1
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Graham OJ, Adamczyk EM, Schenk S, Dawkins P, Burke S, Chei E, Cisz K, Dayal S, Elstner J, Hausner ALP, Hughes T, Manglani O, McDonald M, Mikles C, Poslednik A, Vinton A, Wegener Parfrey L, Harvell CD. Manipulation of the seagrass-associated microbiome reduces disease severity. Environ Microbiol 2024; 26:e16582. [PMID: 38195072 DOI: 10.1111/1462-2920.16582] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Accepted: 12/27/2023] [Indexed: 01/11/2024]
Abstract
Host-associated microbes influence host health and function and can be a first line of defence against infections. While research increasingly shows that terrestrial plant microbiomes contribute to bacterial, fungal, and oomycete disease resistance, no comparable experimental work has investigated marine plant microbiomes or more diverse disease agents. We test the hypothesis that the eelgrass (Zostera marina) leaf microbiome increases resistance to seagrass wasting disease. From field eelgrass with paired diseased and asymptomatic tissue, 16S rRNA gene amplicon sequencing revealed that bacterial composition and richness varied markedly between diseased and asymptomatic tissue in one of the two years. This suggests that the influence of disease on eelgrass microbial communities may vary with environmental conditions. We next experimentally reduced the eelgrass microbiome with antibiotics and bleach, then inoculated plants with Labyrinthula zosterae, the causative agent of wasting disease. We detected significantly higher disease severity in eelgrass with a native microbiome than an experimentally reduced microbiome. Our results over multiple experiments do not support a protective role of the eelgrass microbiome against L. zosterae. Further studies of these marine host-microbe-pathogen relationships may continue to show new relationships between plant microbiomes and diseases.
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Affiliation(s)
- Olivia J Graham
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, New York, USA
| | - Emily M Adamczyk
- Department of Zoology and Biodiversity Research Centre, Unceded xʷməθkʷəy̓əm (Musqueam) Territory, University of British Columbia, Vancouver, British Columbia, Canada
| | - Siobhan Schenk
- Department of Botany, University of British Columbia, Vancouver, British Columbia, Canada
| | - Phoebe Dawkins
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, New York, USA
| | - Samantha Burke
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, New York, USA
| | - Emily Chei
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, New York, USA
| | - Kaitlyn Cisz
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, New York, USA
| | - Sukanya Dayal
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, New York, USA
| | - Jack Elstner
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, New York, USA
| | | | - Taylor Hughes
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, New York, USA
| | - Omisha Manglani
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, New York, USA
| | - Miles McDonald
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, New York, USA
| | - Chloe Mikles
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, New York, USA
| | - Anna Poslednik
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, New York, USA
| | - Audrey Vinton
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, New York, USA
| | - Laura Wegener Parfrey
- Department of Zoology and Biodiversity Research Centre, Unceded xʷməθkʷəy̓əm (Musqueam) Territory, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Botany, University of British Columbia, Vancouver, British Columbia, Canada
| | - C Drew Harvell
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, New York, USA
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2
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Geraci-Yee S, Collier JL, Allam B. A Microcosm Experiment Reveals the Temperature-Sensitive Release of Mucochytrium quahogii (=QPX) from Hard Clams and Pallial Fluid as a Stable QPX Reservoir. Microorganisms 2024; 12:241. [PMID: 38399645 PMCID: PMC10892119 DOI: 10.3390/microorganisms12020241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Revised: 01/03/2024] [Accepted: 01/20/2024] [Indexed: 02/25/2024] Open
Abstract
Mucochytrium quahogii, also known as QPX or Quahog Parasite Unknown, is the causative agent of QPX disease in the hard clam (Mercenaria mercenaria). Host-pathogen-environment interactions between M. quahogii, the hard clam, and temperature were explored in a microcosm experiment. Hard clams were housed in individual tanks with sterile seawater under two temperature regimes: low (13 °C) temperature, which is thought to be optimal for QPX disease development, and high (20 °C) temperature, which has been shown to promote "healing" of QPX-infected clams. Hard clam tissue, pallial fluid, seawater, and shell biofilms were collected and assayed for M. quahogii. The release of M. quahogii from naturally infected live hard clams into seawater was detected only in the low temperature treatment, suggesting that temperature influences the release of potentially infectious cells. M. quahogii was commonly found in hard clam pallial fluid, even after 9 weeks in the lab, suggesting pallial fluid is a stable reservoir of M. quahogii within its primary host and that M. quahogii is not a transient component of the hard clam microbiota. Overall, results support a host-specific relationship and that M. quahogii is a commensal member of the hard clam microbiota, supporting its classification as an opportunistic pathogen.
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Affiliation(s)
| | | | - Bassem Allam
- School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, New York, NY 11794, USA (J.L.C.)
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3
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Graham OJ, Stephens T, Rappazzo B, Klohmann C, Dayal S, Adamczyk EM, Olson A, Hessing-Lewis M, Eisenlord M, Yang B, Burge C, Gomes CP, Harvell D. Deeper habitats and cooler temperatures moderate a climate-driven seagrass disease. Philos Trans R Soc Lond B Biol Sci 2023; 378:20220016. [PMID: 36744566 PMCID: PMC9900705 DOI: 10.1098/rstb.2022.0016] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Eelgrass creates critical coastal habitats worldwide and fulfills essential ecosystem functions as a foundation seagrass. Climate warming and disease threaten eelgrass, causing mass mortalities and cascading ecological impacts. Subtidal meadows are deeper than intertidal and may also provide refuge from the temperature-sensitive seagrass wasting disease. From cross-boundary surveys of 5761 eelgrass leaves from Alaska to Washington and assisted with a machine-language algorithm, we measured outbreak conditions. Across summers 2017 and 2018, disease prevalence was 16% lower for subtidal than intertidal leaves; in both tidal zones, disease risk was lower for plants in cooler conditions. Even in subtidal meadows, which are more environmentally stable and sheltered from temperature and other stressors common for intertidal eelgrass, we observed high disease levels, with half of the sites exceeding 50% prevalence. Models predicted reduced disease prevalence and severity under cooler conditions, confirming a strong interaction between disease and temperature. At both tidal zones, prevalence was lower in more dense eelgrass meadows, suggesting disease is suppressed in healthy, higher density meadows. These results underscore the value of subtidal eelgrass and meadows in cooler locations as refugia, indicate that cooling can suppress disease, and have implications for eelgrass conservation and management under future climate change scenarios. This article is part of the theme issue 'Infectious disease ecology and evolution in a changing world'.
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Affiliation(s)
- Olivia J. Graham
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY 14853-0001, USA
| | | | - Brendan Rappazzo
- Department of Computer Science, Cornell University, Ithaca, NY 14850, USA
| | - Corinne Klohmann
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY 14853-0001, USA
| | - Sukanya Dayal
- Department of Natural Resources, Cornell University, Ithaca, NY 14853, USA,Department of Biology and Marine Biology, University of North Carolina, Wilmington, NC 28403-5915, USA
| | - Emily M. Adamczyk
- Department of Zoology and Biodiversity Research Centre, University of British Columbia, Unceded xməθkəy̓əm (Musqueam) Territory, Vancouver, British Columbia, Canada V6T 1Z4
| | - Angeleen Olson
- Hakai Institute, Calvert Island, P.O. Box 25039, Campbell River, British Columbia, Canada V9W 0B7
| | - Margot Hessing-Lewis
- Hakai Institute, Calvert Island, P.O. Box 25039, Campbell River, British Columbia, Canada V9W 0B7
| | - Morgan Eisenlord
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY 14853-0001, USA
| | - Bo Yang
- Department of Urban and Regional Planning, San Jose State University, San Jose, CA 95112, USA
| | - Colleen Burge
- Institute of Marine and Environmental Technology, University of Maryland Baltimore County, Baltimore, MD 21202, USA,Department of Microbiology and Immunology, University of Maryland Baltimore, Baltimore, MD 21201, USA
| | - Carla P. Gomes
- Department of Computer Science, Cornell University, Ithaca, NY 14850, USA
| | - Drew Harvell
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY 14853-0001, USA
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4
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Schenck FR, DuBois K, Kardish MR, Stachowicz JJ, Hughes AR. The effect of warming on seagrass wasting disease depends on host genotypic identity and diversity. Ecology 2023; 104:e3959. [PMID: 36530038 DOI: 10.1002/ecy.3959] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Accepted: 08/22/2022] [Indexed: 12/23/2022]
Abstract
Temperature increases due to climate change have affected the distribution and severity of diseases in natural systems, causing outbreaks that can destroy host populations. Host identity, diversity, and the associated microbiome can affect host responses to both infection and temperature, but little is known about how they could function as important mediators of disease in altered thermal environments. We conducted an 8-week warming experiment to test the independent and interactive effects of warming, host genotypic identity, and host genotypic diversity on the prevalence and intensity of infections of seagrass (Zostera marina) by the wasting disease parasite (Labyrinthula zosterae). At elevated temperatures, we found that genotypically diverse host assemblages had reduced infection intensity, but not reduced prevalence, relative to less diverse assemblages. This dilution effect on parasite intensity was the result of both host composition effects as well as emergent properties of biodiversity. In contrast with the benefits of genotypic diversity under warming, diversity actually increased parasite intensity slightly in ambient temperatures. We found mixed support for the hypothesis that a growth-defense trade-off contributed to elevated disease intensity under warming. Changes in the abundance (but not composition) of a few taxa in the host microbiome were correlated with genotype-specific responses to wasting disease infections under warming, consistent with the emerging evidence linking changes in the host microbiome to the outcome of host-parasite interactions. This work emphasizes the context dependence of biodiversity-disease relationships and highlights the potential importance of interactions among biodiversity loss, climate change, and disease outbreaks in a key foundation species.
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Affiliation(s)
- Forest R Schenck
- Marine Science Center, Northeastern University, Nahant, Massachusetts, USA.,Massachusetts Division of Marine Fisheries, Gloucester, Massachusetts, USA
| | - Katherine DuBois
- Department of Evolution and Ecology, University of California, Davis, California, USA
| | - Melissa R Kardish
- Department of Evolution and Ecology, University of California, Davis, California, USA
| | - John J Stachowicz
- Department of Evolution and Ecology, University of California, Davis, California, USA.,Center for Population Biology, University of California, Davis, California, USA
| | - A Randall Hughes
- Marine Science Center, Northeastern University, Nahant, Massachusetts, USA
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5
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Predictable Changes in Eelgrass Microbiomes with Increasing Wasting Disease Prevalence across 23° Latitude in the Northeastern Pacific. mSystems 2022; 7:e0022422. [PMID: 35856664 PMCID: PMC9426469 DOI: 10.1128/msystems.00224-22] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
Predicting outcomes of marine disease outbreaks presents a challenge in the face of both global and local stressors. Host-associated microbiomes may play important roles in disease dynamics but remain understudied in marine ecosystems. Host–pathogen–microbiome interactions can vary across host ranges, gradients of disease, and temperature; studying these relationships may aid our ability to forecast disease dynamics. Eelgrass, Zostera marina, is impacted by outbreaks of wasting disease caused by the opportunistic pathogen Labyrinthula zosterae. We investigated how Z. marina phyllosphere microbial communities vary with rising wasting disease lesion prevalence and severity relative to plant and meadow characteristics like shoot density, longest leaf length, and temperature across 23° latitude in the Northeastern Pacific. We detected effects of geography (11%) and smaller, but distinct, effects of temperature (30-day max sea surface temperature, 4%) and disease (lesion prevalence, 3%) on microbiome composition. Declines in alpha diversity on asymptomatic tissue occurred with rising wasting disease prevalence within meadows. However, no change in microbiome variability (dispersion) was detected between asymptomatic and symptomatic tissues. Further, we identified members of Cellvibrionaceae, Colwelliaceae, and Granulosicoccaceae on asymptomatic tissue that are predictive of wasting disease prevalence across the geographic range (3,100 kilometers). Functional roles of Colwelliaceae and Granulosicoccaceae are not known. Cellvibrionaceae, degraders of plant cellulose, were also enriched in lesions and adjacent green tissue relative to nonlesioned leaves. Cellvibrionaceae may play important roles in disease progression by degrading host tissues or overwhelming plant immune responses. Thus, inclusion of microbiomes in wasting disease studies may improve our ability to understand variable rates of infection, disease progression, and plant survival. IMPORTANCE The roles of marine microbiomes in disease remain poorly understood due, in part, to the challenging nature of sampling at appropriate spatiotemporal scales and across natural gradients of disease throughout host ranges. This is especially true for marine vascular plants like eelgrass (Zostera marina) that are vital for ecosystem function and biodiversity but are susceptible to rapid decline and die-off from pathogens like eukaryotic slime-mold Labyrinthula zosterae (wasting disease). We link bacterial members of phyllosphere tissues to the prevalence of wasting disease across the broadest geographic range to date for a marine plant microbiome-disease study (3,100 km). We identify Cellvibrionaceae, plant cell wall degraders, enriched (up to 61% relative abundance) within lesion tissue, which suggests this group may be playing important roles in disease progression. These findings suggest inclusion of microbiomes in marine disease studies will improve our ability to predict ecological outcomes of infection across variable landscapes spanning thousands of kilometers.
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6
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Ferrari J, Goncalves P, Campbell AH, Sudatti DB, Wood GV, Thomas T, Pereira RC, Steinberg PD, Marzinelli EM. Molecular analysis of a fungal disease in the habitat-forming brown macroalga Phyllospora comosa (Fucales) along a latitudinal gradient. JOURNAL OF PHYCOLOGY 2021; 57:1504-1516. [PMID: 33942303 DOI: 10.1111/jpy.13180] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2020] [Accepted: 04/09/2021] [Indexed: 06/12/2023]
Abstract
Infectious diseases affecting habitat-forming species can have significant impacts on population dynamics and alter the structure and functioning of marine ecosystems. Recently, a fungal infection was described as the causative agent of necrotic lesions on the stipe of the forest-forming macroalga Phyllospora comosa, a disease named "stipe rot" (SR). Here, we developed a quantitative PCR (qPCR) method for rapid detection and quantification of this pathogen, which was applied to evaluate the level of SR infection in eight P. comosa populations spanning the entire latitudinal distribution of this species along southeastern Australia. We also investigated the relationship between the abundance and prevalence of Stipe Rot Fungus (SRF) and potential host chemical defenses as well as its relationship with morphological and ecophysiological traits of P. comosa. qPCR estimates of SRF abundance reflected the levels of infection estimated by visual assessment, with higher numbers of SRF copies being observed in individuals showing high or intermediate levels of visual symptoms of SR. Concordance of conventional PCR and visual assessments was 92 and 94%, respectively, compared to qPCR detection. SRF prevalence was positively related to fucoxanthin content and herbivory, but not significant related to other traits measured (phlorotannin content, total length, thallus diameter, stipe width, number of branches, frond width, fouling, bleaching, gender, and photosynthetic efficiency). These results provide confidence for previous reports of this disease based upon visual assessments only, contribute to the development of monitoring and conservation strategies for safeguarding P. comosa forests, and generate insights into potential factors influencing host-pathogen interactions in this system.
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Affiliation(s)
- Juliana Ferrari
- Instituto de Biologia, Departamento de Biologia Marinha, Universidade Federal Fluminense, Outeiro de São Jõao Batista s/n, Niterói, RJ, 24.001-970, Brazil
- Instituto de Estudos do Mar Almirante Paulo Moreira, Arraial do Cabo, RJ, 28930-000, Brazil
- Centre for Marine Science and Innovation, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, NSW, 2052, Australia
- Sydney Institute of Marine Science, Mosman, NSW, 2088, Australia
| | - Priscila Goncalves
- Centre for Marine Science and Innovation, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, NSW, 2052, Australia
| | - Alexandra Helene Campbell
- Centre for Marine Science and Innovation, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, NSW, 2052, Australia
- Seaweed Research Group, University of the Sunshine Coast, 90 Sippy Downs Road, Sunshine Coast, Queensland, 4556, Australia
| | - Daniela Bueno Sudatti
- Instituto de Estudos do Mar Almirante Paulo Moreira, Arraial do Cabo, RJ, 28930-000, Brazil
- Universidade Federal Fluminense, Niterói, RJ, 24.001-970, Brazil
| | - Georgina Valentine Wood
- Centre for Marine Science and Innovation, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, NSW, 2052, Australia
- School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW, 2006, Australia
| | - Torsten Thomas
- Centre for Marine Science and Innovation, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, NSW, 2052, Australia
| | - Renato Crespo Pereira
- Instituto de Pesquisas Jardim Botânico do Rio de Janeiro, Rio de Janeiro, RJ, 22460-030, Brazil
- Universidade Federal Fluminense, Niterói, RJ, 24.001-970, Brazil
| | - Peter David Steinberg
- Centre for Marine Science and Innovation, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, NSW, 2052, Australia
- Sydney Institute of Marine Science, Mosman, NSW, 2088, Australia
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technical University, Singapore, 637551, Singapore
| | - Ezequiel Miguel Marzinelli
- Sydney Institute of Marine Science, Mosman, NSW, 2088, Australia
- School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW, 2006, Australia
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technical University, Singapore, 637551, Singapore
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7
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Duffin P, Martin DL, Pagenkopp Lohan KM, Ross C. Integrating host immune status, Labyrinthula spp. load and environmental stress in a seagrass pathosystem: Assessing immune markers and scope of a new qPCR primer set. PLoS One 2020; 15:e0230108. [PMID: 32168322 PMCID: PMC7069685 DOI: 10.1371/journal.pone.0230108] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Accepted: 02/23/2020] [Indexed: 11/20/2022] Open
Abstract
Recent trends suggest that marine disease outbreaks caused by opportunistic pathogens are increasing in frequency and severity. One such malady is seagrass wasting disease, caused by pathogens in the genus Labyrinthula. It is suspected that pathogenicity is intimately linked to the ability of the host to initiate defense responses; however, supportive evidence is lacking. To address this, we developed two techniques, including 1) a new qPCR-based pathogen detection method, and 2) an immune profiling panel via four host-biomarker assays (measuring peroxidase, exochitinase, polyphenol oxidase, and lysozyme activities). These techniques were then used to experimentally investigate the impact of environmental stressors (namely, elevated temperature and salinity) on host immunity and how immune status might affect susceptibility to Labyrinthula infection. In the first experiment, we subjected individual turtlegrass (Thalassia testudinum) shoots to short-term (7 d) abiotic stressors alone. In a second experiment, the same abiotic stressor conditions were followed by pathogen exposure (7 additional d), simulating a scenario where we attempt to isolate the impact of environmental stressors on the host seagrass species by removing the stressor as the pathogen is introduced. The qPCR assay successfully quantified the abundance of Labyrinthula spp. cells from both pure cultures and seagrass tissues across a broad range of predominately pathogenic strains, with high sensitivity. Immune enzyme assays revealed that all four biomarkers were constitutively active in turtlegrass individuals, but specific activities were largely unaffected by the chosen abiotic stressor conditions. We also identified positive correlations between pathogen load and two biomarkers (peroxidase, exochitinase), regardless of abiotic stress treatment, further demonstrating the potential utility of these biomarkers in future applications.
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Affiliation(s)
- Paige Duffin
- Department of Biology, University of North Florida, Jacksonville, Florida, United States of America
| | - Daniel L. Martin
- Department of Biology, University of North Florida, Jacksonville, Florida, United States of America
| | | | - Cliff Ross
- Department of Biology, University of North Florida, Jacksonville, Florida, United States of America
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8
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Saha M, Barboza FR, Somerfield PJ, Al-Janabi B, Beck M, Brakel J, Ito M, Pansch C, Nascimento-Schulze JC, Jakobsson Thor S, Weinberger F, Sawall Y. Response of foundation macrophytes to near-natural simulated marine heatwaves. GLOBAL CHANGE BIOLOGY 2020; 26:417-430. [PMID: 31670451 DOI: 10.1111/gcb.14801] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Revised: 07/27/2019] [Accepted: 07/29/2019] [Indexed: 05/24/2023]
Abstract
Marine heatwaves have been observed worldwide and are expected to increase in both frequency and intensity due to climate change. Such events may cause ecosystem reconfigurations arising from species range contraction or redistribution, with ecological, economic and social implications. Macrophytes such as the brown seaweed Fucus vesiculosus and the seagrass Zostera marina are foundation species in many coastal ecosystems of the temperate northern hemisphere. Hence, their response to extreme events can potentially determine the fate of associated ecosystems. Macrophyte functioning is intimately linked to the maintenance of photosynthesis, growth and reproduction, and resistance against pathogens, epibionts and grazers. We investigated morphological, physiological, pathological and chemical defence responses of western Baltic Sea F. vesiculosus and Z. marina populations to simulated near-natural marine heatwaves. Along with (a) the control, which constituted no heatwave but natural stochastic temperature variability (0HW), two treatments were applied: (b) two late-spring heatwaves (June, July) followed by a summer heatwave (August; 3HW) and (c) a summer heatwave only (1HW). The 3HW treatment was applied to test whether preconditioning events can modulate the potential sensitivity to the summer heatwave. Despite the variety of responses measured in both species, only Z. marina growth was impaired by the accumulative heat stress imposed by the 3HW treatment. Photosynthetic rate, however, remained high after the last heatwave indicating potential for recovery. Only epibacterial abundance was significantly affected in F. vesiculosus. Hence both macrophytes, and in particular F. vesiculosus, seem to be fairly tolerant to short-term marine heatwaves at least at the intensities applied in this experiment (up to 5°C above mean temperature over a period of 9 days). This may partly be due to the fact that F. vesiculosus grows in a highly variable environment, and may have a high phenotypic plasticity.
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Affiliation(s)
- Mahasweta Saha
- GEOMAR Helmholtz Centre for Ocean Research, Kiel, Germany
- School of Biological Sciences, University of Essex, Colchester, UK
- Plymouth Marine Laboratory, Plymouth, UK
| | | | | | | | - Miriam Beck
- GEOMAR Helmholtz Centre for Ocean Research, Kiel, Germany
| | - Janina Brakel
- GEOMAR Helmholtz Centre for Ocean Research, Kiel, Germany
- The Scottish Association for Marine Science, Oban, UK
| | - Maysa Ito
- GEOMAR Helmholtz Centre for Ocean Research, Kiel, Germany
| | | | - Jennifer C Nascimento-Schulze
- GEOMAR Helmholtz Centre for Ocean Research, Kiel, Germany
- Bioscience, College of Life and Environmental Science, University of Exeter, Exeter, UK
| | | | | | - Yvonne Sawall
- GEOMAR Helmholtz Centre for Ocean Research, Kiel, Germany
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9
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Sullivan BK, Trevathan-Tackett SM, Neuhauser S, Govers LL. Review: Host-pathogen dynamics of seagrass diseases under future global change. MARINE POLLUTION BULLETIN 2018; 134:75-88. [PMID: 28965923 PMCID: PMC6445351 DOI: 10.1016/j.marpolbul.2017.09.030] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2017] [Revised: 09/11/2017] [Accepted: 09/13/2017] [Indexed: 06/07/2023]
Abstract
Human-induced global change is expected to amplify the disease risk for marine biota. However, the role of disease in the rapid global decline of seagrass is largely unknown. Global change may enhance seagrass susceptibility to disease through enhanced physiological stress, while simultaneously promoting pathogen development. This review outlines the characteristics of disease-forming organisms and potential impacts of global change on three groups of known seagrass pathogens: labyrinthulids, oomycetes and Phytomyxea. We propose that hypersalinity, climate warming and eutrophication pose the greatest risk for increasing frequency of disease outbreaks in seagrasses by increasing seagrass stress and lowering seagrass resilience. In some instances, global change may also promote pathogen development. However, there is currently a paucity of information on these seagrass pathosystems. We emphasise the need to expand current research to better understand the seagrass-pathogen relationships, serving to inform predicative modelling and management of seagrass disease under future global change scenarios.
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Affiliation(s)
- Brooke K Sullivan
- School of Biosciences, The University of Melbourne, Parkville Campus, Parkville, Victoria 3010, Australia; Victorian Marine Science Consortium, 2A Bellarine Highway, Queenscliff, Victoria 3225, Australia.
| | - Stacey M Trevathan-Tackett
- Centre for Integrative Ecology, School of Life and Environmental Sciences, Deakin University, Burwood, Victoria, Australia.
| | - Sigrid Neuhauser
- Institute of Microbiology, University of Innsbruck, Technikerstr. 2, 6020 Innsbruck, Austria.
| | - Laura L Govers
- Conservation Ecology Group, Groningen Institute for Evolutionary Life Sciences, University of Groningen, Post Office Box 11103, 9700 CC Groningen, The Netherlands; Department of Aquatic Ecology and Environmental Biology, Institute for Water and Wetland Research, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands.
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10
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Schwelm A, Badstöber J, Bulman S, Desoignies N, Etemadi M, Falloon RE, Gachon CMM, Legreve A, Lukeš J, Merz U, Nenarokova A, Strittmatter M, Sullivan BK, Neuhauser S. Not in your usual Top 10: protists that infect plants and algae. MOLECULAR PLANT PATHOLOGY 2018; 19:1029-1044. [PMID: 29024322 PMCID: PMC5772912 DOI: 10.1111/mpp.12580] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2017] [Revised: 07/06/2017] [Accepted: 07/07/2017] [Indexed: 05/09/2023]
Abstract
Fungi, nematodes and oomycetes belong to the most prominent eukaryotic plant pathogenic organisms. Unicellular organisms from other eukaryotic lineages, commonly addressed as protists, also infect plants. This review provides an introduction to plant pathogenic protists, including algae infecting oomycetes, and their current state of research.
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Affiliation(s)
- Arne Schwelm
- Department of Plant Biology, Uppsala BioCentre, Linnean Centre for Plant BiologySwedish University of Agricultural SciencesUppsala SE‐75007Sweden
- Institute of Microbiology, University of InnsbruckInnsbruck 6020Austria
| | - Julia Badstöber
- Institute of Microbiology, University of InnsbruckInnsbruck 6020Austria
| | - Simon Bulman
- New Zealand Institute for Plant and Food Research LtdLincoln 7608New Zealand
| | - Nicolas Desoignies
- Applied Plant Ecophysiology, Haute Ecole Provinciale de Hainaut‐CondorcetAth 7800Belgium
| | - Mohammad Etemadi
- Institute of Microbiology, University of InnsbruckInnsbruck 6020Austria
| | - Richard E. Falloon
- New Zealand Institute for Plant and Food Research LtdLincoln 7608New Zealand
| | - Claire M. M. Gachon
- The Scottish Association for Marine ScienceScottish Marine InstituteOban PA37 1QAUK
| | - Anne Legreve
- Université catholique de Louvain, Earth and Life InstituteLouvain‐la‐Neuve 1348Belgium
| | - Julius Lukeš
- Institute of Parasitology, Biology Centre37005 České Budějovice (Budweis)Czech Republic
- Faculty of SciencesUniversity of South Bohemia37005 České Budějovice (Budweis)Czech Republic
- Integrated Microbial Biodiversity, Canadian Institute for Advanced ResearchTorontoOntario M5G 1Z8Canada
| | - Ueli Merz
- Plant PathologyInstitute of Integrative Biology, ETH Zurich, Zurich 8092Switzerland
| | - Anna Nenarokova
- Institute of Parasitology, Biology Centre37005 České Budějovice (Budweis)Czech Republic
- Faculty of SciencesUniversity of South Bohemia37005 České Budějovice (Budweis)Czech Republic
| | - Martina Strittmatter
- The Scottish Association for Marine ScienceScottish Marine InstituteOban PA37 1QAUK
- Present address:
Station Biologique de Roscoff, CNRS – UPMC, UMR7144 Adaptation and Diversity in the Marine Environment, Place Georges Teissier, CS 90074, 29688 Roscoff CedexFrance
| | - Brooke K. Sullivan
- School of BiosciencesUniversity of Melbourne, Parkville, Vic. 3010Australia
- School of BiosciencesVictorian Marine Science ConsortiumQueenscliffVic. 3225Australia
| | - Sigrid Neuhauser
- Institute of Microbiology, University of InnsbruckInnsbruck 6020Austria
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11
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Pathogenic Labyrinthula associated with Australian seagrasses: Considerations for seagrass wasting disease in the southern hemisphere. Microbiol Res 2017; 206:74-81. [PMID: 29146262 DOI: 10.1016/j.micres.2017.10.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Accepted: 10/07/2017] [Indexed: 10/18/2022]
Abstract
Marine disease ecology is a growing field of research, particularly for host organisms negatively impacted by a changing climate and anthropogenic activities. A decrease in health and increase in susceptibility to disease has been hypothesised as the mechanism behind wide-spread seagrass die-offs related to wasting disease in the past. However, seagrass wasting disease and the causative pathogen, Labyrinthula, have been vastly understudied in the southern hemisphere. Our aim was to build on the current knowledge of Australian Labyrinthula descriptions and phylogeny, while also providing a first look at wasting disease ecology in Australia. Five seagrass species along a 750km stretch of coastline in southeastern Australia were sampled. The resulting 38 Labyrinthula isolates represented a diversity of morphotypes and five haplotypes of varying phylogenetic clade positions and virulence. The haplotypes clustered with previously-described phylogenetic clades containing isolates from Asia, USA and Europe. Pathogenicity tests confirmed, for the first time, the presence of at least two pathogenic haplotypes in Australia. While historically there have been no reports of wasting disease-related seagrass habitat loss, the presence of pathogenic Labyrinthula highlights the need for disease monitoring and research to understand seagrass wasting disease ecology in Australia.
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12
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Irvine MA, Bull JC, Keeling MJ. Disease transmission promotes evolution of host spatial patterns. J R Soc Interface 2017; 13:rsif.2016.0463. [PMID: 27628172 PMCID: PMC5046947 DOI: 10.1098/rsif.2016.0463] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Accepted: 08/23/2016] [Indexed: 11/12/2022] Open
Abstract
Ecological dynamics can produce a variety of striking patterns. On ecological time scales, pattern formation has been hypothesized to be due to the interaction between a species and its local environment. On longer time scales, evolutionary factors must be taken into account. To examine the evolutionary robustness of spatial pattern formation, we construct a spatially explicit model of vegetation in the presence of a pathogen. Initially, we compare the dynamics for vegetation parameters that lead to competition induced spatial patterns and those that do not. Over ecological time scales, banded spatial patterns dramatically reduced the ability of the pathogen to spread, lowered its endemic density and hence increased the persistence of the vegetation. To gain an evolutionary understanding, each plant was given a heritable trait defining its resilience to competition; greater competition leads to lower vegetation density but stronger spatial patterns. When a disease is introduced, the selective pressure on the plant's resilience to the competition parameter is determined by the transmission of the disease. For high transmission, vegetation that has low resilience to competition and hence strong spatial patterning is an evolutionarily stable strategy. This demonstrates a novel mechanism by which striking spatial patterns can be maintained by disease-driven selection.
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Affiliation(s)
- Michael A Irvine
- Centre for Complexity Science, University of Warwick, Coventry, UK
| | - James C Bull
- Department of Biosciences, University of Swansea, Swansea, UK
| | - Matthew J Keeling
- Mathematics Institute and Department of Biological Sciences, University of Warwick, Coventry, UK
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13
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Jueterbock A, Franssen SU, Bergmann N, Gu J, Coyer JA, Reusch TBH, Bornberg-Bauer E, Olsen JL. Phylogeographic differentiation versus transcriptomic adaptation to warm temperatures inZostera marina, a globally important seagrass. Mol Ecol 2016; 25:5396-5411. [DOI: 10.1111/mec.13829] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Revised: 08/15/2016] [Accepted: 08/23/2016] [Indexed: 12/17/2022]
Affiliation(s)
- A. Jueterbock
- Faculty of Biosciences and Aquaculture; Nord University; Universitetsalleen 11 Bodø 8049 Norway
| | - S. U. Franssen
- Institut für Populationsgenetik; Vetmeduni Vienna; Veterinärplatz 1 Vienna 1210 Austria
- Institute for Evolution and Biodiversity; University of Münster; Hüfferstr. 1 Münster 48149 Germany
| | - N. Bergmann
- Integrated School of Ocean Sciences (ISOS); Kiel University; Leibnizstr. 3 Kiel 24098 Germany
| | - J. Gu
- Institute for Evolution and Biodiversity; University of Münster; Hüfferstr. 1 Münster 48149 Germany
| | - J. A. Coyer
- Shoals Marine Laboratory; University of New Hampshire; Durham NH 03824 USA
- Groningen Institute for Evolutionary Life Sciences; Ecological and Evolutionary Genomics Group; University of Groningen; P.O. Box 11103 Groningen 9700 CC The Netherlands
| | - T. B. H. Reusch
- GEOMAR Helmholtz-Centre for Ocean Research Kiel; Evolutionary Ecology of Marine Fishes; Düsternbrooker Weg 20 Kiel 24105 Germany
| | - E. Bornberg-Bauer
- Institute for Evolution and Biodiversity; University of Münster; Hüfferstr. 1 Münster 48149 Germany
| | - J. L. Olsen
- Groningen Institute for Evolutionary Life Sciences; Ecological and Evolutionary Genomics Group; University of Groningen; P.O. Box 11103 Groningen 9700 CC The Netherlands
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14
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Groner ML, Burge CA, Kim CJS, Rees E, Van Alstyne KL, Yang S, Wyllie-Echeverria S, Harvell CD. Plant characteristics associated with widespread variation in eelgrass wasting disease. DISEASES OF AQUATIC ORGANISMS 2016; 118:159-168. [PMID: 26912046 DOI: 10.3354/dao02962] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Seagrasses are ecosystem engineers of essential marine habitat. Their populations are rapidly declining worldwide. One potential cause of seagrass population declines is wasting disease, which is caused by opportunistic pathogens in the genus Labyrinthula. While infection with these pathogens is common in seagrasses, theory suggests that disease only occurs when environmental stressors cause immunosuppression of the host. Recent evidence suggests that host factors may also contribute to disease caused by opportunistic pathogens. In order to quantify patterns of disease, identify risk factors, and investigate responses to infection, we surveyed shoot density, shoot length, epiphyte load, production of plant defenses (phenols), and wasting disease prevalence in eelgrass Zostera marina across 11 sites in the central Salish Sea (Washington state, USA), a region where both wasting disease and eelgrass declines have been documented. Wasting disease was diagnosed by the presence of necrotic lesions, and Labyrinthula cells were identified with histology. Disease prevalence among sites varied from 6 to 79%. The probability of a shoot being diseased was higher in longer shoots, in patches of higher shoot density, and in shoots with higher levels of biofouling from epiphytes. Phenolic concentration was higher in diseased leaves. We hypothesize that this results from the induction of phenols during infection. Additional research is needed to evaluate whether phenols are an adaptive defense against Labyrinthula infection. The high site-level variation in disease prevalence emphasizes the potential for wasting disease to be causing some of the observed decline in eelgrass beds.
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Affiliation(s)
- Maya L Groner
- Centre for Veterinary and Epidemiological Research, Department of Health Management, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, PE C1A 4P3, Canada
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15
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Munkes B, Schubert PR, Karez R, Reusch TBH. Experimental assessment of critical anthropogenic sediment burial in eelgrass Zostera marina. MARINE POLLUTION BULLETIN 2015; 100:144-153. [PMID: 26388446 DOI: 10.1016/j.marpolbul.2015.09.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2015] [Revised: 09/07/2015] [Accepted: 09/08/2015] [Indexed: 06/05/2023]
Abstract
Seagrass meadows, one of the world's most important and productive coastal habitats, are threatened by a range of anthropogenic actions. Burial of seagrass plants due to coastal activities is one important anthropogenic pressure leading to the decline of local populations. In our study, we assessed the response of eelgrass Zostera marina to sediment burial from physiological, morphological, and population parameters. In a full factorial field experiment, burial level (5-20cm) and burial duration (4-16weeks) were manipulated. Negative effects were visible even at the lowest burial level (5cm) and shortest duration (4weeks), with increasing effects over time and burial level. Buried seagrasses showed higher shoot mortality, delayed growth and flowering and lower carbohydrate storage. The observed effects will likely have an impact on next year's survival of buried plants. Our results have implications for the management of this important coastal plant.
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Affiliation(s)
- Britta Munkes
- GEOMAR Helmholtz Center for Ocean Research Kiel, Evolutionary Ecology of Marine Fishes, Düsternbrooker Weg 20, D-24105 Kiel, Germany
| | - Philipp R Schubert
- GEOMAR Helmholtz Center for Ocean Research Kiel, Evolutionary Ecology of Marine Fishes, Düsternbrooker Weg 20, D-24105 Kiel, Germany.
| | - Rolf Karez
- State Agency for Agriculture, Environment, and Rural Areas Schleswig-Holstein (LLUR), Hamburger Chaussee 25, D-24220 Flintbek, Germany
| | - Thorsten B H Reusch
- GEOMAR Helmholtz Center for Ocean Research Kiel, Evolutionary Ecology of Marine Fishes, Düsternbrooker Weg 20, D-24105 Kiel, Germany
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16
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Brakel J, Werner FJ, Tams V, Reusch TBH, Bockelmann AC. Current European Labyrinthula zosterae are not virulent and modulate seagrass (Zostera marina) defense gene expression. PLoS One 2014; 9:e92448. [PMID: 24691450 PMCID: PMC3972160 DOI: 10.1371/journal.pone.0092448] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2013] [Accepted: 02/21/2014] [Indexed: 01/06/2023] Open
Abstract
Pro- and eukaryotic microbes associated with multi-cellular organisms are receiving increasing attention as a driving factor in ecosystems. Endophytes in plants can change host performance by altering nutrient uptake, secondary metabolite production or defense mechanisms. Recent studies detected widespread prevalence of Labyrinthula zosterae in European Zostera marina meadows, a protist that allegedly caused a massive amphi-Atlantic seagrass die-off event in the 1930's, while showing only limited virulence today. As a limiting factor for pathogenicity, we investigated genotype × genotype interactions of host and pathogen from different regions (10-100 km-scale) through reciprocal infection. Although the endophyte rapidly infected Z. marina, we found little evidence that Z. marina was negatively impacted by L. zosterae. Instead Z. marina showed enhanced leaf growth and kept endophyte abundance low. Moreover, we found almost no interaction of protist × eelgrass-origin on different parameters of L. zosterae virulence/Z. marina performance, and also no increase in mortality after experimental infection. In a target gene approach, we identified a significant down-regulation in the expression of 6/11 genes from the defense cascade of Z. marina after real-time quantitative PCR, revealing strong immune modulation of the host's defense by a potential parasite for the first time in a marine plant. Nevertheless, one gene involved in phenol synthesis was strongly up-regulated, indicating that Z. marina plants were probably able to control the level of infection. There was no change in expression in a general stress indicator gene (HSP70). Mean L. zosterae abundances decreased below 10% after 16 days of experimental runtime. We conclude that under non-stress conditions L. zosterae infection in the study region is not associated with substantial virulence.
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Affiliation(s)
- Janina Brakel
- Experimental Ecology – Food webs, Geomar Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
| | - Franziska Julie Werner
- Experimental Ecology – Food webs, Geomar Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
| | - Verena Tams
- Evolutionary Ecology of Marine Fishes, Geomar Helmholtz Centre for Ocean Research Kiel, Germany
| | - Thorsten B. H. Reusch
- Evolutionary Ecology of Marine Fishes, Geomar Helmholtz Centre for Ocean Research Kiel, Germany
| | - Anna-Christina Bockelmann
- Experimental Ecology – Food webs, Geomar Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
- * E-mail:
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Groner ML, Burge CA, Couch CS, Kim CJS, Siegmund GF, Singhal S, Smoot SC, Jarrell A, Gaydos JK, Harvell CD, Wyllie-Echeverria S. Host demography influences the prevalence and severity of eelgrass wasting disease. DISEASES OF AQUATIC ORGANISMS 2014; 108:165-175. [PMID: 24553421 DOI: 10.3354/dao02709] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Many marine pathogens are opportunists, present in the environment, but causing disease only under certain conditions such as immunosuppression due to environmental stress or host factors such as age. In the temperate eelgrass Zostera marina, the opportunistic labyrinthulomycete pathogen Labyrinthula zosterae is present in many populations and occasionally causes severe epidemics of wasting disease; however, risk factors associated with these epidemics are unknown. We conducted both field surveys and experimental manipulations to examine the effect of leaf age (inferred from leaf size) on wasting disease prevalence and severity in Z. marina across sites in the San Juan Archipelago, Washington, USA. We confirmed that lesions observed in the field were caused by active Labyrinthula infections both by identifying the etiologic agent through histology and by performing inoculations with cultures of Labyrinthula spp. isolated from observed lesions. We found that disease prevalence increased at shallower depths and with greater leaf size at all sites, and this effect was more pronounced at declining sites. Experimental inoculations with 2 strains of L. zosterae confirmed an increased susceptibility of older leaves to infection. Overall, this pattern suggests that mature beds and shallow beds of eelgrass may be especially susceptible to outbreaks of wasting disease. The study highlights the importance of considering host and environmental factors when evaluating risk of disease from opportunistic pathogens.
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Affiliation(s)
- Maya L Groner
- Centre for Veterinary and Epidemiological Research, Department of Health Management, Atlantic Veterinary College, University of Prince Edward Island, 550 University Ave., Charlottetown, Prince Edward Island, Canada
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Sullivan BK, Sherman TD, Damare VS, Lilje O, Gleason FH. Potential roles of Labyrinthula spp. in global seagrass population declines. FUNGAL ECOL 2013. [DOI: 10.1016/j.funeco.2013.06.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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