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Renault T, Faury N, Morga B. Propidium monoazide PCR, a method to determine OsHV-1 undamaged capsids and to estimate virus Lethal Dose 50. Virus Res 2024; 340:199307. [PMID: 38160910 PMCID: PMC10800765 DOI: 10.1016/j.virusres.2023.199307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 12/27/2023] [Accepted: 12/28/2023] [Indexed: 01/03/2024]
Abstract
Ostreid herpes virus 1 (OsHV-1) has been classified within the Malacoherpesviridae family from the Herpesvirales order. OsHV-1 is the etiological agent of a contagious viral disease of Pacific oysters, C. gigas, affecting also other bivalve species. Mortality rates reported associated with the viral infection vary considerably between sites and countries and depend on the age of affected stocks. A variant called μVar has been reported since 2008 in Europe and other variants in Australia and in New Zealand last decade. These variants are considered as the main causative agents of mass mortality events affecting C. gigas. Presently there is no established cell line that allows for the detection of infectious OsHV-1. In this context, a technique of propidium monoazide (PMA) PCR was developed in order to quantify "undamaged" capsids. This methodology is of interest to explore the virus infectivity. Being able to quantify viral particles getting an undamaged capsid (not only an amount of viral DNA) in tissue homogenates prepared from infected oysters or in seawater samples can assist in the definition of a Lethal Dose (LD) 50 and gain information in the experiments conducted to reproduce the viral infection. The main objectives of the present study were (i) the development/optimization of a PMA PCR technique for OsHV-1 detection using the best quantity of PMA and verifying its effectiveness through heat treatment, (ii) the definition of the percentage of undamaged capsids in four different tissue homogenates prepared from infected Pacific oysters and (iii) the approach of a LD50 during experimental viral infection assays on the basis of a number of undamaged capsids. Although the developped PMA PCR technique was unable to determine OsHV-1 infectivity in viral supensions, it could greatly improve interpretation of virus positive results obtained by qPCR. This technique is not intended to replace the quantification of viral DNA by qPCR, but it does make it possible to give a form of biological meaning to the detection of this DNA.
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Affiliation(s)
- Tristan Renault
- Département Ressources Biologiques et Environnement, Ifremer, Nantes, France.
| | - Nicole Faury
- ASIM, Adaptation Santé des Invertébrés, Ifremer, La Tremblade, France
| | - Benjamin Morga
- ASIM, Adaptation Santé des Invertébrés, Ifremer, La Tremblade, France
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2
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Gawra J, Valdivieso A, Roux F, Laporte M, de Lorgeril J, Gueguen Y, Saccas M, Escoubas JM, Montagnani C, Destoumieux-Garzόn D, Lagarde F, Leroy MA, Haffner P, Petton B, Cosseau C, Morga B, Dégremont L, Mitta G, Grunau C, Vidal-Dupiol J. Epigenetic variations are more substantial than genetic variations in rapid adaptation of oyster to Pacific oyster mortality syndrome. SCIENCE ADVANCES 2023; 9:eadh8990. [PMID: 37683000 PMCID: PMC10491289 DOI: 10.1126/sciadv.adh8990] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Accepted: 08/09/2023] [Indexed: 09/10/2023]
Abstract
Disease emergence is accelerating with global changes. Understanding by which mechanisms host populations can rapidly adapt will be crucial for management practices. Pacific oyster mortality syndrome (POMS) imposes a substantial and recurrent selective pressure on oyster populations, and rapid adaptation may arise through genetics and epigenetics. In this study, we used (epi)genome-wide association mapping to show that oysters differentially exposed to POMS displayed genetic and epigenetic signatures of selection. Consistent with higher resistance to POMS, the genes targeted included many genes in several pathways related to immunity. By combining correlation, DNA methylation quantitative trait loci, and variance partitioning, we revealed that a third of phenotypic variation was explained by interactions between the genetic and epigenetic information, ~14% by the genome, and up to 25% by the epigenome alone. Similar to genetically based adaptation, epigenetic mechanisms notably governing immune responses can contribute substantially to the rapid adaptation of hosts to emerging infectious diseases.
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Affiliation(s)
- Janan Gawra
- IHPE, Université de Perpignan Via Domitia, CNRS, Ifremer, Université de Montpellier, Perpignan, France
| | - Alejandro Valdivieso
- IHPE, Université de Montpellier, CNRS, Ifremer, Université de Perpignan Via Domitia, Montpellier, France
| | - Fabrice Roux
- LIPME, INRAE, CNRS, Université de Toulouse, Castanet-Tolosan, France
| | - Martin Laporte
- Division de l'expertise sur la faune Aquatique, Ministère des Forêts, de la Faune et des Parcs (MFFP), 880 chemin Sainte-Foy, G1S 4X4 Québec, Québec, Canada
| | - Julien de Lorgeril
- IHPE, Université de Montpellier, CNRS, Ifremer, Université de Perpignan Via Domitia, Montpellier, France
- Ifremer, IRD, Université de la Nouvelle-Calédonie, Université de La Réunion, ENTROPIE, Nouméa, Nouvelle-Calédonie, France
| | - Yannick Gueguen
- IHPE, Université de Montpellier, CNRS, Ifremer, Université de Perpignan Via Domitia, Montpellier, France
- MARBEC, Université de Montpellier, CNRS, Ifremer, IRD, Sète, France
| | - Mathilde Saccas
- IHPE, Université de Montpellier, CNRS, Ifremer, Université de Perpignan Via Domitia, Montpellier, France
| | - Jean-Michel Escoubas
- IHPE, Université de Montpellier, CNRS, Ifremer, Université de Perpignan Via Domitia, Montpellier, France
| | - Caroline Montagnani
- IHPE, Université de Montpellier, CNRS, Ifremer, Université de Perpignan Via Domitia, Montpellier, France
| | | | - Franck Lagarde
- MARBEC, Université de Montpellier, CNRS, Ifremer, IRD, Sète, France
| | - Marc A. Leroy
- IHPE, Université de Montpellier, CNRS, Ifremer, Université de Perpignan Via Domitia, Montpellier, France
| | - Philippe Haffner
- IHPE, Université de Montpellier, CNRS, Ifremer, Université de Perpignan Via Domitia, Montpellier, France
| | - Bruno Petton
- Université de Brest, Ifremer, CNRS, IRD, LEMAR, F-29280 Plouzané, France
| | - Céline Cosseau
- IHPE, Université de Perpignan Via Domitia, CNRS, Ifremer, Université de Montpellier, Perpignan, France
| | - Benjamin Morga
- Ifremer, ASIM, Adaptation Santé des Invertébrés Marins, La Tremblade, France
| | - Lionel Dégremont
- Ifremer, ASIM, Adaptation Santé des Invertébrés Marins, La Tremblade, France
| | - Guillaume Mitta
- IHPE, Université de Perpignan Via Domitia, CNRS, Ifremer, Université de Montpellier, Perpignan, France
- Université de la Polynésie Française, ILM, IRD, Ifremer, F-98719 Tahiti, French Polynesia, France
| | - Christoph Grunau
- IHPE, Université de Perpignan Via Domitia, CNRS, Ifremer, Université de Montpellier, Perpignan, France
| | - Jeremie Vidal-Dupiol
- IHPE, Université de Montpellier, CNRS, Ifremer, Université de Perpignan Via Domitia, Montpellier, France
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3
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Liu OM, Hick PM, Whittington RJ. The Resistance to Lethal Challenge with Ostreid herpesvirus-1 of Pacific Oysters ( Crassostrea gigas) Previously Exposed to This Virus. Viruses 2023; 15:1706. [PMID: 37632048 PMCID: PMC10458589 DOI: 10.3390/v15081706] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Revised: 08/06/2023] [Accepted: 08/07/2023] [Indexed: 08/27/2023] Open
Abstract
Pacific oyster (Crassostrea gigas) aquaculture has been economically impacted in many countries by Pacific oyster mortality syndrome (POMS), a disease initiated by Ostreid herpesvirus 1. The objectives of this study were to determine whether naturally exposed, adult C. gigas could act as reservoirs for OsHV-1 and explain the recurrent seasonal outbreaks of POMS and to test whether or not they were resistant to OsHV-1. In a laboratory infection experiment using thermal shock, OsHV-1 replication was not reactivated within the tissues of such oysters and the virus was not transmitted to naïve cohabitating spat. The adult oysters were resistant to intramuscular injection with a lethal dose of OsHV-1 and had 118 times lower risk of mortality than naïve oysters. Considered together with the results of other studies in C. gigas, natural exposure or laboratory exposure to OsHV-1 may result in immunity during subsequent exposure events, either in the natural environment or the laboratory. While adult C. gigas can carry OsHV-1 infection for lengthy periods, reactivation of viral replication leading to mortality and transmission of the virus to naïve oysters may require specific conditions that were not present in the current experiment. Further investigation is required to evaluate the mechanisms responsible for resistance to disease in oysters previously exposed to OsHV-1, whether immunity can be exploited commercially to prevent POMS outbreaks and to determine the source of the virus for recurrent seasonal outbreaks.
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Affiliation(s)
- Olivia M. Liu
- Sydney School of Veterinary Science, Faculty of Science, The University of Sydney, 425 Werombi Road, Camden, NSW 2570, Australia; (O.M.L.); (P.M.H.)
- Biosecurity Animal Division, Australian Government Department of Agriculture, Fisheries and Forestry, Canberra, ACT 2601, Australia
| | - Paul M. Hick
- Sydney School of Veterinary Science, Faculty of Science, The University of Sydney, 425 Werombi Road, Camden, NSW 2570, Australia; (O.M.L.); (P.M.H.)
- Elizabeth Macarthur Agricultural Institute, Woodbridge Road, Menangle, NSW 2568, Australia
| | - Richard J. Whittington
- Sydney School of Veterinary Science, Faculty of Science, The University of Sydney, 425 Werombi Road, Camden, NSW 2570, Australia; (O.M.L.); (P.M.H.)
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4
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Yao S, Li L, Guan X, He Y, Jouaux A, Xu F, Guo X, Zhang G, Zhang L. Pooled resequencing of larvae and adults reveals genomic variations associated with Ostreid herpesvirus 1 resistance in the Pacific oyster Crassostrea gigas. Front Immunol 2022; 13:928628. [PMID: 36059443 PMCID: PMC9437489 DOI: 10.3389/fimmu.2022.928628] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Accepted: 07/29/2022] [Indexed: 11/30/2022] Open
Abstract
The Ostreid herpesvirus 1 (OsHV-1) is a lethal pathogen of the Pacific oyster (Crassostrea gigas), an important aquaculture species. To understand the genetic architecture of the defense against the pathogen, we studied genomic variations associated with herpesvirus-caused mortalities by pooled whole-genome resequencing of before and after-mortality larval samples as well as dead and surviving adults from a viral challenge. Analysis of the resequencing data identified 5,271 SNPs and 1,883 genomic regions covering 3,111 genes in larvae, and 18,692 SNPs and 28,314 regions covering 4,863 genes in adults that were significantly associated with herpesvirus-caused mortalities. Only 1,653 of the implicated genes were shared by larvae and adults, suggesting that the antiviral response or resistance in larvae and adults involves different sets of genes or differentiated members of expanded gene families. Combined analyses with previous transcriptomic data from challenge experiments revealed that transcription of many mortality-associated genes was also significantly upregulated by herpesvirus infection confirming their importance in antiviral response. Key immune response genes especially those encoding antiviral receptors such as TLRs and RLRs displayed strong association between variation in regulatory region and herpesvirus-caused mortality, suggesting they may confer resistance through transcriptional modulation. These results point to previously undescribed genetic mechanisms for disease resistance at different developmental stages and provide candidate polymorphisms and genes that are valuable for understanding antiviral immune responses and breeding for herpesvirus resistance.
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Affiliation(s)
- Shanshan Yao
- Chinese Academy of Sciences (CAS) and Shandong Province Key Laboratory of Experimental Marine Biology and Center of Deep Sea Research, Center for Ocean Mega-Science, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
- College of Life Sciences, Qingdao University, Qingdao, China
| | - Li Li
- Chinese Academy of Sciences (CAS) and Shandong Province Key Laboratory of Experimental Marine Biology and Center of Deep Sea Research, Center for Ocean Mega-Science, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
- University of Chinese Academy of Sciences, College of Marine Science, Beijing, China
| | - Xudong Guan
- Chinese Academy of Sciences (CAS) and Shandong Province Key Laboratory of Experimental Marine Biology and Center of Deep Sea Research, Center for Ocean Mega-Science, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China
| | - Yan He
- Ministry of Education (MOE) Key Laboratory of Molecular Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Aude Jouaux
- UMR BOREA, “Biologie des Organismes et Ecosystèmes Aquatiques”, MNHN, UPMC, UCBN, CNRS-7208, IRD, Université de Caen Basse-Normandie, Esplanade de la Paix, Caen, France
| | - Fei Xu
- Chinese Academy of Sciences (CAS) and Shandong Province Key Laboratory of Experimental Marine Biology and Center of Deep Sea Research, Center for Ocean Mega-Science, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China
| | - Ximing Guo
- Haskin Shellfish Research Laboratory, Department of Marine and Coastal Sciences, Rutgers University, Port Norris, NJ, United States
- *Correspondence: Ximing Guo, ; Guofan Zhang, ; Linlin Zhang,
| | - Guofan Zhang
- Chinese Academy of Sciences (CAS) and Shandong Province Key Laboratory of Experimental Marine Biology and Center of Deep Sea Research, Center for Ocean Mega-Science, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
- University of Chinese Academy of Sciences, College of Marine Science, Beijing, China
- *Correspondence: Ximing Guo, ; Guofan Zhang, ; Linlin Zhang,
| | - Linlin Zhang
- Chinese Academy of Sciences (CAS) and Shandong Province Key Laboratory of Experimental Marine Biology and Center of Deep Sea Research, Center for Ocean Mega-Science, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
- University of Chinese Academy of Sciences, College of Marine Science, Beijing, China
- *Correspondence: Ximing Guo, ; Guofan Zhang, ; Linlin Zhang,
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5
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Potts RWA, Gutierrez AP, Penaloza CS, Regan T, Bean TP, Houston RD. Potential of genomic technologies to improve disease resistance in molluscan aquaculture. Philos Trans R Soc Lond B Biol Sci 2021; 376:20200168. [PMID: 33813884 PMCID: PMC8059958 DOI: 10.1098/rstb.2020.0168] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/12/2020] [Indexed: 01/04/2023] Open
Abstract
Molluscan aquaculture is a major contributor to global seafood production, but is hampered by infectious disease outbreaks that can cause serious economic losses. Selective breeding has been widely used to improve disease resistance in major agricultural and aquaculture species, and has clear potential in molluscs, albeit its commercial application remains at a formative stage. Advances in genomic technologies, especially the development of cost-efficient genomic selection, have the potential to accelerate genetic improvement. However, tailored approaches are required owing to the distinctive reproductive and life cycle characteristics of molluscan species. Transgenesis and genome editing, in particular CRISPR/Cas systems, have been successfully trialled in molluscs and may further understanding and improvement of genetic resistance to disease through targeted changes to the host genome. Whole-organism genome editing is achievable on a much greater scale compared to other farmed species, making genome-wide CRISPR screening approaches plausible. This review discusses the current state and future potential of selective breeding, genomic tools and genome editing approaches to understand and improve host resistance to infectious disease in molluscs. This article is part of the Theo Murphy meeting issue 'Molluscan genomics: broad insights and future directions for a neglected phylum'.
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Affiliation(s)
- Robert W. A. Potts
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Midlothian EH25 9RG, UK
- Centre for Environment, Fisheries and Aquaculture Science (Cefas), Weymouth Laboratory, Dorset DT4 8UB, UK
| | - Alejandro P. Gutierrez
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Midlothian EH25 9RG, UK
| | - Carolina S. Penaloza
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Midlothian EH25 9RG, UK
| | - Tim Regan
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Midlothian EH25 9RG, UK
| | - Tim P. Bean
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Midlothian EH25 9RG, UK
| | - Ross D. Houston
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Midlothian EH25 9RG, UK
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6
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Leprêtre M, Faury N, Segarra A, Claverol S, Degremont L, Palos-Ladeiro M, Armengaud J, Renault T, Morga B. Comparative Proteomics of Ostreid Herpesvirus 1 and Pacific Oyster Interactions With Two Families Exhibiting Contrasted Susceptibility to Viral Infection. Front Immunol 2021; 11:621994. [PMID: 33537036 PMCID: PMC7848083 DOI: 10.3389/fimmu.2020.621994] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Accepted: 11/30/2020] [Indexed: 12/13/2022] Open
Abstract
Massive mortality outbreaks affecting Pacific oysters (Crassostrea gigas) spat/juveniles are often associated with the detection of a herpesvirus called ostreid herpesvirus type 1 (OsHV-1). In this work, experimental infection trials of C. gigas spat with OsHV-1 were conducted using two contrasted Pacific oyster families for their susceptibility to viral infection. Live oysters were sampled at 12, 26, and 144 h post infection (hpi) to analyze host-pathogen interactions using comparative proteomics. Shotgun proteomics allowed the detection of seven viral proteins in infected oysters, some of them with potential immunomodulatoy functions. Viral proteins were mainly detected in susceptible oysters sampled at 26 hpi, which correlates with the mortality and viral load observed in this oyster family. Concerning the Pacific oyster proteome, more than 3,000 proteins were identified and contrasted proteomic responses were observed between infected A- and P-oysters, sampled at different post-injection times. Gene ontology (GO) and KEGG pathway enrichment analysis performed on significantly modulated proteins uncover the main immune processes (such as RNA interference, interferon-like pathway, antioxidant defense) which contribute to the defense and resistance of Pacific oysters to viral infection. In the more susceptible Pacific oysters, results suggest that OsHV-1 manipulate the molecular machinery of host immune response, in particular the autophagy system. This immunomodulation may lead to weakening and consecutively triggering death of Pacific oysters. The identification of several highly modulated and defense-related Pacific oyster proteins from the most resistant oysters supports the crucial role played by the innate immune system against OsHV-1 and the viral infection. Our results confirm the implication of proteins involved in an interferon-like pathway for efficient antiviral defenses and suggest that proteins involved in RNA interference process prevent viral replication in C. gigas. Overall, this study shows the interest of multi-omic approaches applied on groups of animals with differing sensitivities and provides novel insight into the interaction between Pacific oyster and OsHV-1 with key proteins involved in viral infection resistance.
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Affiliation(s)
- Maxime Leprêtre
- Université de Reims Champagne-Ardenne, UMR-I 02 INERIS-URCA-ULH SEBIO Unité Stress Environnementaux et BIOsurveillance des milieux aquatiques, UFR Sciences Exactes et Naturelles, Campus du Moulin de la Housse, Reims, France
| | - Nicole Faury
- SG2M-LGPMM, Laboratoire De Génétique Et Pathologie Des Mollusques Marins, Ifremer, La Tremblade, France
| | - Amélie Segarra
- Department of Anatomy, Physiology & Cell Biology, School of Veterinary Medicine, University of California, Davis, CA, United States
| | - Stéphane Claverol
- Centre Génomique Fonctionnelle de Bordeaux, Plateforme Protéome, Université de Bordeaux, Bordeaux, France
| | - Lionel Degremont
- SG2M-LGPMM, Laboratoire De Génétique Et Pathologie Des Mollusques Marins, Ifremer, La Tremblade, France
| | - Mélissa Palos-Ladeiro
- Université de Reims Champagne-Ardenne, UMR-I 02 INERIS-URCA-ULH SEBIO Unité Stress Environnementaux et BIOsurveillance des milieux aquatiques, UFR Sciences Exactes et Naturelles, Campus du Moulin de la Housse, Reims, France
| | - Jean Armengaud
- Université Paris-Saclay, CEA, INRAE, DépartementMédicaments et Technologies pour la Santé (DMTS), SPI, Bagnols-sur-Cèze, France
| | - Tristan Renault
- Département Ressources Biologiques Et Environnement, Ifremer, Nantes, France
| | - Benjamin Morga
- SG2M-LGPMM, Laboratoire De Génétique Et Pathologie Des Mollusques Marins, Ifremer, La Tremblade, France
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7
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Friedman CS, Reece KS, Wippel BJT, Agnew MV, Dégremont L, Dhar AK, Kirkland P, MacIntyre A, Morga B, Robison C, Burge CA. Unraveling concordant and varying responses of oyster species to Ostreid Herpesvirus 1 variants. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 739:139752. [PMID: 32846506 DOI: 10.1016/j.scitotenv.2020.139752] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 05/12/2020] [Accepted: 05/25/2020] [Indexed: 06/11/2023]
Abstract
The Ostreid herpesvirus 1 (OsHV-1) and variants, particularly the microvariants (μVars), are virulent and economically devastating viruses impacting oysters. Since 2008 OsHV-1 μVars have emerged rapidly having particularly damaging effects on aquaculture industries in Europe, Australia and New Zealand. We conducted field trials in Tomales Bay (TB), California where a non-μVar strain of OsHV-1 is established and demonstrated differential mortality of naturally exposed seed of three stocks of Pacific oyster, Crassostrea gigas, and one stock of Kumamoto oyster, C. sikamea. Oysters exposed in the field experienced differential mortality that ranged from 64 to 99% in Pacific oysters (Tasmania>Midori = Willapa stocks), which was much higher than that of Kumamoto oysters (25%). Injection trials were done using French (FRA) and Australian (AUS) μVars with the same oyster stocks as planted in the field and, in addition, two stocks of the Eastern oyster, C. virginica. No mortality was observed in control oysters. One C. virginica stock suffered ~10% mortality when challenged with both μVars tested. Two Pacific oyster stocks suffered 75 to 90% mortality, while one C. gigas stock had relatively low mortality when challenged with the AUS μVar (~22%) and higher mortality when challenged with the French μVar (~72%). Conversely, C. sikamea suffered lower mortality when challenged with the French μVar (~22%) and higher mortality with the AUS μVar (~44%). All dead oysters had higher viral loads (~1000×) as measured by quantitative PCR relative to those that survived. However, some survivors had high levels of virus, including those from species with lower mortality. Field mortality in TB correlated with laboratory mortality of the FRA μVar (69% correlation) but not with that of the AUS μVar, which also lacked correlation with the FRA μVar. The variation in response to OsHV-1 variant challenges by oyster species and stocks demonstrates the need for empirical assessment of multiple OsHV-1 variants.
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Affiliation(s)
- Carolyn S Friedman
- School of Aquatic & Fishery Sciences, University of Washington, Box 355020, Seattle, WA 98105, USA
| | - Kimberly S Reece
- Virginia Institute of Marine Sciences, William & Mary, P.O. Box 1346, Gloucester Point, Virginia 23062, USA
| | - Bryanda J T Wippel
- School of Aquatic & Fishery Sciences, University of Washington, Box 355020, Seattle, WA 98105, USA
| | - M Victoria Agnew
- Institute of Marine and Environmental Technology, University of Maryland Baltimore County, 701 E Pratt Street, Baltimore, MD 21202, USA
| | - Lionel Dégremont
- Ifremer, SG2M-LGPMM, Station La Tremblade, 17390 La Tremblade, France
| | - Arun K Dhar
- Aquaculture Pathology Laboratory, Animal and Comparative Biomedical Sciences, The University of Arizona, 1117 E Lowell Road, Tucson, AZ 85721, USA
| | - Peter Kirkland
- Elizabeth Macarthur Agricultural Institute, NSW Department of Primary Industries, Menangle, NSW 2568, Australia
| | - Alanna MacIntyre
- Virginia Institute of Marine Sciences, William & Mary, P.O. Box 1346, Gloucester Point, Virginia 23062, USA
| | - Benjamin Morga
- Ifremer, SG2M-LGPMM, Station La Tremblade, 17390 La Tremblade, France
| | - Clara Robison
- Virginia Institute of Marine Sciences, William & Mary, P.O. Box 1346, Gloucester Point, Virginia 23062, USA
| | - Colleen A Burge
- Institute of Marine and Environmental Technology, University of Maryland Baltimore County, 701 E Pratt Street, Baltimore, MD 21202, USA.
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8
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Robinson AN, Green TJ. Fitness costs associated with maternal immune priming in the oyster. FISH & SHELLFISH IMMUNOLOGY 2020; 103:32-36. [PMID: 32334127 DOI: 10.1016/j.fsi.2020.04.047] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 04/17/2020] [Accepted: 04/20/2020] [Indexed: 06/11/2023]
Abstract
Maternal immune priming is the transfer of immunity from mother to offspring, which may reduce the offspring's risk of disease from a pathogen that previously infected its mother. Maternal immune priming has been described in at least 25 invertebrate taxa, including Crassostrea gigas. Larvae of C. gigas have improved survival to Ostreid herpesvirus (OsHV-1) if their mothers are either infected with OsHV-1 or were injected with a virus mimic called poly(I:C). However, fitness costs associated with maternal immune priming in C. gigas are unknown. Here, we show C. gigas larvae produced from poly(I:C)-treated mothers are smaller, and have higher total bacteria and Vibrio loads compared to control larvae. These results suggest that the improved offspring survival of C. gigas to OsHV-1 due to maternal immune priming with poly(I:C) is potentially traded off with other important life history traits, such as larval growth rate and destabilisation of the microbiome.
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Affiliation(s)
- Andrew N Robinson
- Vancouver Island University, Centre for Shellfish Research, Nanaimo, British Columbia, Canada
| | - Timothy J Green
- Vancouver Island University, Centre for Shellfish Research, Nanaimo, British Columbia, Canada.
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9
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Delmotte J, Chaparro C, Galinier R, de Lorgeril J, Petton B, Stenger PL, Vidal-Dupiol J, Destoumieux-Garzon D, Gueguen Y, Montagnani C, Escoubas JM, Mitta G. Contribution of Viral Genomic Diversity to Oyster Susceptibility in the Pacific Oyster Mortality Syndrome. Front Microbiol 2020; 11:1579. [PMID: 32754139 PMCID: PMC7381293 DOI: 10.3389/fmicb.2020.01579] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Accepted: 06/17/2020] [Indexed: 12/13/2022] Open
Abstract
Juvenile Pacific oysters (Crassostrea gigas) are subjected to recurrent episodes of mass mortalities that constitute a threat for the oyster industry. This mortality syndrome named “Pacific Oyster Mortality Syndrome” (POMS) is a polymicrobial disease whose pathogenesis is initiated by a primary infection by a variant of an Ostreid herpes virus named OsHV-1 μVar. The characterization of the OsHV-1 genome during different disease outbreaks occurring in different geographic areas has revealed the existence of a genomic diversity for OsHV-1 μVar. However, the biological significance of this diversity is still poorly understood. To go further in understanding the consequences of OsHV-1 diversity on POMS, we challenged five biparental families of oysters to two different infectious environments on the French coasts (Atlantic and Mediterranean). We observed that the susceptibility to POMS can be different among families within the same environment but also for the same family between the two environments. Viral diversity analysis revealed that Atlantic and Mediterranean POMS are caused by two distinct viral populations. Moreover, we observed that different oyster families are infected by distinct viral populations within a same infectious environment. Altogether these results suggest that the co-evolutionary processes at play between OsHV-1 μVar and oyster populations have selected a viral diversity that could facilitate the infection process and the transmission in oyster populations. These new data must be taken into account in the development of novel selective breeding programs better adapted to the oyster culture environment.
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Affiliation(s)
- Jean Delmotte
- IHPE, Université de Montpellier, CNRS, Ifremer, Université de Perpignan Via Domitia, Montpellier, France
| | - Cristian Chaparro
- IHPE, Université de Montpellier, CNRS, Ifremer, Université de Perpignan Via Domitia, Montpellier, France
| | - Richard Galinier
- IHPE, Université de Montpellier, CNRS, Ifremer, Université de Perpignan Via Domitia, Montpellier, France
| | - Julien de Lorgeril
- IHPE, Université de Montpellier, CNRS, Ifremer, Université de Perpignan Via Domitia, Montpellier, France
| | - Bruno Petton
- LEMAR UMR 6539, Université de Bretagne Occidentale, CNRS, IRD, Ifremer, Argenton-en-Landunvez, France
| | - Pierre-Louis Stenger
- IHPE, Université de Montpellier, CNRS, Ifremer, Université de Perpignan Via Domitia, Montpellier, France
| | - Jeremie Vidal-Dupiol
- IHPE, Université de Montpellier, CNRS, Ifremer, Université de Perpignan Via Domitia, Montpellier, France
| | | | - Yannick Gueguen
- IHPE, Université de Montpellier, CNRS, Ifremer, Université de Perpignan Via Domitia, Montpellier, France
| | - Caroline Montagnani
- IHPE, Université de Montpellier, CNRS, Ifremer, Université de Perpignan Via Domitia, Montpellier, France
| | - Jean-Michel Escoubas
- IHPE, Université de Montpellier, CNRS, Ifremer, Université de Perpignan Via Domitia, Montpellier, France
| | - Guillaume Mitta
- IHPE, Université de Montpellier, CNRS, Ifremer, Université de Perpignan Via Domitia, Montpellier, France
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10
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Gutierrez AP, Symonds J, King N, Steiner K, Bean TP, Houston RD. Potential of genomic selection for improvement of resistance to ostreid herpesvirus in Pacific oyster (Crassostrea gigas). Anim Genet 2020; 51:249-257. [PMID: 31999002 DOI: 10.1111/age.12909] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/20/2019] [Indexed: 01/15/2023]
Abstract
In genomic selection (GS), genome-wide SNP markers are used to generate genomic estimated breeding values for selection candidates. The application of GS in shellfish looks promising and has the potential to help in dealing with one of the main issues currently affecting Pacific oyster production worldwide, which is the 'summer mortality syndrome'. This causes periodic mass mortality in farms worldwide and has mainly been attributed to a specific variant of the ostreid herpesvirus (OsHV-1). In the current study, we evaluated the potential of genomic selection for host resistance to OsHV-1 in Pacific oysters, and compared it with pedigree-based approaches. An OsHV-1 disease challenge was performed using an immersion-based virus exposure treatment for oysters for 7 days. A total of 768 samples were genotyped using the medium-density SNP array for oysters. A GWAS was performed for the survival trait using a GBLUP approach in blupf90 software. Heritability ranged from 0.25 ± 0.05 to 0.37 ± 0.05 (mean ± SE) based on pedigree and genomic information respectively. Genomic prediction was more accurate than pedigree prediction, and SNP density reduction had little impact on prediction accuracy until marker densities dropped below approximately 500 SNPs. This demonstrates the potential for GS in Pacific oyster breeding programmes, and importantly, demonstrates that a low number of SNPs might suffice to obtain accurate genomic estimated breeding values, thus potentially making the implementation of GS more cost effective.
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Affiliation(s)
- A P Gutierrez
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Midlothian, UK
| | - J Symonds
- Cawthron Institute, 98 Halifax Street East, Nelson, 7010, New Zealand
| | - N King
- Cawthron Institute, 98 Halifax Street East, Nelson, 7010, New Zealand
| | - K Steiner
- Cawthron Institute, 98 Halifax Street East, Nelson, 7010, New Zealand
| | - T P Bean
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Midlothian, UK
| | - R D Houston
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Midlothian, UK
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11
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de Lorgeril J, Petton B, Lucasson A, Perez V, Stenger PL, Dégremont L, Montagnani C, Escoubas JM, Haffner P, Allienne JF, Leroy M, Lagarde F, Vidal-Dupiol J, Gueguen Y, Mitta G. Differential basal expression of immune genes confers Crassostrea gigas resistance to Pacific oyster mortality syndrome. BMC Genomics 2020; 21:63. [PMID: 31959106 PMCID: PMC6971885 DOI: 10.1186/s12864-020-6471-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Accepted: 01/08/2020] [Indexed: 02/08/2023] Open
Abstract
Background As a major threat to the oyster industry, Pacific Oyster Mortality Syndrome (POMS) is a polymicrobial disease affecting the main oyster species farmed across the world. POMS affects oyster juveniles and became panzootic this last decade, but POMS resistance in some oyster genotypes has emerged. While we know some genetic loci associated with resistance, the underlying mechanisms remained uncharacterized. So, we developed a comparative transcriptomic approach using basal gene expression profiles between different oyster biparental families with contrasted phenotypes when confronted to POMS (resistant or susceptible). Results We showed that POMS resistant oysters show differential expression of genes involved in stress responses, protein modifications, maintenance of DNA integrity and repair, and immune and antiviral pathways. We found similarities and clear differences among different molecular pathways in the different resistant families. These results suggest that the resistance process is polygenic and partially varies according to the oyster genotype. Conclusions We found differences in basal expression levels of genes related to TLR-NFκB, JAK-STAT and STING-RLR pathways. These differences could explain the best antiviral response, as well as the robustness of resistant oysters when confronted to POMS. As some of these genes represent valuable candidates for selective breeding, we propose future studies should further examine their function.
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Affiliation(s)
- Julien de Lorgeril
- IHPE, Université de Montpellier, CNRS, Ifremer, Université de Perpignan Via Domitia, Place E. Bataillon, CC080, 34095, Montpellier, France
| | - Bruno Petton
- Ifremer, LEMAR UMR 6539, UBO/CNRS/IRD/Ifremer, 11 presqu'île du vivier, 29840, Argenton-en-Landunvez, France
| | - Aude Lucasson
- IHPE, Université de Montpellier, CNRS, Ifremer, Université de Perpignan Via Domitia, Place E. Bataillon, CC080, 34095, Montpellier, France
| | - Valérie Perez
- IHPE, Université de Montpellier, CNRS, Ifremer, Université de Perpignan Via Domitia, Place E. Bataillon, CC080, 34095, Montpellier, France
| | - Pierre-Louis Stenger
- IHPE, Université de Montpellier, CNRS, Ifremer, Université de Perpignan Via Domitia, Place E. Bataillon, CC080, 34095, Montpellier, France.,Ifremer, UMR 241 Écosystèmes Insulaires Océaniens, Labex Corail, Centre Ifremer du Pacifique, BP 49, 98725, Tahiti, French Polynesia
| | - Lionel Dégremont
- Ifremer, Laboratoire de Génétique et Pathologie des Mollusques Marins, Avenue du Mus de Loup, 17930, La Tremblade, France
| | - Caroline Montagnani
- IHPE, Université de Montpellier, CNRS, Ifremer, Université de Perpignan Via Domitia, Place E. Bataillon, CC080, 34095, Montpellier, France
| | - Jean-Michel Escoubas
- IHPE, Université de Montpellier, CNRS, Ifremer, Université de Perpignan Via Domitia, Place E. Bataillon, CC080, 34095, Montpellier, France
| | - Philippe Haffner
- IHPE, Université de Montpellier, CNRS, Ifremer, Université de Perpignan Via Domitia, Place E. Bataillon, CC080, 34095, Montpellier, France
| | - Jean-François Allienne
- IHPE, Université de Montpellier, CNRS, Ifremer, Université de Perpignan Via Domitia, Place E. Bataillon, CC080, 34095, Montpellier, France
| | - Marc Leroy
- IHPE, Université de Montpellier, CNRS, Ifremer, Université de Perpignan Via Domitia, Place E. Bataillon, CC080, 34095, Montpellier, France
| | - Franck Lagarde
- MARBEC, Université de Montpellier, CNRS, IRD, Ifremer, 87 Avenue Jean Monnet, 34200, Sète, France
| | - Jérémie Vidal-Dupiol
- IHPE, Université de Montpellier, CNRS, Ifremer, Université de Perpignan Via Domitia, Place E. Bataillon, CC080, 34095, Montpellier, France
| | - Yannick Gueguen
- IHPE, Université de Montpellier, CNRS, Ifremer, Université de Perpignan Via Domitia, Place E. Bataillon, CC080, 34095, Montpellier, France
| | - Guillaume Mitta
- IHPE, Université de Montpellier, CNRS, Ifremer, Université de Perpignan Via Domitia, Place E. Bataillon, CC080, 34095, Montpellier, France.
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12
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Divilov K, Schoolfield B, Morga B, Dégremont L, Burge CA, Mancilla Cortez D, Friedman CS, Fleener GB, Dumbauld BR, Langdon C. First evaluation of resistance to both a California OsHV-1 variant and a French OsHV-1 microvariant in Pacific oysters. BMC Genet 2019; 20:96. [PMID: 31830898 PMCID: PMC6909534 DOI: 10.1186/s12863-019-0791-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Accepted: 11/21/2019] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Variants of the Ostreid herpesvirus 1 (OsHV-1) cause high losses of Pacific oysters globally, including in Tomales Bay, California, USA. A suite of new variants, the OsHV-1 microvariants (μvars), cause very high mortalities of Pacific oysters in major oyster-growing regions outside of the United States. There are currently no known Pacific oysters in the United States that are resistant to OsHV-1 as resistance has yet to be evaluated in these oysters. As part of an effort to begin genetic selection for resistance to OsHV-1, 71 families from the Molluscan Broodstock Program, a US West Coast Pacific oyster breeding program, were screened for survival after exposure to OsHV-1 in Tomales Bay. They were also tested in a quarantine laboratory in France where they were exposed to a French OsHV-1 microvariant using a plate assay, with survival recorded from three to seven days post-infection. RESULTS Significant heritability for survival were found for all time points in the plate assay and in the survival phenotype from a single mortality count in Tomales Bay. Genetic correlations between survival against the French OsHV-1 μvar in the plate assay and the Tomales Bay variant in the field trait were weak or non-significant. CONCLUSIONS Future breeding efforts will seek to validate the potential of genetic improvement for survival to OsHV-1 through selection using the Molluscan Broodstock Program oysters. The lack of a strong correlation in survival between OsHV-1 variants under this study's exposure conditions may require independent selection pressure for survival to each variant in order to make simultaneous genetic gains in resistance.
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Affiliation(s)
- Konstantin Divilov
- Department of Fisheries and Wildlife, Coastal Oregon Marine Experiment Station, Oregon State University, Hatfield Marine Science Center, Newport, Oregon USA
| | - Blaine Schoolfield
- Department of Fisheries and Wildlife, Coastal Oregon Marine Experiment Station, Oregon State University, Hatfield Marine Science Center, Newport, Oregon USA
| | - Benjamin Morga
- Laboratoire de Génétique et Pathologie des Mollusques Marins, Ifremer, La Tremblade, France
| | - Lionel Dégremont
- Laboratoire de Génétique et Pathologie des Mollusques Marins, Ifremer, La Tremblade, France
| | - Colleen A. Burge
- Institute of Marine and Environmental Technology, University of Maryland Baltimore County, Baltimore, Maryland USA
| | | | - Carolyn S. Friedman
- School of Aquatic and Fishery Sciences, University of Washington, Seattle, Washington, USA
| | | | - Brett R. Dumbauld
- United States Department of Agriculture-Agricultural Research Service, Hatfield Marine Science Center, Newport, Oregon USA
| | - Chris Langdon
- Department of Fisheries and Wildlife, Coastal Oregon Marine Experiment Station, Oregon State University, Hatfield Marine Science Center, Newport, Oregon USA
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13
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Martenot C, Faury N, Morga B, Degremont L, Lamy JB, Houssin M, Renault T. Exploring First Interactions Between Ostreid Herpesvirus 1 (OsHV-1) and Its Host, Crassostrea gigas: Effects of Specific Antiviral Antibodies and Dextran Sulfate. Front Microbiol 2019; 10:1128. [PMID: 31178841 PMCID: PMC6543491 DOI: 10.3389/fmicb.2019.01128] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Accepted: 05/03/2019] [Indexed: 12/18/2022] Open
Abstract
Viral entry mechanisms of herpesviruses constitute a highly complex process which implicates several viral glycoproteins and different receptors on the host cell surfaces. This initial infection stage was currently undescribed for Ostreid herpes virus 1 (OsHV-1), a herpesvirus infecting bivalves including the Pacific oyster, Crassostrea gigas. To identify OsHV-1 glyproteins implicated in the attachment of the virus to oyster cells, three viral putative membrane proteins, encoded by ORF 25, 41, and 72, were selected and polyclonal antibodies against these targets were used to explore first interactions between the virus and host cells. In addition, effects of dextran sulfate, a negative charged sulfated polysaccharide, were investigated on OsHV-1 infection. Effects of antiviral antibodies and dextran sulfate were evaluated by combining viral DNA and RNA detection in spat (in vivo trials) and in oyster hemolymph (in vitro trials). Results showed that viral protein encoded by ORF 25 appeared to be involved in interaction between OsHV-1 and host cells even if other proteins are likely implicated, such as proteins encoded by ORF 72 and ORF 41. Dextran sulfate at 30 μg/mL significantly reduced the spat mortality rate in the experimental conditions. Taken together, these results contribute to better understanding the pathogenesis of the viral infection, especially during the first stage of OsHV-1 infection, and open the way toward new approaches to control OsHV-1 infection in confined facilities.
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Affiliation(s)
- Claire Martenot
- Institut Français de Recherche pour l'Exploitation de la Mer, Laboratoire de Génétique et Pathologie des Mollusques Marins, La Tremblade, France
| | - Nicole Faury
- Institut Français de Recherche pour l'Exploitation de la Mer, Laboratoire de Génétique et Pathologie des Mollusques Marins, La Tremblade, France
| | - Benjamin Morga
- Institut Français de Recherche pour l'Exploitation de la Mer, Laboratoire de Génétique et Pathologie des Mollusques Marins, La Tremblade, France
| | - Lionel Degremont
- Institut Français de Recherche pour l'Exploitation de la Mer, Laboratoire de Génétique et Pathologie des Mollusques Marins, La Tremblade, France
| | - Jean-Baptiste Lamy
- Institut Français de Recherche pour l'Exploitation de la Mer, Laboratoire de Génétique et Pathologie des Mollusques Marins, La Tremblade, France
| | | | - Tristan Renault
- Département Ressources Biologiques et Environnement, Institut Français de Recherche pour l'Exploitation de la Mer, Nantes, France
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14
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King WL, Siboni N, Williams NLR, Kahlke T, Nguyen KV, Jenkins C, Dove M, O'Connor W, Seymour JR, Labbate M. Variability in the Composition of Pacific Oyster Microbiomes Across Oyster Families Exhibiting Different Levels of Susceptibility to OsHV-1 μvar Disease. Front Microbiol 2019; 10:473. [PMID: 30915058 PMCID: PMC6421512 DOI: 10.3389/fmicb.2019.00473] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Accepted: 02/22/2019] [Indexed: 11/13/2022] Open
Abstract
Oyster diseases are a major impediment to the profitability and growth of the oyster aquaculture industry. In recent years, geographically widespread outbreaks of disease caused by ostreid herpesvirus-1 microvariant (OsHV-1 μvar) have led to mass mortalities among Crassostrea gigas, the Pacific Oyster. Attempts to minimize the impact of this disease have been largely focused on breeding programs, and although these have shown some success in producing oyster families with reduced mortality, the mechanism(s) behind this protection is poorly understood. One possible factor is modification of the C. gigas microbiome. To explore how breeding for resistance to OsHV-1 μvar affects the oyster microbiome, we used 16S rRNA amplicon sequencing to characterize the bacterial communities associated with 35 C. gigas families, incorporating oysters with different levels of susceptibility to OsHV-1 μvar disease. The microbiomes of disease-susceptible families were significantly different to the microbiomes of disease-resistant families. OTUs assigned to the Photobacterium, Vibrio, Aliivibrio, Streptococcus, and Roseovarius genera were associated with low disease resistance. In partial support of this finding, qPCR identified a statistically significant increase of Vibrio-specific 16S rRNA gene copies in the low disease resistance families, possibly indicative of a reduced host immune response to these pathogens. In addition to these results, examination of the core microbiome revealed that each family possessed a small core community, with OTUs assigned to the Winogradskyella genus and the Bradyrhizobiaceae family consistent members across most disease-resistant families. This study examines patterns in the microbiome of oyster families exhibiting differing levels of OsHV-1 μvar disease resistance and reveals some key bacterial taxa that may provide a protective or detrimental role in OsHV-1 μvar disease outbreaks.
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Affiliation(s)
- William L King
- The School of Life Sciences, University of Technology Sydney, Ultimo, NSW, Australia.,Climate Change Cluster, University of Technology Sydney, Ultimo, NSW, Australia
| | - Nachshon Siboni
- Climate Change Cluster, University of Technology Sydney, Ultimo, NSW, Australia
| | - Nathan L R Williams
- The School of Life Sciences, University of Technology Sydney, Ultimo, NSW, Australia
| | - Tim Kahlke
- Climate Change Cluster, University of Technology Sydney, Ultimo, NSW, Australia
| | - Khue Viet Nguyen
- The School of Life Sciences, University of Technology Sydney, Ultimo, NSW, Australia.,Climate Change Cluster, University of Technology Sydney, Ultimo, NSW, Australia
| | - Cheryl Jenkins
- NSW Department of Primary Industries, Elizabeth Macarthur Agricultural Institute, Menangle, NSW, Australia
| | - Michael Dove
- NSW Department of Primary Industries, Port Stephens Fisheries Institute, Port Stephens, NSW, Australia
| | - Wayne O'Connor
- NSW Department of Primary Industries, Port Stephens Fisheries Institute, Port Stephens, NSW, Australia
| | - Justin R Seymour
- Climate Change Cluster, University of Technology Sydney, Ultimo, NSW, Australia
| | - Maurizio Labbate
- The School of Life Sciences, University of Technology Sydney, Ultimo, NSW, Australia
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15
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Lafont M, Goncalves P, Guo X, Montagnani C, Raftos D, Green T. Transgenerational plasticity and antiviral immunity in the Pacific oyster (Crassostrea gigas) against Ostreid herpesvirus 1 (OsHV-1). DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2019; 91:17-25. [PMID: 30278186 DOI: 10.1016/j.dci.2018.09.022] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Revised: 09/03/2018] [Accepted: 09/26/2018] [Indexed: 06/08/2023]
Abstract
The oyster's immune system is capable of adapting upon exposure to a pathogen-associated molecular pattern (PAMP) to have an enhanced secondary response against the same type of pathogen. This has been demonstrated using poly(I:C) to elicit an antiviral response in the Pacific oyster (Crassostrea gigas) against Ostreid herpesvirus (OsHV-1). Improved survival following exposure to poly(I:C) has been found in later life stages (within-generational immune priming) and in the next generation (transgenerational immune priming). The mechanism that the oyster uses to transfer immunity to the next generation is unknown. Here we show that oyster larvae have higher survival to OsHV-1 when their mothers, but not their fathers, are exposed to poly(I:C) prior to spawning. RNA-seq provided no evidence to suggest that parental exposure to poly(I:C) reconfigures antiviral gene expression in unchallenged larvae. We conclude that the improved survival of larvae might occur via maternal provisioning of antiviral compounds in the eggs.
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Affiliation(s)
- Maxime Lafont
- Sydney Institute of Marine Science, Chowder Bay, Sydney, Australia; IHPE, Université de Montpellier, CNRS, Ifremer, Université de Perpignan Via Domitia, France
| | - Priscila Goncalves
- Sydney Institute of Marine Science, Chowder Bay, Sydney, Australia; Macquarie University, Department of Biological Sciences, Sydney, Australia
| | - Ximing Guo
- Haskin Shellfish Research Laboratory, Rutgers University, Port Norris, NJ, USA
| | - Caroline Montagnani
- IHPE, Université de Montpellier, CNRS, Ifremer, Université de Perpignan Via Domitia, France
| | - David Raftos
- Sydney Institute of Marine Science, Chowder Bay, Sydney, Australia; Macquarie University, Department of Biological Sciences, Sydney, Australia
| | - Timothy Green
- Sydney Institute of Marine Science, Chowder Bay, Sydney, Australia; Macquarie University, Department of Biological Sciences, Sydney, Australia.
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16
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Lachnit T, Dafforn KA, Johnston EL, Steinberg P. Contrasting distributions of bacteriophages and eukaryotic viruses from contaminated coastal sediments. Environ Microbiol 2018; 21:1929-1941. [PMID: 29971921 DOI: 10.1111/1462-2920.14340] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Revised: 06/20/2018] [Accepted: 06/24/2018] [Indexed: 12/21/2022]
Abstract
Viruses are ubiquitous, abundant and play an important role in all ecosystems. Here, we advance understanding of coastal sediment viruses by exploring links in the composition and abundance of sediment viromes to environmental stressors and sediment bacterial communities. We collected sediment from contaminated and reference sites in Sydney Harbour and used metagenomics to analyse viral community composition. The proportion of phages at contaminated sites was significantly greater than phages at reference sites, whereas eukaryotic viruses were relatively more abundant at reference sites. We observed shifts in viral and bacterial composition between contaminated and reference sites of a similar magnitude. Models based on sediment characteristics revealed that total organic carbon in the sediments explained most of the environmental stress-related variation in the viral dataset. Our results suggest that the presence of anthropogenic contaminants in coastal sediments could be influencing viral community composition with potential consequences for associated hosts and the environment.
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Affiliation(s)
- Tim Lachnit
- Zoological Institute, Christian-Albrechts-University Kiel, 24118, Kiel, Germany.,Centre for Marine Bio-Innovation, School of BEES, University of New South Wales, Sydney, New South Wales, 2052, Australia
| | - Katherine A Dafforn
- Applied Marine and Estuarine Ecology Lab, School of BEES, University of New South Wales, Sydney, New South Wales, 2052, Australia.,Sydney Institute of Marine Science, Mosman, New South Wales, 2088, Australia
| | - Emma L Johnston
- Applied Marine and Estuarine Ecology Lab, School of BEES, University of New South Wales, Sydney, New South Wales, 2052, Australia.,Sydney Institute of Marine Science, Mosman, New South Wales, 2088, Australia
| | - Peter Steinberg
- Centre for Marine Bio-Innovation, School of BEES, University of New South Wales, Sydney, New South Wales, 2052, Australia.,Sydney Institute of Marine Science, Mosman, New South Wales, 2088, Australia.,Singapore Centre on Life Science Engineering, Nanyang Technological University, Singapore
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17
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Moreira R, Pereiro P, Balseiro P, Milan M, Pauletto M, Bargelloni L, Novoa B, Figueras A. Revealing Mytilus galloprovincialis transcriptomic profiles during ontogeny. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2018; 84:292-306. [PMID: 29481906 DOI: 10.1016/j.dci.2018.01.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Revised: 01/22/2018] [Accepted: 01/23/2018] [Indexed: 06/08/2023]
Abstract
Mediterranean mussels are a worldwide spread bivalve species with extraordinary biological success. One of the reasons of this success could be the reproduction strategy of bivalves, characterized by the presence of trochophore larvae. Larval development in bivalves has been a topic of raising interest in the scientific community but it deserves much more attention. The principal objective of this work was to study the transcriptomic profile of the ontogeny of Mytilus galloprovincialis analyzing the gene expression in different developmental stages, from oocytes to juveniles. For this purpose, after conducting a 454 sequencing of the transcriptomes of mussel hemocytes, adult tissues and larvae, a new DNA microarray was designed and developed. The studied developmental stages: unfertilized oocytes, veliger, pediveliger, settled larvae and juveniles, showed very different transcriptomic profiles and clustered in groups defining their characteristic gene expression along ontogeny. Our results show that oocytes present a distinct and characteristic transcriptome. After metamorphosis, both settled larvae and juveniles showed a very similar transcriptome, with no enriched GO terms found between these two stages. This suggests: 1.- the progressive loss of RNA of maternal origin through larval development and 2.- the stabilization of the gene expression after settlement. On the other hand during metamorphosis a specific profile of differentially expressed genes was found. These genes were related to processes such as differentiation and biosynthesis. Processes related to the immune response were strongly down regulated. These suggest a development commitment at the expense of other non-essential functions, which are temporary set aside. Immune genes such as antimicrobial peptides suffer a decreased expression during metamorphosis. In fact, we found that the oocytes which express a higher quantity of genes such as myticins are more likely to reach success of the offspring, compared to oocytes poor in such mRNAs, whose progeny died before reaching metamorphosis.
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Affiliation(s)
- Rebeca Moreira
- Instituto de Investigaciones Marinas, IIM - CSIC, Eduardo Cabello, 6, 36208 Vigo, Spain.
| | - Patricia Pereiro
- Instituto de Investigaciones Marinas, IIM - CSIC, Eduardo Cabello, 6, 36208 Vigo, Spain.
| | - Pablo Balseiro
- Instituto de Investigaciones Marinas, IIM - CSIC, Eduardo Cabello, 6, 36208 Vigo, Spain; Uni Research Environment, Uni Research AS, Nygårdsgaten 112, 5008 Bergen, Norway.
| | - Massimo Milan
- Department of Comparative Biomedicine and Food Science (BCA) University of Padova, Viale dell'Università 16, 35020 Legnaro, Italy.
| | - Marianna Pauletto
- Department of Comparative Biomedicine and Food Science (BCA) University of Padova, Viale dell'Università 16, 35020 Legnaro, Italy.
| | - Luca Bargelloni
- Department of Comparative Biomedicine and Food Science (BCA) University of Padova, Viale dell'Università 16, 35020 Legnaro, Italy.
| | - Beatriz Novoa
- Instituto de Investigaciones Marinas, IIM - CSIC, Eduardo Cabello, 6, 36208 Vigo, Spain.
| | - Antonio Figueras
- Instituto de Investigaciones Marinas, IIM - CSIC, Eduardo Cabello, 6, 36208 Vigo, Spain.
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A Genome-Wide Association Study for Host Resistance to Ostreid Herpesvirus in Pacific Oysters ( Crassostrea gigas). G3-GENES GENOMES GENETICS 2018; 8:1273-1280. [PMID: 29472307 PMCID: PMC5873916 DOI: 10.1534/g3.118.200113] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Ostreid herpesvirus (OsHV) can cause mass mortality events in Pacific oyster aquaculture. While various factors impact on the severity of outbreaks, it is clear that genetic resistance of the host is an important determinant of mortality levels. This raises the possibility of selective breeding strategies to improve the genetic resistance of farmed oyster stocks, thereby contributing to disease control. Traditional selective breeding can be augmented by use of genetic markers, either via marker-assisted or genomic selection. The aim of the current study was to investigate the genetic architecture of resistance to OsHV in Pacific oyster, to identify genomic regions containing putative resistance genes, and to inform the use of genomics to enhance efforts to breed for resistance. To achieve this, a population of ∼1,000 juvenile oysters were experimentally challenged with a virulent form of OsHV, with samples taken from mortalities and survivors for genotyping and qPCR measurement of viral load. The samples were genotyped using a recently-developed SNP array, and the genotype data were used to reconstruct the pedigree. Using these pedigree and genotype data, the first high density linkage map was constructed for Pacific oyster, containing 20,353 SNPs mapped to the ten pairs of chromosomes. Genetic parameters for resistance to OsHV were estimated, indicating a significant but low heritability for the binary trait of survival and also for viral load measures (h2 0.12 – 0.25). A genome-wide association study highlighted a region of linkage group 6 containing a significant QTL affecting host resistance. These results are an important step toward identification of genes underlying resistance to OsHV in oyster, and a step toward applying genomic data to enhance selective breeding for disease resistance in oyster aquaculture.
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Green TJ, Speck P. Antiviral Defense and Innate Immune Memory in the Oyster. Viruses 2018; 10:v10030133. [PMID: 29547519 PMCID: PMC5869526 DOI: 10.3390/v10030133] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Revised: 03/06/2018] [Accepted: 03/14/2018] [Indexed: 12/17/2022] Open
Abstract
The Pacific oyster, Crassostrea gigas, is becoming a valuable model for investigating antiviral defense in the Lophotrochozoa superphylum. In the past five years, improvements to laboratory-based experimental infection protocols using Ostreid herpesvirus I (OsHV-1) from naturally infected C. gigas combined with next-generation sequencing techniques has revealed that oysters have a complex antiviral response involving the activation of all major innate immune pathways. Experimental evidence indicates C. gigas utilizes an interferon-like response to limit OsHV-1 replication and spread. Oysters injected with a viral mimic (polyI:C) develop resistance to OsHV-1. Improved survival following polyI:C injection was found later in life (within-generational immune priming) and in the next generation (multi-generational immune priming). These studies indicate that the oyster's antiviral defense system exhibits a form of innate immune-memory. An important priority is to identify the molecular mechanisms responsible for this phenomenon. This knowledge will motivate the development of practical and cost-effective treatments for improving oyster health in aquaculture.
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Affiliation(s)
- Timothy J Green
- Centre for Shellfish Research & Department of Fisheries and Aquaculture, Vancouver Island University, Nanaimo, BC V9R 5S5, Canada.
- Department of Biological Sciences, Macquarie University, Sydney, NSW 2109, Australia.
| | - Peter Speck
- College of Science and Engineering, Flinders University, GPO Box 2100, Adelaide, SA 5001, Australia.
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20
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Brokordt K, González R, Farías W, Winkler FE, Lohrmann KB. First insight into the heritable variation of the resistance to infection with the bacteria causing the withering syndrome disease in Haliotis rufescens abalone. J Invertebr Pathol 2017; 150:15-20. [PMID: 28870439 DOI: 10.1016/j.jip.2017.08.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2016] [Revised: 08/22/2017] [Accepted: 08/25/2017] [Indexed: 11/17/2022]
Abstract
Withering syndrome disease has experienced worldwide spread in the last decade. This fatal disease for abalone is produced by a rickettsia-like organism (WS-RLO), the bacterium "Candidatus Xenohaliotis californiensis". To evaluate the potential of the red abalone (Haliotis rufescens) to improve its resistance to infection by WS-RLO, the additive genetic component in the variation of this trait was estimated. For this, the variation in infection intensity with WS-RLOs and WS-RLOv (phage-infected RLOs) was analyzed in 56 families of full-sibs maintained for three years in a host-parasite cohabitation aquaculture system. A WS-RLO prevalence of 65% was observed in the analysed population; and from the total WS-RLO inclusions 60% were hyperparasited with the phage (WS-RLOv). The decrease in the food ingestion rate was the sole negative effect associated with increasing WS-RLO intensity of infection, suggesting that the high level of WS-RLOv load may have diminished the symptoms of WS disease in the analyzed abalones. The estimated heritabilities were moderate to mid, but significant, varying from 0.21 to 0.23 and 0.36 for WS-RLO and WS-RLOv infections, respectively. This suggests that variation in resistance to infection with WS-RLO may respond to selection in the evaluated red abalone population. Estimated response to selection (G) for the level of infection by WS-RLO indicated that if the 10% of red abalone with the lowest infection level is selected as broodstock, a 90% reduction in the intensity of infection in the progeny can be expected, even with the lowest estimation of heritability (h2=0.21). This strong response would be also due to the large phenotypic variance of this trait. Strong positive correlations, both phenotypic and genotypic, were observed between infection intensities with WS-RLO and WS-RLOv, indicating that selection to increase resistance to one of the types of RLOs will affect resistance in the other in the same direction. This is the first study that demonstrates the existence of additive genetic variation for resistance to WS-RLO in abalone. Consequently, it is possible to increase the resistance to WS-RLO in H. rufescens by selective breeding, which can be an economically attractive and environmentally friendly manner to reduce mortalities and growth effects caused by WS in abalone farms.
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Affiliation(s)
- Katherina Brokordt
- Laboratorio de Fisiología y Genética Marina (FIGEMA), Centro de Estudios Avanzados en Zonas Áridas (CEAZA) & Universidad Católica del Norte, 1781421 Coquimbo, Chile.
| | - Roxana González
- Laboratorio de Fisiología y Genética Marina (FIGEMA), Centro de Estudios Avanzados en Zonas Áridas (CEAZA) & Universidad Católica del Norte, 1781421 Coquimbo, Chile; Programa de Magister en Ciencia del Mar mención Recursos Costeros, Facultad de Ciencias del Mar, Universidad Católica del Norte, 1781421 Coquimbo, Chile.
| | - William Farías
- Laboratorio de Fisiología y Genética Marina (FIGEMA), Centro de Estudios Avanzados en Zonas Áridas (CEAZA) & Universidad Católica del Norte, 1781421 Coquimbo, Chile; Programa de Magister en Ciencia del Mar mención Recursos Costeros, Facultad de Ciencias del Mar, Universidad Católica del Norte, 1781421 Coquimbo, Chile.
| | - Federico E Winkler
- Departamento de Biología Marina, Facultad de Ciencias del Mar, Universidad Católica del Norte, 1781421 Coquimbo, Chile; Laboratorio de Fisiología y Genética Marina (FIGEMA), Centro de Estudios Avanzados en Zonas Áridas (CEAZA) & Universidad Católica del Norte, 1781421 Coquimbo, Chile.
| | - Karin B Lohrmann
- Departamento de Biología Marina, Facultad de Ciencias del Mar, Universidad Católica del Norte, 1781421 Coquimbo, Chile.
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21
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Deines P, Lachnit T, Bosch TCG. Competing forces maintain theHydrametaorganism. Immunol Rev 2017; 279:123-136. [DOI: 10.1111/imr.12564] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Peter Deines
- Zoological Institute; Christian Albrechts University Kiel; Kiel Germany
| | - Tim Lachnit
- Zoological Institute; Christian Albrechts University Kiel; Kiel Germany
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22
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Young T, Kesarcodi-Watson A, Alfaro AC, Merien F, Nguyen TV, Mae H, Le DV, Villas-Bôas S. Differential expression of novel metabolic and immunological biomarkers in oysters challenged with a virulent strain of OsHV-1. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2017; 73:229-245. [PMID: 28373065 DOI: 10.1016/j.dci.2017.03.025] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2016] [Revised: 03/30/2017] [Accepted: 03/30/2017] [Indexed: 06/07/2023]
Abstract
Early lifestages of the Pacific oyster (Crassostrea gigas) are highly susceptible to infection by OsHV-1 μVar, but little information exists regarding metabolic or pathophysiological responses of larval hosts. Using a metabolomics approach, we identified a range of metabolic and immunological responses in oyster larvae exposed to OsHV-1 μVar; some of which have not previously been reported in molluscs. Multivariate analyses of entire metabolite profiles were able to separate infected from non-infected larvae. Correlation analysis revealed the presence of major perturbations in the underlying biochemical networks and secondary pathway analysis of functionally-related metabolites identified a number of prospective pathways differentially regulated in virus-exposed larvae. These results provide new insights into the pathogenic mechanisms of OsHV-1 infection in oyster larvae, which may be applied to develop disease mitigation strategies and/or as new phenotypic information for selective breeding programmes aiming to enhance viral resistance.
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Affiliation(s)
- Tim Young
- Institute for Applied Ecology New Zealand, School of Science, Faculty of Health and Environmental Sciences, Auckland University of Technology, Private Bag 92006, Auckland 1142, New Zealand; Metabolomics Laboratory, School of Biological Sciences, The University of Auckland, Private Bag 92019, Auckland Mail Centre, Auckland 1142, New Zealand
| | | | - Andrea C Alfaro
- Institute for Applied Ecology New Zealand, School of Science, Faculty of Health and Environmental Sciences, Auckland University of Technology, Private Bag 92006, Auckland 1142, New Zealand.
| | - Fabrice Merien
- AUT-Roche Diagnostics Laboratory, School of Science, Faculty of Health and Environmental Sciences, Auckland University of Technology, Private Bag 92006, Auckland 1142, New Zealand
| | - Thao V Nguyen
- Institute for Applied Ecology New Zealand, School of Science, Faculty of Health and Environmental Sciences, Auckland University of Technology, Private Bag 92006, Auckland 1142, New Zealand
| | - Hannah Mae
- Cawthron Institute, 98 Halifax Street East, Private Bag 2, Nelson 7042, New Zealand
| | - Dung V Le
- Institute for Applied Ecology New Zealand, School of Science, Faculty of Health and Environmental Sciences, Auckland University of Technology, Private Bag 92006, Auckland 1142, New Zealand
| | - Silas Villas-Bôas
- Metabolomics Laboratory, School of Biological Sciences, The University of Auckland, Private Bag 92019, Auckland Mail Centre, Auckland 1142, New Zealand
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23
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Travers MA, Tourbiez D, Parizadeh L, Haffner P, Kozic-Djellouli A, Aboubaker M, Koken M, Dégremont L, Lupo C. Several strains, one disease: experimental investigation of Vibrio aestuarianus infection parameters in the Pacific oyster, Crassostrea gigas. Vet Res 2017; 48:32. [PMID: 28549482 PMCID: PMC5446674 DOI: 10.1186/s13567-017-0438-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Accepted: 05/04/2017] [Indexed: 01/20/2023] Open
Abstract
This study investigated oyster infection dynamics by different strains of Vibrio aestuarianus isolated before and after the apparent re-emergence of this pathogen observed in France in 2011. We conducted experiments to compare minimal infective dose, lethal dose 50 and bacterial shedding for six V. aestuarianus strains. Whatever the strain used, mortality was induced in juvenile oysters by intramuscular injection and reached 90–100% of mortality within 5 days. Moreover, bacterial shedding was comparable among strains and reached its maximum after 20 h (≈10 EXP5 bacteria/mL/animal). Similarly, our first estimations of lethal dose 50 were comparable among strains (minimal infective dose around 0.4 × 10EXP5 bacteria/mL and LD50 around 10EXP5 bacteria/mL) by using seawater containing freshly shed bacteria. These results indicate that, at least with these criteria, despite V. aestuarianus strains genetic diversity, the disease process is similar. The strains isolated after the apparent re-emergence of the bacteria in 2011, do not present a more acute virulence phenotype than the reference strains isolated between 2002 and 2007. Finally, our study provides original and noteworthy data indicating that infected oysters shed bacteria at a level above the threshold of LD50 a few days before they die, meaning that infection is expected to spread in a susceptible population.
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Affiliation(s)
- Marie-Agnès Travers
- IFREMER, SG2M-LGPMM, Laboratoire de Génétique et Pathologie des Mollusques Marins, Avenue de Mus de Loup, 17390, La Tremblade, France.
| | - Delphine Tourbiez
- IFREMER, SG2M-LGPMM, Laboratoire de Génétique et Pathologie des Mollusques Marins, Avenue de Mus de Loup, 17390, La Tremblade, France
| | - Leïla Parizadeh
- IFREMER, SG2M-LGPMM, Laboratoire de Génétique et Pathologie des Mollusques Marins, Avenue de Mus de Loup, 17390, La Tremblade, France
| | - Philippe Haffner
- IFREMER, SG2M-LGPMM, Laboratoire de Génétique et Pathologie des Mollusques Marins, Avenue de Mus de Loup, 17390, La Tremblade, France.,Interactions Hôtes-Pathogènes-Environnements (IHPE), UMR 5244, CNRS, IFREMER, Université de Perpignan Via Domitia, Université de Montpellier, 34095, Montpellier, France
| | - Angélique Kozic-Djellouli
- IFREMER, SG2M-LGPMM, Laboratoire de Génétique et Pathologie des Mollusques Marins, Avenue de Mus de Loup, 17390, La Tremblade, France
| | | | - Marcel Koken
- LABOCEA-CNRS, 120 Avenue Alexis de Rochon, 29280, Plouzané, France
| | - Lionel Dégremont
- IFREMER, SG2M-LGPMM, Laboratoire de Génétique et Pathologie des Mollusques Marins, Avenue de Mus de Loup, 17390, La Tremblade, France
| | - Coralie Lupo
- IFREMER, SG2M-LGPMM, Laboratoire de Génétique et Pathologie des Mollusques Marins, Avenue de Mus de Loup, 17390, La Tremblade, France
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24
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Azéma P, Lamy JB, Boudry P, Renault T, Travers MA, Dégremont L. Genetic parameters of resistance to Vibrio aestuarianus, and OsHV-1 infections in the Pacific oyster, Crassostrea gigas, at three different life stages. Genet Sel Evol 2017; 49:23. [PMID: 28201985 PMCID: PMC5311879 DOI: 10.1186/s12711-017-0297-2] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2016] [Accepted: 02/08/2017] [Indexed: 12/11/2022] Open
Abstract
Background In France, two main diseases threaten Pacific oyster production. Since 2008, Crassostrea gigas spat have suffered massive losses due to the ostreid herpesvirus OsHV-1, and since 2012, significant mortalities in commercial-size adults have been related to infection by the bacterium Vibrio aestuarianus. The genetic basis for resistance to V. aestuarianus and OsHV-1 and the nature of the genetic correlation between these two traits were investigated by using 20 half-sib sire families, each containing two full-sib families. For each disease, controlled infectious challenges were conducted using naïve oysters that were 3 to 26 months old. In addition, siblings were tested under field, pond and raceway conditions to determine whether laboratory trials reflected mortality events that occur in the oyster industry. Results First, we estimated the genetic basis of resistance to V. aestuarianus in C. gigas. Susceptibility to the infection was low for oysters in spat stage but increased with later life stages. Second, we confirmed a strong genetic basis of resistance to OsHV-1 infection at early stages and demonstrated that it was also strong at later stages. Most families had increased resistance to OsHV-1 infection from the spat to adult stages, while others consistently showed low or high mortality rates related to OsHV-1 infection, regardless of the life stage. Our third main finding was the absence of genetic correlations between resistance to OsHV-1 infection and resistance to V. aestuarianus infection. Conclusions Selective breeding to enhance resistance to OsHV-1 infection could be achieved through selective breeding at early stages and would not affect resistance to V. aestuarianus infection. However, our results suggest that the potential to select for improved resistance to V. aestuarianus is lower. Selection for dual resistance to OsHV-1 and V. aestuarianus infection in C. gigas might reduce the impact of these two major diseases by selecting families that have the highest breeding values for resistance to both diseases. Electronic supplementary material The online version of this article (doi:10.1186/s12711-017-0297-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Patrick Azéma
- Laboratoire de Génétique et Pathologie des Mollusques Marins, Ifremer, avenue Mus de Loup, 17390, La Tremblade, France
| | - Jean-Baptiste Lamy
- Laboratoire de Génétique et Pathologie des Mollusques Marins, Ifremer, avenue Mus de Loup, 17390, La Tremblade, France
| | - Pierre Boudry
- Laboratoire des Sciences de l'Environnement Marin, UMR 6539 LEMAR (UBO/CNRS/IRD/Ifremer), Centre de Bretagne, Ifremer, CS 10070, 29280, Plouzané, France
| | - Tristan Renault
- Département Ressources Biologique et Environnement, Ifremer, Rue de l'Ile d'Yeu, 44300, Nantes, France
| | - Marie-Agnès Travers
- Laboratoire de Génétique et Pathologie des Mollusques Marins, Ifremer, avenue Mus de Loup, 17390, La Tremblade, France
| | - Lionel Dégremont
- Laboratoire de Génétique et Pathologie des Mollusques Marins, Ifremer, avenue Mus de Loup, 17390, La Tremblade, France.
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25
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Arzul I, Corbeil S, Morga B, Renault T. Viruses infecting marine molluscs. J Invertebr Pathol 2017; 147:118-135. [PMID: 28189502 DOI: 10.1016/j.jip.2017.01.009] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Revised: 01/20/2017] [Accepted: 01/23/2017] [Indexed: 11/19/2022]
Abstract
Although a wide range of viruses have been reported in marine molluscs, most of these reports rely on ultrastructural examination and few of these viruses have been fully characterized. The lack of marine mollusc cell lines restricts virus isolation capacities and subsequent characterization works. Our current knowledge is mostly restricted to viruses affecting farmed species such as oysters Crassostrea gigas, abalone Haliotis diversicolor supertexta or the scallop Chlamys farreri. Molecular approaches which are needed to identify virus affiliation have been carried out for a small number of viruses, most of them belonging to the Herpesviridae and birnaviridae families. These last years, the use of New Generation Sequencing approach has allowed increasing the number of sequenced viral genomes and has improved our capacity to investigate the diversity of viruses infecting marine molluscs. This new information has in turn allowed designing more efficient diagnostic tools. Moreover, the development of experimental infection protocols has answered some questions regarding the pathogenesis of these viruses and their interactions with their hosts. Control and management of viral diseases in molluscs mostly involve active surveillance, implementation of effective bio security measures and development of breeding programs. However factors triggering pathogen development and the life cycle and status of the viruses outside their mollusc hosts still need further investigations.
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Affiliation(s)
- Isabelle Arzul
- Ifremer, SG2M-LGPMM, Station La Tremblade, 17390 La Tremblade, France
| | - Serge Corbeil
- CSIRO Australian Animal Health Laboratory, 5 Portarlington Road, Geelong East, Victoria 3220, Australia
| | - Benjamin Morga
- Ifremer, SG2M-LGPMM, Station La Tremblade, 17390 La Tremblade, France
| | - Tristan Renault
- Ifremer, RBE, Centre Atlantique, Rue de l'Ile d'Yeu, BP 21105, 44311 Nantes Cedex 03, France.
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26
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Pernet F, Lupo C, Bacher C, Whittington RJ. Infectious diseases in oyster aquaculture require a new integrated approach. Philos Trans R Soc Lond B Biol Sci 2016; 371:rstb.2015.0213. [PMID: 26880845 DOI: 10.1098/rstb.2015.0213] [Citation(s) in RCA: 87] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Emerging diseases pose a recurrent threat to bivalve aquaculture. Recently, massive mortality events in the Pacific oyster Crassostrea gigas associated with the detection of a microvariant of the ostreid herpesvirus 1 (OsHV-1µVar) have been reported in Europe, Australia and New Zealand. Although the spread of disease is often viewed as a governance failure, we suggest that the development of protective measures for bivalve farming is presently held back by the lack of key scientific knowledge. In this paper, we explore the case for an integrated approach to study the management of bivalve disease, using OsHV-1 as a case study. Reconsidering the key issues by incorporating multidisciplinary science could provide a holistic understanding of OsHV-1 and increase the benefit of research to policymakers.
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Affiliation(s)
- Fabrice Pernet
- UMR LEMAR 6539 (UBO/CNRS/IRD/Ifremer), Ifremer, Technopôle Brest Iroise, BP 70, Plouzané 29280, France
| | - Coralie Lupo
- Laboratoire de Génétique et Pathologie des Mollusques Marins, Ifremer-SG2M-LGPMM, Avenue Mus de Loup, La Tremblade 17390, France
| | - Cédric Bacher
- Dyneco/BENTHOS, Ifremer, Technopôle Brest Iroise, BP 70, Plouzané 29280, France
| | - Richard J Whittington
- Faculty of Veterinary Science, The University of Sydney, 425 Werombi Road, Camden, New South Wales 2570, Australia
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27
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Prado-Alvarez M, Darmody G, Hutton S, O'Reilly A, Lynch SA, Culloty SC. Occurrence of OsHV-1 in Crassostrea gigas Cultured in Ireland during an Exceptionally Warm Summer. Selection of Less Susceptible Oysters. Front Physiol 2016; 7:492. [PMID: 27877131 PMCID: PMC5099240 DOI: 10.3389/fphys.2016.00492] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2016] [Accepted: 10/11/2016] [Indexed: 11/13/2022] Open
Abstract
The occurrence of OsHV-1, a herpes virus causing mass mortality in the Pacific oyster Crassostrea gigas was investigated with the aim to select individuals with different susceptibility to the infection. Naïve spat transferred to infected areas and juveniles currently being grown at those sites were analyzed using molecular and histology approaches. The survey period distinguishes itself by very warm temperatures reaching up to 3.5°C above the average. The virus was not detected in the virus free area although a spread of the disease could be expected due to high temperatures. Overall mortality, prevalence of infection and viral load was higher in spat confirming the higher susceptibility in early life stages. OsHV-1 and oyster mortality were detected in naïve spat after 15 days of cohabitation with infected animals. Although, infection was associated with mortality in spat, the high seawater temperatures could also be the direct cause of mortality at the warmest site. One stock of juveniles suffered an event of abnormal mortality that was significantly associated with OsHV-1 infection. Those animals were infected with a previously undescribed microvariant whereas the other stocks were infected with OsHV-1 μVar. Cell lesions due to the infection were observed by histology and true infections were corroborated by in situ hybridization. Survivors from the natural outbreak were exposed to OsHV-1 μVar by intramuscular injection and were compared to naïve animals. The survival rate in previously exposed animals was significantly higher than in naïve oysters. Results derived from this study allowed the selection of animals that might possess interesting characteristics for future analysis on OsHV-1 resistance.
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Affiliation(s)
- Maria Prado-Alvarez
- Aquaculture and Fisheries Development Centre, School of Biological, Earth and Environmental Science and Environmental Research Institute, University College Cork Cork, Ireland
| | - Grainne Darmody
- Aquaculture and Fisheries Development Centre, School of Biological, Earth and Environmental Science and Environmental Research Institute, University College Cork Cork, Ireland
| | - Stephen Hutton
- Aquaculture and Fisheries Development Centre, School of Biological, Earth and Environmental Science and Environmental Research Institute, University College Cork Cork, Ireland
| | - Amy O'Reilly
- Aquaculture and Fisheries Development Centre, School of Biological, Earth and Environmental Science and Environmental Research Institute, University College Cork Cork, Ireland
| | - Sharon A Lynch
- Aquaculture and Fisheries Development Centre, School of Biological, Earth and Environmental Science and Environmental Research Institute, University College Cork Cork, Ireland
| | - Sarah C Culloty
- Aquaculture and Fisheries Development Centre, School of Biological, Earth and Environmental Science and Environmental Research Institute, University College Cork Cork, Ireland
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28
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Green TJ, Helbig K, Speck P, Raftos DA. Primed for success: Oyster parents treated with poly(I:C) produce offspring with enhanced protection against Ostreid herpesvirus type I infection. Mol Immunol 2016; 78:113-120. [PMID: 27616590 DOI: 10.1016/j.molimm.2016.09.002] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Revised: 08/31/2016] [Accepted: 09/01/2016] [Indexed: 12/17/2022]
Abstract
The Pacific oyster (Crassostrea gigas) is farmed globally. Ostreid herpesvirus (OsHV-1) causes severe mortalities of farmed C. gigas. Management of OsHV-1 has proven difficult. Oysters treated with poly(I:C) exhibit enhanced protection (EP) against OsHV-1. This chemical treatment is highly effective, but it is not feasible to treat every oyster on a farm. To circumvent this practical limitation, previous studies on arthropods have suggested that EP can be transferred from parents to their offspring (trans-generational EP, TGEP). This suggests that the treatment of relatively few parents could be used to produce large numbers of offspring with TGEP. Here, we investigated TGEP in oysters to test whether it might be used as a cost effective management tool to control OsHV-1. We found that offspring (D-veliger larvae) produced from poly(I:C)-treated parents had double the chance of surviving exposure to OsHV-1 compared to controls. Furthermore, the larvae of poly(I:C)-treated parents contained elevated levels of mRNA encoding a key transcription factor that regulates antiviral immunity (IRF2). Poly(I:C) treatment had no effect on the survival of oyster parents. Hence, the enhanced immunity of their offspring could not be explained by genetic selection, and instead may reflect epigenetic reprogramming or maternal provisioning.
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Affiliation(s)
- Timothy J Green
- Macquarie University, Department of Biological Sciences, Sydney, NSW, Australia; Sydney Institute of Marine Science, Chowder Bay, Mosman, NSW, Australia.
| | - Karla Helbig
- La Trobe University, Department of Physiology, Anatomy and Microbiology, School of Life Sciences, Melbourne, Victoria, Australia
| | - Peter Speck
- Flinders University, Department of Biological Sciences, Adelaide, South Australia, Australia
| | - David A Raftos
- Macquarie University, Department of Biological Sciences, Sydney, NSW, Australia; Sydney Institute of Marine Science, Chowder Bay, Mosman, NSW, Australia
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López-Sanmartín M, López-Fernández JR, Cunha ME, De la Herrán R, Navas JI. Ostreid herpesvirus in wild oysters from the Huelva coast (SW Spain). DISEASES OF AQUATIC ORGANISMS 2016; 120:231-240. [PMID: 27503919 DOI: 10.3354/dao03031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
This is the first report of ostreid herpesvirus 1 microvariant (OsHV-1 µVar) infecting natural oyster beds located in Huelva (SW Spain). The virus was detected in 3 oyster species present in the intertidal zone: Crassostrea gigas (Thunberg, 1793), C. angulata (Lamarck, 1819) and, for the first time, in Ostrea stentina Payraudeau, 1826. Oysters were identified by a specific polymerase chain reaction (PCR) and posterior restriction fragment length polymorphism (RFLP) analysis based on cytochrome oxidase I (COI) mitochondrial DNA. Results confirmed that C. angulata still remains the dominant oyster population in SW Spain despite the introduction of C. gigas for cultivation in the late 1970s, and its subsequent naturalization. C. angulata shows a higher haplotype diversity than C. gigas. OsHV-1 virus was detected by PCR with C2/C6 pair primers. Posterior RFLP analyses with the restriction enzyme MfeI were done in order to reveal the OsHV-1 µVar. Detections were confirmed by DNA sequencing, and infections were evidenced by in situ hybridization in C. gigas, C. angulata and O. stentina samples. The prevalence was similar among the 3 oyster species but varied between sampling locations, being higher in areas with greater harvesting activities. OsHV-1 µVar accounted for 93% of all OsHV-1 detected.
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Affiliation(s)
- M López-Sanmartín
- IFAPA Centro Agua del Pino, Consejería de Agricultura, Pesca y Desarrollo Rural, Junta de Andalucía, Ctra. El Rompido-Punta Umbría Km 3.8, 21459 Cartaya, Huelva, Spain
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Azéma P, Travers MA, Benabdelmouna A, Dégremont L. Single or dual experimental infections with Vibrio aestuarianus and OsHV-1 in diploid and triploid Crassostrea gigas at the spat, juvenile and adult stages. J Invertebr Pathol 2016; 139:92-101. [PMID: 27503207 DOI: 10.1016/j.jip.2016.08.002] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Revised: 08/03/2016] [Accepted: 08/04/2016] [Indexed: 11/15/2022]
Abstract
French production of the Pacific cupped oyster, Crassostrea gigas, is currently threatened by two pathogens, OsHV-1 and V. aestuarianus. While oysters selected for their higher resistance to OsHV-1 are now available for the industry, the impact of V. aestuarianus on such oysters is unknown, especially for triploids. In addition, experimental infection has used the virus or the bacteria alone, but there have been no investigations of dual exposure to these pathogens. This study is the first report of single or dual exposure in spat (Spat1 and Spat2), juvenile and adult naïve oysters. For each of the two stocks evaluated, unselected oysters and oysters selected for their higher resistance to OsHV-1 infection were tested, as well as their triploid siblings of the selected oysters produced using cytochalasin B. We confirmed that resistance to OsHV-1 infection and susceptibility to V. aestuarianus increased with age and size, although selected oysters were not significantly impacted by OsHV-1 whatever their ploidy, size or age. We found different mortality patterns depending on the pathogen tested. The mortality pattern was similar for oysters exposed to OsHV-1 or to both pathogens in the Spat1 trial (4months old and 1.9g). The mortality pattern was similar for oysters exposed to V. aestuarianus or to both pathogens in the Adult trial (25months old and 63.1g). Surprisingly, mortality was much higher (ranging from 75.9% to 100%), in particular for the selected oysters, for the Spat2 (8months old/3.9g) and Juvenile trials (16months old/18.4g) given a dual exposure, regardless of the level of selection for OsHV-1 and the ploidy state. Our findings highlight an important threat for oyster farmers: oysters exposed to both pathogens could experience dramatic mortality rates, even in oysters selected for their higher resistance to OsHV-1. Finally, our study demonstrated for the first time that triploid oysters were more susceptible to experimental challenges with V. aestuarianus at the spat stage than their diploid siblings. However, the difference in mortality between the triploids and diploids remained limited and ranged from 22.9% to 6.6% for spat and adults, respectively with a relatively regularly decrease in the difference with increased age.
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Affiliation(s)
- Patrick Azéma
- Ifremer, RBE-SG2M-LGPMM, station de la Tremblade, F-17390, France.
| | | | | | - Lionel Dégremont
- Ifremer, RBE-SG2M-LGPMM, station de la Tremblade, F-17390, France.
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31
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Corbeil S, Williams LM, McColl KA, Crane MSJ. Australian abalone (Haliotis laevigata, H. rubra and H. conicopora) are susceptible to infection by multiple abalone herpesvirus genotypes. DISEASES OF AQUATIC ORGANISMS 2016; 119:101-106. [PMID: 27137068 DOI: 10.3354/dao02989] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
From 2006 to 2012, acute mortalities occurred in farmed and wild abalone (Haliotis spp.) along the coast of Victoria, Australia. The disease (abalone viral ganglioneuritis; AVG) is associated with infection by an abalone herpesvirus (AbHV). The relative pathogenicity of 5 known variants of AbHV was evaluated on abalone stocks from different states in Australia. Results indicated that all virus variants (Vic1, Tas1, Tas2, Tas3 and Tas4) cause disease and mortality in all abalone stocks tested (greenlip, blacklip and brownlip). In order to avoid further AVG outbreaks in Australian wild abalone, strict regulations on the transfer of abalone stocks must be implemented.
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Affiliation(s)
- Serge Corbeil
- CSIRO Health and Biosecurity, Australian Animal Health Laboratory, 5 Portarlington Road, Geelong East, Victoria 3220, Australia
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32
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López Sanmartín M, Power DM, de la Herrán R, Navas JI, Batista FM. Experimental infection of European flat oyster Ostrea edulis with ostreid herpesvirus 1 microvar (OsHV-1μvar): Mortality, viral load and detection of viral transcripts by in situ hybridization. Virus Res 2016; 217:55-62. [PMID: 26945849 DOI: 10.1016/j.virusres.2016.01.023] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Accepted: 01/29/2016] [Indexed: 11/29/2022]
Abstract
Ostreid herpesvirus 1 (OsHV-1) infections have been reported in several bivalve species. Mortality of Pacific oyster Crassostrea gigas spat has increased considerably in Europe since 2008 linked to the spread of a variant of OsHV-1 called μvar. In the present study we demonstrated that O. edulis juveniles can be infected by OsHV-1μvar when administered as an intramuscular injection. Mortality in the oysters injected with OsHV-1μvar was first detected 4 days after injection and reached 25% mortality at day 10. Moreover, the high viral load observed and the detection of viral transcripts by in situ hybridization in several tissues of dying oysters suggested that OsHV-1μvar was the cause of mortality in the O. edulis juveniles. This is therefore the first study to provide evidence about the pathogenicity of OsHV-1μvar in a species that does not belong to the Crassostrea genus. Additionally, we present a novel method to detect OsHV-1 transcripts in infected individuals' using in situ hybridization.
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Affiliation(s)
- Monserrat López Sanmartín
- Instituto de Investigación y Formación Agraria y Pesquera (IFAPA), Centro Agua del Pino, Junta de Andalucía, Ctra. El Rompido-Punta Umbría, km 4, 21459 Cartaya, Spain.
| | - Deborah M Power
- Centro de Ciências do Mar (CCMAR), Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal
| | | | - José I Navas
- Instituto de Investigación y Formación Agraria y Pesquera (IFAPA), Centro Agua del Pino, Junta de Andalucía, Ctra. El Rompido-Punta Umbría, km 4, 21459 Cartaya, Spain
| | - Frederico M Batista
- Centro de Ciências do Mar (CCMAR), Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal; Instituto Português do Mar e da Atmosfera, Divisão de Aquicultura e Valorização, Estação Experimental de Moluscicultura de Tavira, Av. 5 de Outubro, 8700-305 Olhão, Portugal
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Azéma P, Travers MA, De Lorgeril J, Tourbiez D, Dégremont L. Can selection for resistance to OsHV-1 infection modify susceptibility to Vibrio aestuarianus infection in Crassostrea gigas? First insights from experimental challenges using primary and successive exposures. Vet Res 2015; 46:139. [PMID: 26646058 PMCID: PMC4673786 DOI: 10.1186/s13567-015-0282-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Accepted: 11/13/2015] [Indexed: 12/17/2022] Open
Abstract
Since 2008, the emergent virus OsHV-1µvar has provoked massive mortality events in Crassostrea gigas spat and juveniles in France. Since 2012, mortality driven by the pathogenic bacteria Vibrio aestuarianus has stricken market-sized adults. A hypothesis to explain the sudden increase in mortality observed in France since 2012 is that selective pressure due to recurrent viral infections could have led to a higher susceptibility of adults to Vibrio infection. In our study, two OsHV-1-resistant lines (AS and BS) and their respective controls (AC and BC) were experimentally challenged in the laboratory to determine their level of susceptibility to V. aestuarianus infection. At the juvenile stage, the selected lines exhibited lower mortality (14 and 33%) than the control lines (71 and 80%), suggesting dual-resistance to OsHV-1 and V. aestuarianus in C. gigas. Interestingly, this pattern was not observed at the adult stage, where higher mortality was detected for AS (68%) and BC (62%) than AC (39%) and BS (49%). These results were confirmed by the analysis of the expression of 31 immune-related genes in unchallenged oysters. Differential gene expression discriminated oysters according to their susceptibility to infection at both the juvenile and adult stages, suggesting that resistance to V. aestuarianus infection resulted in complex interactions between the genotype, stage of development and immunity status. Finally, survivors of the V. aestuarianus challenge at the juvenile stage still exhibited significant mortality at the adult stage during a second and third V. aestuarianus challenge, indicating that these survivors were not genetically resistant.
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Affiliation(s)
- Patrick Azéma
- Ifremer, Laboratoire de Génétique et Pathologie des Mollusques Marins, Avenue Mus de Loup, 17390, La Tremblade, France.
| | - Marie-Agnès Travers
- Ifremer, Laboratoire de Génétique et Pathologie des Mollusques Marins, Avenue Mus de Loup, 17390, La Tremblade, France.
| | - Julien De Lorgeril
- Ifremer, IHPE, UMR 5244, Univ. Perpignan Via Domitia, CNRS, Univ. Montpellier, 34095, Montpellier, France.
| | - Delphine Tourbiez
- Ifremer, Laboratoire de Génétique et Pathologie des Mollusques Marins, Avenue Mus de Loup, 17390, La Tremblade, France.
| | - Lionel Dégremont
- Ifremer, Laboratoire de Génétique et Pathologie des Mollusques Marins, Avenue Mus de Loup, 17390, La Tremblade, France.
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34
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Dégremont L, Garcia C, Allen SK. Genetic improvement for disease resistance in oysters: A review. J Invertebr Pathol 2015; 131:226-41. [PMID: 26037230 DOI: 10.1016/j.jip.2015.05.010] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Revised: 05/12/2015] [Accepted: 05/13/2015] [Indexed: 10/23/2022]
Abstract
Oyster species suffer from numerous disease outbreaks, often causing high mortality. Because the environment cannot be controlled, genetic improvement for disease resistance to pathogens is an attractive option to reduce their impact on oyster production. We review the literature on selective breeding programs for disease resistance in oyster species, and the impact of triploidy on such resistance. Significant response to selection to improve disease resistance was observed in all studies after two to four generations of selection for Haplosporidium nelsoni and Roseovarius crassostrea in Crassostrea virginica, OsHV-1 in Crassostrea gigas, and Martelia sydneyi in Saccostrea glomerata. Clearly, resistance in these cases was heritable, but most of the studies failed to provide estimates for heritability or genetic correlations with other traits, e.g., between resistance to one disease and another. Generally, it seems breeding for higher resistance to one disease does not confer higher resistance or susceptibility to another disease. For disease resistance in triploid oysters, several studies showed that triploidy confers neither advantage nor disadvantage in survival, e.g., OsHV-1 resistance in C. gigas. Other studies showed higher disease resistance of triploids over diploid as observed in C. virginica and S. glomerata. One indirect mechanism for triploids to avoid disease was to grow faster, thus limiting the span of time when oysters might be exposed to disease.
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Affiliation(s)
- Lionel Dégremont
- SG2M, LGPMM, Ifremer, Avenue Mus de Loup, 17390 La Tremblade, France.
| | - Céline Garcia
- SG2M, LGPMM, Ifremer, Avenue Mus de Loup, 17390 La Tremblade, France.
| | - Standish K Allen
- Aquaculture Genetics and Breeding Technology Center, Virginia Institute of Marine Science, College of William and Mary, 1208 Greate Road, Gloucester Point, VA 23062-1346, USA.
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