1
|
Zhang X, Huang BW, Zheng YD, Xin LS, Chen WB, Yu T, Li C, Wang CM, Bai CM. Identification and Characterization of Infectious Pathogens Associated with Mass Mortalities of Pacific Oyster ( Crassostrea gigas) Cultured in Northern China. BIOLOGY 2023; 12:759. [PMID: 37372044 DOI: 10.3390/biology12060759] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 05/10/2023] [Accepted: 05/19/2023] [Indexed: 06/29/2023]
Abstract
The Pacific oyster (Crassostrea gigas) aquaculture industry increased rapidly in China with the introduction and promotion of triploid oysters in recent years. Mass mortalities affecting different life stages of Pacific oysters emerged periodically in several important production areas of Northern China. During 2020 and 2021, we conducted a passive two-year investigation of infectious pathogens linked to mass mortality. Ostreid herpesvirus-1 (OsHV-1) was detected to be associated with mass mortalities of hatchery larvae, but not juveniles and adults in the open sea. Protozoan parasites, such as Marteilia spp., Perkinsus spp. and Bonamia spp. were not detected. Bacterial isolation and identification revealed that Vibrio natriegens and Vibrio alginolyticus were the most frequently (9 out of 13) identified two dominant bacteria associated with mass mortalities. Pseudoalteromonas spp. was identified as the dominant bacteria in three mortality events that occurred during the cold season. Further bacteriological analysis was conducted on two representative isolates of V. natriegens and V. alginolyticus, designated as CgA1-1 and CgA1-2. Multisequence analysis (MLSA) showed that CgA1-1 and CgA1-2 were closely related to each other and nested within the Harveyi clade. Bacteriological investigation revealed faster growth, and more remarkable haemolytic activity and siderophore production capacity at 25 °C than at 15 °C for both CgA1-1 and CgA1-2. The accumulative mortalities of experimental immersion infections were also higher at 25 °C (90% and 63.33%) than at 15 °C (43.33% and 33.33%) using both CgA1-1 and CgA1-2, respectively. Similar clinical and pathological features were identified in samples collected during both naturally and experimentally occurring mortalities, such as thin visceral mass, discolouration, and connective tissue and digestive tube lesions. The results presented here highlight the potential risk of OsHV-1 to hatchery production of larvae, and the pathogenic role of V. natriegens and V. alginolyticus during mass mortalities of all life stages of Pacific oysters in Northern China.
Collapse
Affiliation(s)
- Xiang Zhang
- Key Laboratory of Maricultural Organism Disease Control, Ministry of Agriculture, Qingdao Key Laboratory of Mariculture Epidemiology and Biosecurity, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao 266071, China
| | - Bo-Wen Huang
- Key Laboratory of Maricultural Organism Disease Control, Ministry of Agriculture, Qingdao Key Laboratory of Mariculture Epidemiology and Biosecurity, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao 266071, China
| | - Yu-Dong Zheng
- Key Laboratory of Maricultural Organism Disease Control, Ministry of Agriculture, Qingdao Key Laboratory of Mariculture Epidemiology and Biosecurity, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao 266071, China
| | - Lu-Sheng Xin
- Key Laboratory of Maricultural Organism Disease Control, Ministry of Agriculture, Qingdao Key Laboratory of Mariculture Epidemiology and Biosecurity, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao 266071, China
- Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China
| | - Wen-Bo Chen
- Dalian Modern Agricultural Production Development Service Center, Dalian 116023, China
| | - Tao Yu
- Changdao Enhancement and Experiment Station, Chinese Academy of Fishery Sciences, Yantai 265800, China
| | - Chen Li
- Key Laboratory of Maricultural Organism Disease Control, Ministry of Agriculture, Qingdao Key Laboratory of Mariculture Epidemiology and Biosecurity, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao 266071, China
- Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China
| | - Chong-Ming Wang
- Key Laboratory of Maricultural Organism Disease Control, Ministry of Agriculture, Qingdao Key Laboratory of Mariculture Epidemiology and Biosecurity, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao 266071, China
- Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China
| | - Chang-Ming Bai
- Key Laboratory of Maricultural Organism Disease Control, Ministry of Agriculture, Qingdao Key Laboratory of Mariculture Epidemiology and Biosecurity, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao 266071, China
- Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China
| |
Collapse
|
2
|
Trancart S, Tweedie A, Liu O, Paul-Pont I, Hick P, Houssin M, Whittington RJ. Diversity and molecular epidemiology of Ostreid herpesvirus 1 in farmed Crassostrea gigas in Australia: Geographic clusters and implications for "microvariants" in global mortality events. Virus Res 2023; 323:198994. [PMID: 36332723 PMCID: PMC10194400 DOI: 10.1016/j.virusres.2022.198994] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2022] [Revised: 10/26/2022] [Accepted: 10/31/2022] [Indexed: 11/08/2022]
Abstract
Since 2010, mass mortality events known as Pacific oyster mortality syndrome (POMS) have occurred in Crassostrea gigas in Australia associated with Ostreid herpesvirus 1. The virus was thought to be an OsHV-1 µVar or "microvariant", i.e. one of the dominant variants associated with POMS in Europe, but there are few data to characterize the genotype in Australia. Consequently, the genetic identity and diversity of the virus was determined to understand the epidemiology of the disease in Australia. Samples were analysed from diseased C. gigas over five summer seasons between 2011 and 2016 in POMS-affected estuaries: Georges River in New South Wales (NSW), Hawkesbury River (NSW) and Pitt Water in Tasmania. Sequencing was attempted for six genomic regions. Numerous variants were identified among these regions (n = 100 isolates) while twelve variants were identified from concatenated nucleotide sequences (n = 61 isolates). Nucleotide diversity of the seven genotypes of C region among Australian isolates (Pi 0.99 × 10-3) was the lowest globally. All Australian isolates grouped in a cluster distinct from other OsHV-1 isolates worldwide. This is the first report that Australian outbreaks of POMS were associated with OsHV-1 distinct from OsHV-1 reference genotype, µVar and other microvariants from other countries. The findings illustrate that microvariants are not the only variants of OsHV-1 associated with mass mortality events in C. gigas. In addition, there was mutually exclusive spatial clustering of viral genomic and amino acid sequence variants between estuaries, and a possible association between genotype/amino acid sequence and the prevalence and severity of POMS, as this differed between these estuaries. The sequencing findings supported prior epidemiological evidence for environmental reservoirs of OsHV-1 for POMS outbreaks in Australia.
Collapse
Affiliation(s)
- Suzanne Trancart
- LABÉO Research Department, 1 Route de Rosel, Cedex 4, Caen 14053, France
| | - Alison Tweedie
- The University of Sydney, Sydney School of Veterinary Science, Faculty of Science, 425 Werombi Rd, Camden, NSW 2570, Australia; Department of Primary Industries, Elizabeth Macarthur Agricultural Institute, Menangle, NSW 2568, Australia
| | - Olivia Liu
- The University of Sydney, Sydney School of Veterinary Science, Faculty of Science, 425 Werombi Rd, Camden, NSW 2570, Australia; Department of Agriculture, Water and the Environment, Canberra, ACT 2601, Australia
| | - Ika Paul-Pont
- The University of Sydney, Sydney School of Veterinary Science, Faculty of Science, 425 Werombi Rd, Camden, NSW 2570, Australia; LEMAR, Rue Dumont d'Urville, Plouzané 29280, France
| | - Paul Hick
- The University of Sydney, Sydney School of Veterinary Science, Faculty of Science, 425 Werombi Rd, Camden, NSW 2570, Australia; Department of Primary Industries, Elizabeth Macarthur Agricultural Institute, Menangle, NSW 2568, Australia
| | - Maryline Houssin
- LABÉO Research Department, 1 Route de Rosel, Cedex 4, Caen 14053, France; UMR BOREA Université de Caen Normandie, MNHN, CNRS 8067, SU, IRD 207, UCN, UA, Esplanade de la Paix Caen Cedex 4 14032, France
| | - Richard J Whittington
- The University of Sydney, Sydney School of Veterinary Science, Faculty of Science, 425 Werombi Rd, Camden, NSW 2570, Australia.
| |
Collapse
|
3
|
Dotto-Maurel A, Pelletier C, Morga B, Jacquot M, Faury N, Dégremont L, Bereszczynki M, Delmotte J, Escoubas JM, Chevignon G. Evaluation of tangential flow filtration coupled to long-read sequencing for ostreid herpesvirus type 1 genome assembly. Microb Genom 2022; 8:mgen000895. [PMID: 36355418 PMCID: PMC9836095 DOI: 10.1099/mgen.0.000895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Whole-genome sequencing is widely used to better understand the transmission dynamics, the evolution and the emergence of new variants of viral pathogens. This can bring crucial information to stakeholders for disease management. Unfortunately, aquatic virus genomes are usually difficult to characterize because most of these viruses cannot be easily propagated in vitro. Developing methodologies for routine genome sequencing of aquatic viruses is timely given the ongoing threat of disease emergence. This is particularly true for pathogenic viruses infecting species of commercial interest that are widely exchanged between production basins or countries. For example, the ostreid herpesvirus type 1 (OsHV-1) is a Herpesvirus widely associated with mass mortality events of juvenile Pacific oyster Crassostrea gigas. Genomes of Herpesviruses are large and complex with long direct and inverted terminal repeats. In addition, OsHV-1 is unculturable. It therefore accumulates several features that make its genome sequencing and assembly challenging. To overcome these difficulties, we developed a tangential flow filtration (TFF) method to enrich OsHV-1 infective particles from infected host tissues. This virus purification allowed us to extract high molecular weight and high-quality viral DNA that was subjected to Illumina short-read and Nanopore long-read sequencing. Dedicated bioinformatic pipelines were developed to assemble complete OsHV-1 genomes with reads from both sequencing technologies. Nanopore sequencing allowed characterization of new structural variations and major viral isomers while having 99,98 % of nucleotide identity with the Illumina assembled genome. Our study shows that TFF-based purification method, coupled with Nanopore sequencing, is a promising approach to enable in field sequencing of unculturable aquatic DNA virus.
Collapse
Affiliation(s)
| | | | | | | | | | | | | | - Jean Delmotte
- IHPE, Univ. Montpellier, CNRS, Ifremer, UPVD, F-34095 Montpellier, France
| | - Jean-Michel Escoubas
- IHPE, Univ. Montpellier, CNRS, Ifremer, UPVD, F-34095 Montpellier, France,*Correspondence: Jean-Michel Escoubas,
| | - Germain Chevignon
- Ifremer, ASIM, F-17390 La Tremblade, France,*Correspondence: Germain Chevignon,
| |
Collapse
|
4
|
Morga B, Jacquot M, Pelletier C, Chevignon G, Dégremont L, Biétry A, Pepin JF, Heurtebise S, Escoubas JM, Bean TP, Rosani U, Bai CM, Renault T, Lamy JB. Genomic Diversity of the Ostreid Herpesvirus Type 1 Across Time and Location and Among Host Species. Front Microbiol 2021; 12:711377. [PMID: 34326830 PMCID: PMC8313985 DOI: 10.3389/fmicb.2021.711377] [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: 05/18/2021] [Accepted: 06/21/2021] [Indexed: 11/15/2022] Open
Abstract
The mechanisms underlying virus emergence are rarely well understood, making the appearance of outbreaks largely unpredictable. This is particularly true for pathogens with low per-site mutation rates, such as DNA viruses, that do not exhibit a large amount of evolutionary change among genetic sequences sampled at different time points. However, whole-genome sequencing can reveal the accumulation of novel genetic variation between samples, promising to render most, if not all, microbial pathogens measurably evolving and suitable for analytical techniques derived from population genetic theory. Here, we aim to assess the measurability of evolution on epidemiological time scales of the Ostreid herpesvirus 1 (OsHV-1), a double stranded DNA virus of which a new variant, OsHV-1 μVar, emerged in France in 2008, spreading across Europe and causing dramatic economic and ecological damage. We performed phylogenetic analyses of heterochronous (n = 21) OsHV-1 genomes sampled worldwide. Results show sufficient temporal signal in the viral sequences to proceed with phylogenetic molecular clock analyses and they indicate that the genetic diversity seen in these OsHV-1 isolates has arisen within the past three decades. OsHV-1 samples from France and New Zealand did not cluster together suggesting a spatial structuration of the viral populations. The genome-wide study of simple and complex polymorphisms shows that specific genomic regions are deleted in several isolates or accumulate a high number of substitutions. These contrasting and non-random patterns of polymorphism suggest that some genomic regions are affected by strong selective pressures. Interestingly, we also found variant genotypes within all infected individuals. Altogether, these results provide baseline evidence that whole genome sequencing could be used to study population dynamic processes of OsHV-1, and more broadly herpesviruses.
Collapse
Affiliation(s)
| | | | | | | | | | | | - Jean-François Pepin
- Ifremer, ODE-Littoral-Laboratoire Environnement Ressources des Pertuis Charentais (LER-PC), La Tremblade, France
| | | | - Jean-Michel Escoubas
- IHPE, CNRS, Ifremer, Université de Montpellier - Université de Perpignan Via Domitia, Montpellier, France
| | - Tim P Bean
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Midlothian, United Kingdom.,Centre for Environment, Fisheries and Aquaculture Science, Weymouth, United Kingdom
| | - Umberto Rosani
- Department of Biology, University of Padua, Padua, Italy
| | - Chang-Ming Bai
- Yellow Sea Fisheries Research Institute, CAFS, Qingdao, China
| | | | | |
Collapse
|
5
|
Prado-Alvarez M, García-Fernández P, Faury N, Azevedo C, Morga B, Gestal C. First detection of OsHV-1 in the cephalopod Octopus vulgaris. Is the octopus a dead-end for OsHV-1? J Invertebr Pathol 2021; 183:107553. [PMID: 33596434 DOI: 10.1016/j.jip.2021.107553] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Revised: 01/28/2021] [Accepted: 02/09/2021] [Indexed: 11/29/2022]
Abstract
The ostreid herpes virus (OsHV-1), associated with massive mortalities in the bivalve Crassostrea gigas, was detected for the first time in the cephalopod Octopus vulgaris. Wild adult animals from a natural breeding area in Spain showed an overall prevalence of detection of 87.5% between 2010 and 2015 suggesting an environmental source of viral material uptake. Overall positive PCR detections were significantly higher in adult animals (p = 0.031) compared to newly hatched paralarvae (62%). Prevalence in embryos reached 65%. Sequencing of positive amplicons revealed a match with the variant OsHV-1 µVar showing the genomic features that distinguish this variant in the ORF4. Gill tissues from adult animals were also processed for in situ hybridization and revealed positive labelling. Experimental exposure trials in octopus paralarvae were carried out by cohabitation with virus injected oysters and by immersion in viral suspension observing a significant decrease in paralarval survival in both experiments. An increase in the number of OsHV-1 positive animals was detected in dead paralarvae after cohabitation with virus injected oysters. No signs of viral replication were observed based on lack of viral gene expression or visualization of viral structures by transmission electron microscopy. The octopus response against OsHV-1 was evaluated by gene expression of previously reported transcripts involved in immune response in C. gigas suggesting that immune defences in octopus are also activated after exposure to OsHV-1.
Collapse
Affiliation(s)
- Maria Prado-Alvarez
- Marine Molecular Pathobiology Group, Marine Research Institute, Spanish National Research Council, Eduardo Cabello 6, 36208 Vigo, Spain.
| | - Pablo García-Fernández
- Marine Molecular Pathobiology Group, Marine Research Institute, Spanish National Research Council, Eduardo Cabello 6, 36208 Vigo, Spain
| | - Nicole Faury
- IFREMER, Laboratoire de Génétique et Pathologie des Mollusques Marins, Avenue de Mus de Loup, 17390 La Tremblade, France
| | - Carlos Azevedo
- Interdisciplinary Center of Marine and Environmental Research, University of Porto, Rua dos Bragas 289, 4050-123 Porto, Portugal; Institute of Biomedical Sciences Abel Salazar, University of Porto, Rua Jorge Viterbo Ferreira 228, 4050-313 Porto, Portugal
| | - Benjamin Morga
- IFREMER, Laboratoire de Génétique et Pathologie des Mollusques Marins, Avenue de Mus de Loup, 17390 La Tremblade, France
| | - Camino Gestal
- Marine Molecular Pathobiology Group, Marine Research Institute, Spanish National Research Council, Eduardo Cabello 6, 36208 Vigo, Spain.
| |
Collapse
|
6
|
Mendes AF, Goncalves P, Serrano-Solis V, Silva PMD. Identification of candidate microRNAs from Ostreid herpesvirus-1 (OsHV-1) and their potential role in the infection of Pacific oysters (Crassostrea gigas). Mol Immunol 2020; 126:153-164. [PMID: 32853878 DOI: 10.1016/j.molimm.2020.08.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 07/31/2020] [Accepted: 08/06/2020] [Indexed: 12/21/2022]
Abstract
Oyster production is an economic activity of great interest worldwide. Recently, oysters have been suffering significant mortalities from OsHV-1infection, which has resulted in substantial economic loses in several countries around the world. Understanding viral pathogenicity mechanisms is of central importance for the establishment of disease control measures. Thus, the present work aimed to identify and characterize miRNAs from OsHV-1 as well as to predict their target transcripts in the virus and the host. OsHV-1 genome was used for the in silico discovery of pre-miRNAs. Subsequently, viral and host target transcripts of the OsHV-1 miRNAs were predicted according to the base pairing interaction between mature miRNAs and mRNA 3' untranslated regions (UTRs). Six unique pre-miRNAs were found in different regions of the viral genome, ranging in length from 85 to 172 nucleotides. A complex network of self-regulation of viral gene expression mediated by the miRNAs was identified. These sequences also seem to have a broad ability to regulate the expression of host immune-related genes, especially those associated with pathogen recognition. Our results suggest that OsHV-1 encodes miRNAs with important functions in the infection process, inducing self-regulation of viral transcripts, as well as affecting the regulation of Pacific oyster transcripts related to immunity. Understanding the molecular basis of host-pathogen interactions can help mitigate the recurrent events of oyster mass mortalities by OsHV-1 observed worldwide.
Collapse
Affiliation(s)
- Andrei Félix Mendes
- Laboratório de Imunologia e Patologia de Invertebrados (LABIPI), Departamento de Biologia Molecular, Universidade Federal da Paraíba (UFPB), 58051-900, João Pessoa, Paraíba, Brazil
| | - Priscila Goncalves
- Environment and Sustainability Institute, University of Exeter, Penryn, Cornwall, TR10 9FE, UK
| | - Victor Serrano-Solis
- Laboratório de Imunologia e Patologia de Invertebrados (LABIPI), Departamento de Biologia Molecular, Universidade Federal da Paraíba (UFPB), 58051-900, João Pessoa, Paraíba, Brazil
| | - Patricia Mirella da Silva
- Laboratório de Imunologia e Patologia de Invertebrados (LABIPI), Departamento de Biologia Molecular, Universidade Federal da Paraíba (UFPB), 58051-900, João Pessoa, Paraíba, Brazil.
| |
Collapse
|
7
|
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.
Collapse
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
| |
Collapse
|
8
|
Xin L, Huang B, Zhang H, Li C, Bai C, Wang C. OsHV-1 infection leads to mollusc tissue lesion and iron redistribution, revealing a strategy of iron limitation against pathogen. Metallomics 2020; 11:822-832. [PMID: 30843573 DOI: 10.1039/c9mt00018f] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The mass mortality of molluscs caused by OsHV-1 infection has frequently occurred worldwide in recent years. Meanwhile the interaction between OsHV-1 and its host is largely unknown. Innate immunity mainly makes up the mollusc defense system, due to the lack of adaptive immunity in invertebrates. The iron limitation strategy is an indispensable facet of innate immunity across vertebrate and invertebrate species. In this study, an iron limitation strategy was interestingly found to contribute to mollusc innate immune responses against OsHV-1 infection. Firstly, ark clams, Scapharca broughtonii, were experimentally infected with OsHV-1, and serious hyperaemia in hepatopancreases and the erosion of gills were observed post OsHV-1 infection according to a histology assay. Meanwhile, based on quantification and Prussian blue staining, the process of iron efflux from ark clams was described post OsHV-1 infection. Secondly, ferritin, as an important iron storage protein, was characterized in ark clams and showed significant iron binding activity. According to the results of an immunohistochemistry assay, ferritin was supposed to be responsible for the iron translocation in ark clams post OsHV-1 infection. Its expression level was significantly fluctuant in response to OsHV-1 infection. Finally, oxidative stress was assessed by the analyses of H2O2 content, total antioxidant capacity and MDA level post OsHV-1 infection. Supplementary iron was found to promote ROS generation and death of hemocytes in vivo. These results highlighted that microenvironment changes in the essential nutrient iron should be an important aspect of the pathogenesis of OsHV-1 disease.
Collapse
Affiliation(s)
- Lusheng Xin
- Qingdao Key Laboratory of Mariculture Epidemiology and Biosecurity, Key Laboratory of Maricultural Organism Disease Control, Ministry of Agriculture, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Function Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071, P. R. China.
| | | | | | | | | | | |
Collapse
|
9
|
Martínez-García MF, Grijalva-Chon JM, Castro-Longoria R, Re-Vega ED, Varela-Romero A, Chávez-Villalba JE. Prevalence and genotypic diversity of ostreid herpesvirus type 1 in Crassostrea gigas cultured in the Gulf of California, Mexico. DISEASES OF AQUATIC ORGANISMS 2020; 138:185-194. [PMID: 32213666 DOI: 10.3354/dao03462] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
In bivalve mollusk aquaculture, massive disease outbreaks with high mortality and large economic losses can occur, as in northwest Mexico in the 1990s. A range of pathogens can affect bivalves; one of great concern is ostreid herpesvirus 1 (OsHV-1), of which there are several strains. This virus has been detected in the Gulf of California in occasional or sporadic samplings, but to date, there have been few systematic studies. Monthly samples of Crassostrea gigas, water, and sediment were taken in the La Cruz coastal lagoon and analyzed by PCR. The native mollusk, Dosinia ponderosa, which lives outside the lagoon, was sampled as a control. The virus was found throughout the year only in C. gigas, with prevalence up to 60%. In total, 9 genotype variants were detected, and genetic analysis suggests that linear genotypic evolution has occurred from strain JF894308, present in La Cruz in 2011. There has been no evidence of the entry of new viral genotypes in the recent past, thus confinement of the virus within the lagoons of the Gulf of California could promote a native genotypic diversity in the short term.
Collapse
|
10
|
Xin L, Wei Z, Bai C, Chen H, Huang B, Wang C. Influence of temperature on the pathogenicity of Ostreid herpesvirus-1 in ark clam, Scapharca broughtonii. J Invertebr Pathol 2019; 169:107299. [PMID: 31786248 DOI: 10.1016/j.jip.2019.107299] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Revised: 11/22/2019] [Accepted: 11/26/2019] [Indexed: 11/27/2022]
Abstract
OsHV-1 is an epidemic pathogen of molluscs, and temperature has been recognized as a decisive environmental factor in its pathogenicity. In recent years, ark clam, Scapharca broughtonii, emerged as a host for OsHV-1. In the north of China, massive summer mortalities of ark clams infected with OsHV-1 have been continuously reported since 2012. However, the interaction between temperature and the pathogenicity of OsHV-1 was unknown in ark clams. In this study, the effect of temperature (10 °C to 18 °C stepped by 2 °C) on the occurrence of OsHV-1 disease in ark clams was analyzed. OsHV-1 infection led to gill erosion but not below the critical low temperature (between 12 °C and 14 °C). However, OsHV-1 persisted for more than 2 weeks at 12 °C post inoculation and replication was reactivated when the temperature was elevated to 18 °C. No significant reduction of OsHV-1 DNA load was found when the temperature descended to 12 °C from 18 °C, while the gill erosion remained unchanged. Ark clams failed to show the capability of effective clearance of OsHV-1 below the critical low temperature. Our results demonstrated that the pathogenicity of OsHV-1 was influenced significantly by temperature. Moreover, high temperature favored infection, which could provide more information to understand summer mortality of ark clams.
Collapse
Affiliation(s)
- Lusheng Xin
- Qingdao Key Laboratory of Mariculture Epidemiology and Biosecurity, Key Laboratory of Maricultural Organism Disease Control, Ministry of Agriculture, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao 266071, China; Function Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071, China
| | - Zhixin Wei
- Qingdao Key Laboratory of Mariculture Epidemiology and Biosecurity, Key Laboratory of Maricultural Organism Disease Control, Ministry of Agriculture, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao 266071, China; Function Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071, China
| | - Changming Bai
- Qingdao Key Laboratory of Mariculture Epidemiology and Biosecurity, Key Laboratory of Maricultural Organism Disease Control, Ministry of Agriculture, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao 266071, China; Function Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071, China
| | - Hao Chen
- Center of Deep Sea Research, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao 266071, China
| | - Bowen Huang
- Qingdao Key Laboratory of Mariculture Epidemiology and Biosecurity, Key Laboratory of Maricultural Organism Disease Control, Ministry of Agriculture, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao 266071, China; Function Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071, China
| | - Chongming Wang
- Qingdao Key Laboratory of Mariculture Epidemiology and Biosecurity, Key Laboratory of Maricultural Organism Disease Control, Ministry of Agriculture, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao 266071, China; Function Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071, China.
| |
Collapse
|
11
|
Rosani U, Bai CM, Maso L, Shapiro M, Abbadi M, Domeneghetti S, Wang CM, Cendron L, MacCarthy T, Venier P. A-to-I editing of Malacoherpesviridae RNAs supports the antiviral role of ADAR1 in mollusks. BMC Evol Biol 2019; 19:149. [PMID: 31337330 PMCID: PMC6651903 DOI: 10.1186/s12862-019-1472-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Accepted: 07/04/2019] [Indexed: 02/06/2023] Open
Abstract
Background Adenosine deaminase enzymes of the ADAR family are conserved in metazoans. They convert adenine into inosine in dsRNAs and thus alter both structural properties and the coding potential of their substrates. Acting on exogenous dsRNAs, ADAR1 exerts a pro- or anti-viral role in vertebrates and Drosophila. Results We traced 4 ADAR homologs in 14 lophotrochozoan genomes and we classified them into ADAD, ADAR1 or ADAR2, based on phylogenetic and structural analyses of the enzymatic domain. Using RNA-seq and quantitative real time PCR we demonstrated the upregulation of one ADAR1 homolog in the bivalve Crassostrea gigas and in the gastropod Haliotis diversicolor supertexta during Ostreid herpesvirus-1 or Haliotid herpesvirus-1 infection. Accordingly, we demonstrated an extensive ADAR-mediated editing of viral RNAs. Single nucleotide variation (SNV) profiles obtained by pairing RNA- and DNA-seq data from the viral infected individuals resulted to be mostly compatible with ADAR-mediated A-to-I editing (up to 97%). SNVs occurred at low frequency in genomic hotspots, denoted by the overlapping of viral genes encoded on opposite DNA strands. The SNV sites and their upstream neighbor nucleotide indicated the targeting of selected adenosines. The analysis of viral sequences suggested that, under the pressure of the ADAR editing, the two Malacoherpesviridae genomes have evolved to reduce the number of deamination targets. Conclusions We report, for the first time, evidence of an extensive editing of Malacoherpesviridae RNAs attributable to host ADAR1 enzymes. The analysis of base neighbor preferences, structural features and expression profiles of molluscan ADAR1 supports the conservation of the enzyme function among metazoans and further suggested that ADAR1 exerts an antiviral role in mollusks. Electronic supplementary material The online version of this article (10.1186/s12862-019-1472-6) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Umberto Rosani
- Department of Biology, University of Padova, 32121, Padova, Italy. .,Helmholtz Centre for Polar and Marine Research, Alfred Wegener Institute (AWI), Wadden Sea Station, 25992, List auf Sylt, Germany.
| | - Chang-Ming Bai
- Chinese Academy of Fishery Sciences, Yellow Sea Fisheries Research Institute, Qingdao, China
| | - Lorenzo Maso
- Department of Biology, University of Padova, 32121, Padova, Italy
| | - Maxwell Shapiro
- Department of Applied Mathematics and Statistics, Stony Brook University, Stony Brook, NY, USA
| | - Miriam Abbadi
- Istituto Zooprofilattico Sperimentale delle Venezie, 35020, Legnaro, Italy
| | | | - Chong-Ming Wang
- Chinese Academy of Fishery Sciences, Yellow Sea Fisheries Research Institute, Qingdao, China
| | - Laura Cendron
- Department of Biology, University of Padova, 32121, Padova, Italy
| | - Thomas MacCarthy
- Department of Applied Mathematics and Statistics, Stony Brook University, Stony Brook, NY, USA
| | - Paola Venier
- Department of Biology, University of Padova, 32121, Padova, Italy.
| |
Collapse
|
12
|
Kim HJ, Jun JW, Giri SS, Yun S, Kim SG, Kim SW, Kang JW, Han SJ, Kwon J, Oh WT, Jeon HB, Chi C, Jeong D, Park SC. Mass mortality in Korean bay scallop (Argopecten irradians) associated with Ostreid Herpesvirus-1 μVar. Transbound Emerg Dis 2019; 66:1442-1448. [PMID: 30972971 DOI: 10.1111/tbed.13200] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 02/16/2019] [Accepted: 04/04/2019] [Indexed: 11/27/2022]
Abstract
Since November 2017, mass mortalities of larvae of bay scallop (Argopecten irradians) were reported in hatcheries located at the southern area of Republic of Korea. Over 90% of larvae aged 5-10 days sank to the bottom of the tank and died. The hatcheries could not produce spat, and thus artificial seed production industry incurred huge losses. We identified Ostreid Herpesvirus-1 μVar (OsHV-1 μVar) associated with mass mortality by PCR, sequencing and transmission electron microscopy (TEM). All the samples were positive for OsHV-1 μVar with 99% sequence identity to previously reported OsHV-1 μVar sequences. Partial sequence of ORF-4 of OsHV-1 detected in this study was more closely related to sequences isolated from Europe. This is the first report to confirm the mortality caused by an OsHV-1 infection in the bay scallop.
Collapse
Affiliation(s)
- Hyoun Joong Kim
- Laboratory of Aquatic Biomedicine, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul, Korea
| | - Jin Woo Jun
- Department of Aquaculture, Korea National College of Agriculture and Fisheries, Jeonju, Korea
| | - Sib Sankar Giri
- Laboratory of Aquatic Biomedicine, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul, Korea
| | - Saekil Yun
- Laboratory of Aquatic Biomedicine, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul, Korea
| | - Sang Guen Kim
- Laboratory of Aquatic Biomedicine, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul, Korea
| | - Sang Wha Kim
- Laboratory of Aquatic Biomedicine, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul, Korea
| | - Jeong Woo Kang
- Laboratory of Aquatic Biomedicine, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul, Korea
| | - Se Jin Han
- Laboratory of Aquatic Biomedicine, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul, Korea
| | - Jun Kwon
- Laboratory of Aquatic Biomedicine, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul, Korea
| | - Woo Taek Oh
- Laboratory of Aquatic Biomedicine, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul, Korea
| | - Hyung Bae Jeon
- Department of Life Science, Yeungnam University, Gyeongsan, Korea
| | - Cheng Chi
- Laboratory of Aquatic Nutrition and Ecology, College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China
| | - Dalsang Jeong
- Department of Aquaculture, Korea National College of Agriculture and Fisheries, Jeonju, Korea
| | - Se Chang Park
- Laboratory of Aquatic Biomedicine, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul, Korea
| |
Collapse
|
13
|
Long-range PCR and high-throughput sequencing of Ostreid herpesvirus 1 indicate high genetic diversity and complex evolution process. Virology 2019; 526:81-90. [DOI: 10.1016/j.virol.2018.09.026] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Revised: 09/29/2018] [Accepted: 09/29/2018] [Indexed: 12/11/2022]
|
14
|
Ostreid Herpesvirus-1 Infects Specific Hemocytes in Ark Clam, Scapharca broughtonii. Viruses 2018; 10:v10100529. [PMID: 30274142 PMCID: PMC6213218 DOI: 10.3390/v10100529] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Revised: 09/24/2018] [Accepted: 09/24/2018] [Indexed: 12/15/2022] Open
Abstract
High levels of ostreid herpesvirus 1 (OsHV-1) were detected in hemocytes of OsHV-1 infected mollusks. Mollusk hemocytes are comprised of different cell types with morphological and functional heterogeneity. Granular cells are considered the main immunocompetent hemocytes. This study aimed to ascertain if OsHV-1 infects specific types of hemocytes in ark clams. Types of hemocytes were first characterized through microexamination and flow cytometry. In addition to a large group of red cells, there were three types of recognizable granular cells in ark clams. Type II granular cells were mostly found with OsHV-1 infection by transmission electron microscope (TEM) examination, and represented the hemocyte type that was susceptible to OsHV-1 infection. The subcellular location of OsHV-1 particles in apoptotic type II granular cells was further analyzed. Some OsHV-1 particles were free inside the apoptotic cells, which may contribute to OsHV-1 transmission among cells in the host, some particles were also found enclosed inside apoptotic bodies. Apoptosis is an important part of the host defense system, but might also be hijacked by OsHV-1 as a strategy to escape host immune attack. Following this investigation, a primary culture of type II granular cells with OsHV-1 infection would facilitate the research on the interaction between OsHV-1 and mollusk hosts.
Collapse
|
15
|
Xin L, Huang B, Bai C, Wang C. Validation of housekeeping genes for quantitative mRNA expression analysis in OsHV-1 infected ark clam, Scapharca broughtonii. J Invertebr Pathol 2018; 155:44-51. [DOI: 10.1016/j.jip.2018.04.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Revised: 04/24/2018] [Accepted: 04/30/2018] [Indexed: 01/21/2023]
|
16
|
Abbadi M, Zamperin G, Gastaldelli M, Pascoli F, Rosani U, Milani A, Schivo A, Rossetti E, Turolla E, Gennari L, Toffan A, Arcangeli G, Venier P. Identification of a newly described OsHV-1 µvar from the North Adriatic Sea (Italy). J Gen Virol 2018; 99:693-703. [PMID: 29580370 PMCID: PMC5994699 DOI: 10.1099/jgv.0.001042] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The surveillance activities for abnormal bivalve mortality events in Italy include the diagnosis of ostreid herpesvirus type 1 (OsHV-1) in symptomatic oysters. OsHV-1-positive oysters (Crassostrea gigas) were used as a source for in vivo virus propagation and a virus-rich sample was selected to perform shotgun sequencing based on Illumina technology. Starting from this unpurified supernatant sample from gills and mantle, we generated 3.5 million reads (2×300 bp) and de novo assembled the whole genome of an Italian OsHV-1 microvariant (OsHV-1-PT). The OsHV-1-PT genome encodes 125 putative ORFs, 7 of which had not previously been predicted in other sequenced Malacoherpesviridae. Overall, OsHV-1-PT displays typical microvariant OsHV-1 genome features, while few polymorphisms (0.08 %) determine its uniqueness. As little is known about the genetic determinants of OsHV-1 virulence, comparing complete OsHV-1 genomes supports a better understanding of the virus pathogenicity and provides new insights into virus-host interactions.
Collapse
Affiliation(s)
- Miriam Abbadi
- Istituto Zooprofilattico Sperimentale Delle Venezie, Legnaro (PD), Italy.,Department of Biology, University of Padova, Padova (PD), Italy
| | - Gianpiero Zamperin
- Istituto Zooprofilattico Sperimentale Delle Venezie, Legnaro (PD), Italy
| | | | - Francesco Pascoli
- Istituto Zooprofilattico Sperimentale Delle Venezie, Legnaro (PD), Italy
| | - Umberto Rosani
- Department of Biology, University of Padova, Padova (PD), Italy
| | - Adelaide Milani
- Istituto Zooprofilattico Sperimentale Delle Venezie, Legnaro (PD), Italy
| | - Alessia Schivo
- Istituto Zooprofilattico Sperimentale Delle Venezie, Legnaro (PD), Italy
| | - Emanuele Rossetti
- Consorzio Cooperative Pescatori del Polesine, Scardovari (RO), Italy
| | | | | | - Anna Toffan
- Istituto Zooprofilattico Sperimentale Delle Venezie, Legnaro (PD), Italy
| | - Giuseppe Arcangeli
- Istituto Zooprofilattico Sperimentale Delle Venezie, Legnaro (PD), Italy
| | - Paola Venier
- Department of Biology, University of Padova, Padova (PD), Italy
| |
Collapse
|
17
|
Detection of Ostreid herpesvirus -1 microvariants in healthy Crassostrea gigas following disease events and their possible role as reservoirs of infection. J Invertebr Pathol 2017; 148:20-33. [DOI: 10.1016/j.jip.2017.05.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Revised: 04/30/2017] [Accepted: 05/08/2017] [Indexed: 02/07/2023]
|
18
|
Rosani U, Venier P. Oyster RNA-seq Data Support the Development of Malacoherpesviridae Genomics. Front Microbiol 2017; 8:1515. [PMID: 28848525 PMCID: PMC5552708 DOI: 10.3389/fmicb.2017.01515] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Accepted: 07/27/2017] [Indexed: 12/24/2022] Open
Abstract
The family of double-stranded DNA (dsDNA) Malacoherpesviridae includes viruses able to infect marine mollusks and detrimental for worldwide aquaculture production. Due to fast-occurring mortality and a lack of permissive cell lines, the available data on the few known Malacoherpesviridae provide only partial support for the study of molecular virus features, life cycle, and evolutionary history. Following thorough data mining of bivalve and gastropod RNA-seq experiments, we used more than five million Malacoherpesviridae reads to improve the annotation of viral genomes and to characterize viral InDels, nucleotide stretches, and SNPs. Both genome and protein domain analyses confirmed the evolutionary diversification and gene uniqueness of known Malacoherpesviridae. However, the presence of Malacoherpesviridae-like sequences integrated within genomes of phylogenetically distant invertebrates indicates broad diffusion of these viruses and indicates the need for confirmatory investigations. The manifest co-occurrence of OsHV-1 genotype variants in single RNA-seq samples of Crassostrea gigas provide further support for the Malacoherpesviridae diversification. In addition to simple sequence motifs inter-punctuating viral ORFs, recombination-inducing sequences were found to be enriched in the OsHV-1 and AbHV1-AUS genomes. Finally, the highly correlated expression of most viral ORFs in multiple oyster samples is consistent with the burst of viral proteins during the lytic phase.
Collapse
Affiliation(s)
| | - Paola Venier
- Department of Biology, University of PaduaPadua, Italy
| |
Collapse
|
19
|
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.
Collapse
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
| |
Collapse
|
20
|
Complete genome sequence of Ostreid herpesvirus type 1 µVar isolated during mortality events in the Pacific oyster Crassostrea gigas in France and Ireland. Virology 2017; 509:239-251. [PMID: 28672223 DOI: 10.1016/j.virol.2017.06.027] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Revised: 06/14/2017] [Accepted: 06/23/2017] [Indexed: 12/13/2022]
Abstract
Infections with Ostreid herpesvirus 1 (OsHV-1) microvariants in young Pacific oysters are associated with massive mortality events and significant economic losses. Previous studies, focusing on few regions of the genome, have revealed the genomic diversity of these genotypes with respect to the reference type. We used a NGS process to sequence the whole genome of the OsHV-1 µVar in infected individuals, collected during mortality events in France and Ireland. The final genome length of OsHV-1 µVar was approximately 205kbp, shorter than the reference genotype and the overall genome organisation resembled herpes simplex viruses. 94.4% similarity was observed with the OsHV-1 reference genotype. Large indels, including five deletions and three insertions were found to induce the loss and the addition of several ORFs, summed with codon substitutions in 64% of genes shared with the reference type. This diversity raises the question of the exact origin and evolution of OsHV-1 µVar.
Collapse
|
21
|
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.
Collapse
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.
| |
Collapse
|
22
|
Evans O, Paul-Pont I, Whittington RJ. Detection of ostreid herpesvirus 1 microvariant DNA in aquatic invertebrate species, sediment and other samples collected from the Georges River estuary, New South Wales, Australia. DISEASES OF AQUATIC ORGANISMS 2017; 122:247-255. [PMID: 28117303 DOI: 10.3354/dao03078] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Ostreid herpesvirus 1 microvariants (OsHV-1) present a serious threat to the Australian Crassostrea gigas industry. Of great concern is the propensity for mortality due to the virus recurring each season in farmed oysters. However, the source of the virus in recurrent outbreaks remains unclear. Reference strain ostreid herpesvirus 1 (OsHV-1 ref) and other related variants have been detected in several aquatic invertebrate species other than C. gigas in Europe, Asia and the USA. The aim of this study was to confirm the presence or absence of OsHV-1 in a range of opportunistically sampled aquatic invertebrate species inhabiting specific locations within the Georges River estuary in New South Wales, Australia. OsHV-1 DNA was detected in samples of wild C. gigas, Saccostrea glomerata, Anadara trapezia, mussels (Mytilus spp., Trichomya hirsuta), whelks (Batillaria australis or Pyrazus ebeninus) and barnacles Balanus spp. collected from several sites between October 2012 and April 2013. Viral loads in non-ostreid species were consistently low, as was the prevalence of OsHV-1 DNA detection. Viral concentrations were highest in wild C. gigas and S. glomerata; the prevalence of detectable OsHV-1 DNA in these oysters reached approximately 68 and 43%, respectively, at least once during the study. These species may be important to the transmission and/or persistence of OsHV-1 in endemically infected Australian estuaries.
Collapse
Affiliation(s)
- Olivia Evans
- Faculty of Veterinary Science, School of Life and Environmental Sciences, The University of Sydney, Camden, NSW 2570, Australia
| | | | | |
Collapse
|
23
|
Burioli EAV, Prearo M, Riina MV, Bona MC, Fioravanti ML, Arcangeli G, Houssin M. Ostreid herpesvirus type 1 genomic diversity in wild populations of Pacific oyster Crassostrea gigas from Italian coasts. J Invertebr Pathol 2016; 137:71-83. [PMID: 27234424 DOI: 10.1016/j.jip.2016.05.004] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Revised: 05/19/2016] [Accepted: 05/21/2016] [Indexed: 11/26/2022]
Abstract
Ostreid herpesvirus 1 (OsHV-1) is a significant pathogen affecting the young Pacific oyster Crassostrea gigas, worldwide. A new variant, OsHV-1 μVar, has been associated with recurrent mortality events in Europe since 2008. Epidemiological data collection is key for global risk assessment; however little is known about health status and genotypes present in European wild oyster beds. Most studies to date have involved only cultivated individuals during mortality events, and reported low genotype diversity. With this study, conducted along the Italian coasts, we investigated for the first time the presence of OsHV-1 in European natural oyster beds. Analysis of three genomic regions revealed the presence of at least nine different genotypes, including two variants close to the OsHV-1 reference, known since the early 1990s but with no European record reported since 2010, and highlights relevant genotype diversity in natural environment. Phylogenetic analysis distinguished two distinct clusters and geographical distribution of genotypes, with the exception of a variant very closely related to the μVar, which appeared the single genotype present in all the Adriatic sites. Interestingly, these wild symptom free populations could represent, in Europe, an accessible alternative to the import of OsHV-1-resistant oyster strains from the East Pacific, the native area of C. gigas, avoiding the high-risk of non-native marine species and new pathogen introductions.
Collapse
Affiliation(s)
- E A V Burioli
- Istituto Zooprofilattico Sperimentale del Piemonte, Liguria e Valle d'Aosta, Torino, Italy; Department of Veterinary Medical Sciences, Alma Mater Studiorum, Università di Bologna, Ozzano dell'Emilia, BO, Italy.
| | - M Prearo
- Istituto Zooprofilattico Sperimentale del Piemonte, Liguria e Valle d'Aosta, Torino, Italy
| | - M V Riina
- Istituto Zooprofilattico Sperimentale del Piemonte, Liguria e Valle d'Aosta, Torino, Italy
| | - M C Bona
- Istituto Zooprofilattico Sperimentale del Piemonte, Liguria e Valle d'Aosta, Torino, Italy
| | - M L Fioravanti
- Department of Veterinary Medical Sciences, Alma Mater Studiorum, Università di Bologna, Ozzano dell'Emilia, BO, Italy
| | - G Arcangeli
- Istituto Zooprofilattico Sperimentale delle Venezie, Legnaro, PD, Italy
| | - M Houssin
- Laboratoire Frank Duncombe LABEO, Caen, France
| |
Collapse
|
24
|
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.
Collapse
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
| |
Collapse
|
25
|
Detection of undescribed ostreid herpesvirus 1 (OsHV-1) specimens from Pacific oyster, Crassostrea gigas. J Invertebr Pathol 2015; 132:182-189. [PMID: 26527255 DOI: 10.1016/j.jip.2015.10.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Revised: 10/16/2015] [Accepted: 10/20/2015] [Indexed: 11/21/2022]
Abstract
The ostreid herpesvirus 1 (OsHV-1) and variants were implicated in mass mortality affecting the young Pacific cupped oysters, Crassostrea gigas, in European countries and those around the world. From 2008 onwards, oyster mortality had greatly increased on the French coast and was associated with the detection of a new OsHV-1 variant, entitled OsHV-1 μVar. The OsHV-1 μVar is predominant in oysters; however, other OsHV-1 variants have been detected in samples collected during mortality periods or collected out of mortality periods in France, Ireland, Spain, Portugal, Italy, Mexico, United States, South Korea, Australia, and New Zealand. A retrospective study conducted on 1047 OsHV-1 specimens sampled mainly in France between 2009 and 2012, revealed 17 undescribed OsHV-1 variants found in 65 oyster samples. These specimens presented point mutations situated downstream and upstream from the microsatellite area in the C region (ORF 4/5) which were different from the OsHV-1 reference and the OsHV-1 μVar. In the present work, investigation was performed to further characterize these OsHV-1 specimens by sequencing two habitually targeted regions to study genetic polymorphism of the virus: ORF 41/42 and ORF 35-38. An OsHV-1 variant detected in six oyster samples, contained a nucleotide substitution in the C region which impacted the amino acid sequence and might modify the function of the unknown protein encoding by ORF 4. For the ORF 41/42 region, only two specimens presented a synonymous mutation in comparison with the OsHV-1 μVar. All specimens contained the same deletion with the OsHV-1 μVar in ORF 35-38. Then, a phylogenetic analysis based on the C region was performed to investigate the distribution of undescribed specimens among 21 OsHV-1 DNA sequences notified in GenBank and collected from different countries (France, Japan, New Zealand, China, Ireland, and United States) between 1995 and 2012. All analyzed samples and the OsHV-1 μVar were placed in the same group, excepted for a Japan specimen. Our results contribute to improve the description of the genetic diversity of the OsHV-1 and the C region (ORF 4/5) appears to be a better target than ORF 42/42 and 35-38 to distinguish variants between themselves.
Collapse
|