prevalence with high mortality, and disease lesions were predominantly tissue loss with no bleached edges. However, SCTLD dynamics changed, with year two tagged colonies showing declining disease prevalence, low mortality, and lesion morphology switched to a mixture of bleached polyps and tissue loss with or without bleached edges. Lesion morphology on colonies was a significant predictor of amount of tissue loss. Aquaria studies found the rate of SCTLD transmission using lesions from the different zones (emergent and endemic) were similar. Our study highlights that differences in coral mortality from SCTLD are not necessarily linked to host species, lesion morphology is reflective of subsequent rate of mortality, and disease dynamics change through time on reefs where the disease has newly emerged.

Reef-scale impacts of the stony coral tissue loss disease outbreak

Coral Reefs ◽  
2020 ◽  
Vol 39 (4) ◽  
pp. 861-866 ◽  
Author(s):  
Nuria Estrada-Saldívar ◽  
Ana Molina-Hernández ◽  
Esmeralda Pérez-Cervantes ◽  
Francisco Medellín-Maldonado ◽  
F. Javier González-Barrios ◽  
...  
Keyword(s):  
Disease Outbreak ◽  
Tissue Loss ◽  
Coral Tissue ◽  
Stony Coral

scholarly journals Stony Coral Tissue Loss Disease biomarker bacteria identified in corals and overlying waters using a rapid field-based sequencing approach

2021 ◽  
Author(s):  
Cynthia C. Becker ◽  
Marilyn Brandt ◽  
Carolyn A. Miller ◽  
Amy Apprill
Keyword(s):  
Coral Disease ◽  
The United States ◽  
Virgin Islands ◽  
Tissue Loss ◽  
Coral Tissue ◽  
Rna Sequences ◽  
Disease Biomarker ◽  
Stony Coral ◽  
Ribosomal Rna Sequences ◽  
Reef Tract

AbstractStony Coral Tissue Loss Disease (SCTLD) is a devastating disease. Since 2014, it has spread along the entire Florida Reef Tract, presumably via a water-borne vector, and into the greater Caribbean. It was first detected in the United States Virgin Islands (USVI) in January 2019. To more quickly identify disease biomarker microbes, we developed a rapid pipeline for microbiome sequencing. Over a span of 10 days we collected, processed, and sequenced coral tissue and near-coral seawater microbiomes from diseased and apparently healthy Colpophyllia natans, Montastraea cavernosa, Meandrina meandrites and Orbicella franksi. Analysis of the resulting bacterial and archaeal 16S ribosomal RNA sequences revealed 25 biomarker amplicon sequence variants (ASVs) enriched in diseased tissue. These biomarker ASVs were additionally recovered in near-coral seawater (within 5 cm of coral surface), a potential recruitment zone for pathogens. Phylogenetic analysis of the biomarker ASVs belonging to Vibrio, Arcobacter, Rhizobiaceae, and Rhodobacteraceae revealed relatedness to other coral disease-associated bacteria and lineages novel to corals. Additionally, four ASVs (Algicola, Cohaesibacter, Thalassobius and Vibrio) were exact sequence matches to microbes previously associated with SCTLD. This work represents the first rapid coral disease sequencing effort and identifies biomarkers of SCTLD that could be targets for future SCTLD research.

scholarly journals Considering Commercial Vessels as Potential Vectors of Stony Coral Tissue Loss Disease

2021 ◽  
Vol 8 ◽  
Author(s):  
Nicholas A. Rosenau ◽  
Sarah Gignoux-Wolfsohn ◽  
Richard A. Everett ◽  
A. Whitman Miller ◽  
Mark S. Minton ◽  
...  
Keyword(s):  
Ballast Water ◽  
Management Strategies ◽  
Tissue Loss ◽  
Coral Tissue ◽  
Caribbean Region ◽  
Future Research ◽  
Ship Traffic ◽  
Marine Invasion ◽  
Stony Coral ◽  
Resource Managers

Stony coral tissue loss disease (SCTLD) is a troubling new disease that is spreading rapidly across the greater Caribbean region, but the etiological agent(s) and the mechanisms(s) of spread are both unknown. First detected off the coast of Miami, Florida, major ocean currents alone do not explain the pattern of spread, with outbreaks occurring across geographically disjunct and distant locations. This has raised concerns by researchers and resource managers that commercial vessels may contribute as vectors to spread of the disease. Despite existing regulatory and management strategies intended to limit coastal marine invasion risks, the efficacy of these measures is still unresolved for ship-borne microorganisms, and disease transport via ballast water and hull biofouling are under examination given the high ship traffic in the region. Here, to help inform the discussion of ships as possible vectors of SCTLD, we provide an overview of the current state of knowledge about ships and their potential to transfer organisms in the greater Caribbean, focusing in particular on ballast water, and outline a set of recommendations for future research.

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