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Vela-Avitúa S, Thorland I, Bakopoulos V, Papanna K, Dimitroglou A, Kottaras E, Leonidas P, Guinand B, Tsigenopoulos CS, Aslam ML. Genetic Basis for Resistance Against Viral Nervous Necrosis: GWAS and Potential of Genomic Prediction Explored in Farmed European Sea Bass ( Dicentrarchus labrax). Front Genet 2022; 13:804584. [PMID: 35401661 PMCID: PMC8992836 DOI: 10.3389/fgene.2022.804584] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Accepted: 02/22/2022] [Indexed: 11/13/2022] Open
Abstract
Viral nervous necrosis (VNN) is an infectious disease caused by the red-spotted grouper nervous necrosis virus (RGNNV) in European sea bass and is considered a serious concern for the aquaculture industry with fry and juveniles being highly susceptible. To understand the genetic basis for resistance against VNN, a survival phenotype through the challenge test against the RGNNV was recorded in populations from multiple year classes (YC2016 and YC2017). A total of 4,851 individuals from 181 families were tested, and a subset (n∼1,535) belonging to 122 families was genotyped using a ∼57K Affymetrix Axiom array. The survival against the RGNNV showed low to moderate heritability with observed scale estimates of 0.18 and 0.25 obtained using pedigree vs. genomic information, respectively. The genome-wide association analysis showed a strong signal of quantitative trait loci (QTL) at LG12 which explained ∼33% of the genetic variance. The QTL region contained multiple genes (ITPK1, PLK4, HSPA4L, REEP1, CHMP2, MRPL35, and SCUBE) with HSPA4L and/or REEP1 genes being highly relevant with a likely effect on host response in managing disease-associated symptoms. The results on the accuracy of predicting breeding values presented 20–43% advantage in accuracy using genomic over pedigree-based information which varied across model types and applied validation schemes.
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Affiliation(s)
- Sergio Vela-Avitúa
- Benchmark Genetics Norway AS (formerly Akvaforsk Genetics Center AS), Sunndalsøra, Norway
| | - Ingunn Thorland
- Benchmark Genetics Norway AS (formerly Akvaforsk Genetics Center AS), Sunndalsøra, Norway
| | - Vasileios Bakopoulos
- Laboratory of Ichthyology, Aquaculture and Diseases of Aquatic Animals, Department of Marine Sciences, University of The Aegean, Mytilene, Greece
| | | | | | | | | | - Bruno Guinand
- CNRS, IRD, EPHE, ISEM, Université de Montpellier, Montpellier, France
| | - Costas S Tsigenopoulos
- Biotechnology and Aquaculture (IMBBC), Hellenic Centre for Marine Research (HCMR), Institute of Marine Biology, Heraklion, Greece
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Pooley CM, Marion G, Bishop SC, Bailey RI, Doeschl-Wilson AB. Estimating individuals' genetic and non-genetic effects underlying infectious disease transmission from temporal epidemic data. PLoS Comput Biol 2020; 16:e1008447. [PMID: 33347459 PMCID: PMC7785229 DOI: 10.1371/journal.pcbi.1008447] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 01/05/2021] [Accepted: 10/16/2020] [Indexed: 12/16/2022] Open
Abstract
Individuals differ widely in their contribution to the spread of infection within and across populations. Three key epidemiological host traits affect infectious disease spread: susceptibility (propensity to acquire infection), infectivity (propensity to transmit infection to others) and recoverability (propensity to recover quickly). Interventions aiming to reduce disease spread may target improvement in any one of these traits, but the necessary statistical methods for obtaining risk estimates are lacking. In this paper we introduce a novel software tool called SIRE (standing for "Susceptibility, Infectivity and Recoverability Estimation"), which allows for the first time simultaneous estimation of the genetic effect of a single nucleotide polymorphism (SNP), as well as non-genetic influences on these three unobservable host traits. SIRE implements a flexible Bayesian algorithm which accommodates a wide range of disease surveillance data comprising any combination of recorded individual infection and/or recovery times, or disease diagnostic test results. Different genetic and non-genetic regulations and data scenarios (representing realistic recording schemes) were simulated to validate SIRE and to assess their impact on the precision, accuracy and bias of parameter estimates. This analysis revealed that with few exceptions, SIRE provides unbiased, accurate parameter estimates associated with all three host traits. For most scenarios, SNP effects associated with recoverability can be estimated with highest precision, followed by susceptibility. For infectivity, many epidemics with few individuals give substantially more statistical power to identify SNP effects than the reverse. Importantly, precise estimates of SNP and other effects could be obtained even in the case of incomplete, censored and relatively infrequent measurements of individuals' infection or survival status, albeit requiring more individuals to yield equivalent precision. SIRE represents a new tool for analysing a wide range of experimental and field disease data with the aim of discovering and validating SNPs and other factors controlling infectious disease transmission.
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Affiliation(s)
- Christopher M. Pooley
- The Roslin Institute, Midlothian, United Kingdom
- Biomathematics and Statistics Scotland, Edinburgh, United Kingdom
- * E-mail:
| | - Glenn Marion
- Biomathematics and Statistics Scotland, Edinburgh, United Kingdom
| | | | - Richard I. Bailey
- The Roslin Institute, Midlothian, United Kingdom
- Department of Ecology and Vertebrate Zoology, Faculty of Biology and Environmental Protection, University of Łódź, Lodz, Poland
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3
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Zhou Q, Su Z, Li Y, Liu Y, Wang L, Lu S, Wang S, Gan T, Liu F, Zhou X, Wei M, Liu G, Chen S. Genome-Wide Association Mapping and Gene Expression Analyses Reveal Genetic Mechanisms of Disease Resistance Variations in Cynoglossus semilaevis. Front Genet 2019; 10:1167. [PMID: 31824570 PMCID: PMC6880758 DOI: 10.3389/fgene.2019.01167] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Accepted: 10/23/2019] [Indexed: 12/15/2022] Open
Abstract
The sustainable development of aquaculture has been impeded by infectious diseases worldwide. However, the genomic architecture and the genetic basis underlying the disease resistance remain poorly understood, which severely hampers both the understanding of the evolution of fish disease resistance traits and the prevention of these diseases in the aquaculture community. Cynoglossus semilaevis is a representative and commercially-important flatfish species. Here we combined genome-wide association study and Fst and nucleotide diversity filtration to identify loci important for the disease resistance. Based on 1,016,774 single-nucleotide polymorphisms (SNPs) identified from 650 Gb genome resequencing data of 505 individuals, we detected 33 SNPs significantly associated with disease resistance and 79 candidate regions after filtration steps. Both the allele frequencies and genotype frequencies of the associated loci were significantly different between the resistant and susceptible fish, suggesting a role in the genetic basis of disease resistance. The SNP with strongest association with disease resistance was located in Chr 17, at 145 bp upstream of fblx19 gene, and overlapped with the major quantitative trait locus previously identified. Several genes, such as plekha7, nucb2, and fgfr2, were also identified to potentially play roles in the disease resistance. Furthermore, the expression of some associating genes were likely under epigenetic regulations between the bacterial resistant and susceptible families. These results provide insights into the mechanism that enable variation of disease resistance to bacterial pathogen infection. The identified polymorphisms and genes are valuable targets and molecular resources for disease resistance and other traits, and for advanced breeding practice for superior germplasm in fish aquaculture.
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Affiliation(s)
- Qian Zhou
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences/Key Laboratory for Sustainable Development of Marine Fisheries, Ministry of Agriculture, Qingdao, China.,Laboratory for Marine Fisheries Science and Food Production Processes, Pilot National Laboratory for Marine Science and Technology, Qingdao, China.,Key Laboratory for Marine Fishery Biotechnology and Genetic Breeding, Qingdao, China
| | - Zhencheng Su
- Novogene Bioinformatics Technology Co., Ltd, Beijing, China
| | - Yangzhen Li
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences/Key Laboratory for Sustainable Development of Marine Fisheries, Ministry of Agriculture, Qingdao, China
| | - Yang Liu
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences/Key Laboratory for Sustainable Development of Marine Fisheries, Ministry of Agriculture, Qingdao, China
| | - Lei Wang
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences/Key Laboratory for Sustainable Development of Marine Fisheries, Ministry of Agriculture, Qingdao, China
| | - Sheng Lu
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences/Key Laboratory for Sustainable Development of Marine Fisheries, Ministry of Agriculture, Qingdao, China
| | - Shuanyan Wang
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences/Key Laboratory for Sustainable Development of Marine Fisheries, Ministry of Agriculture, Qingdao, China
| | - Tian Gan
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences/Key Laboratory for Sustainable Development of Marine Fisheries, Ministry of Agriculture, Qingdao, China
| | - Feng Liu
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences/Key Laboratory for Sustainable Development of Marine Fisheries, Ministry of Agriculture, Qingdao, China
| | - Xun Zhou
- Novogene Bioinformatics Technology Co., Ltd, Beijing, China
| | - Min Wei
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences/Key Laboratory for Sustainable Development of Marine Fisheries, Ministry of Agriculture, Qingdao, China
| | - Guangjian Liu
- Novogene Bioinformatics Technology Co., Ltd, Beijing, China
| | - Songlin Chen
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences/Key Laboratory for Sustainable Development of Marine Fisheries, Ministry of Agriculture, Qingdao, China.,Laboratory for Marine Fisheries Science and Food Production Processes, Pilot National Laboratory for Marine Science and Technology, Qingdao, China.,Key Laboratory for Marine Fishery Biotechnology and Genetic Breeding, Qingdao, China
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Salem M, Al-Tobasei R, Ali A, Lourenco D, Gao G, Palti Y, Kenney B, Leeds TD. Genome-Wide Association Analysis With a 50K Transcribed Gene SNP-Chip Identifies QTL Affecting Muscle Yield in Rainbow Trout. Front Genet 2018; 9:387. [PMID: 30283492 PMCID: PMC6157414 DOI: 10.3389/fgene.2018.00387] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Accepted: 08/27/2018] [Indexed: 11/13/2022] Open
Abstract
Detection of coding/functional SNPs that change the biological function of a gene may lead to identification of putative causative alleles within QTL regions and discovery of genetic markers with large effects on phenotypes. This study has two-fold objectives, first to develop, and validate a 50K transcribed gene SNP-chip using RNA-Seq data. To achieve this objective, two bioinformatics pipelines, GATK and SAMtools, were used to identify ~21K transcribed SNPs with allelic imbalances associated with important aquaculture production traits including body weight, muscle yield, muscle fat content, shear force, and whiteness in addition to resistance/susceptibility to bacterial cold-water disease (BCWD). SNPs ere identified from pooled RNA-Seq data collected from ~620 fish, representing 98 families from growth- and 54 families from BCWD-selected lines with divergent phenotypes. In addition, ~29K transcribed SNPs without allelic-imbalances were strategically added to build a 50K Affymetrix SNP-chip. SNPs selected included two SNPs per gene from 14K genes and ~5K non-synonymous SNPs. The SNP-chip was used to genotype 1728 fish. The average SNP calling-rate for samples passing quality control (QC; 1,641 fish) was ≥ 98.5%. The second objective of this study was to test the feasibility of using the new SNP-chip in GWA (Genome-wide association) analysis to identify QTL explaining muscle yield variance. GWA study on 878 fish (representing 197 families from 2 consecutive generations) with muscle yield phenotypes and genotyped for 35K polymorphic markers (passing QC) identified several QTL regions explaining together up to 28.40% of the additive genetic variance for muscle yield in this rainbow trout population. The most significant QTLs were on chromosomes 14 and 16 with 12.71 and 10.49% of the genetic variance, respectively. Many of the annotated genes in the QTL regions were previously reported as important regulators of muscle development and cell signaling. No major QTLs were identified in a previous GWA study using a 57K genomic SNP chip on the same fish population. These results indicate improved detection power of the transcribed gene SNP-chip in the target trait and population, allowing identification of large-effect QTLs for important traits in rainbow trout.
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Affiliation(s)
- Mohamed Salem
- Department of Biology and Molecular Biosciences Program, Middle Tennessee State University, Murfreesboro, TN, United States.,Computational Science Program, Middle Tennessee State University, Murfreesboro, TN, United States
| | - Rafet Al-Tobasei
- Computational Science Program, Middle Tennessee State University, Murfreesboro, TN, United States.,Department of Biostatistics, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Ali Ali
- Department of Biology and Molecular Biosciences Program, Middle Tennessee State University, Murfreesboro, TN, United States
| | - Daniela Lourenco
- Department of Animal and Dairy Science, University of Georgia, Athens, GA, United States
| | - Guangtu Gao
- National Center for Cool and Cold Water Aquaculture, USDA Agricultural Research Service, Kearneysville, WV, United States
| | - Yniv Palti
- National Center for Cool and Cold Water Aquaculture, USDA Agricultural Research Service, Kearneysville, WV, United States
| | - Brett Kenney
- Division of Animal and Nutritional Science, West Virginia University, Morgantown, WV, United States
| | - Timothy D Leeds
- National Center for Cool and Cold Water Aquaculture, USDA Agricultural Research Service, Kearneysville, WV, United States
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Teleosts Genomics: Progress and Prospects in Disease Prevention and Control. Int J Mol Sci 2018; 19:ijms19041083. [PMID: 29617353 PMCID: PMC5979277 DOI: 10.3390/ijms19041083] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2018] [Revised: 03/11/2018] [Accepted: 03/29/2018] [Indexed: 12/26/2022] Open
Abstract
Genome wide studies based on conventional molecular tools and upcoming omics technologies are beginning to gain functional applications in the control and prevention of diseases in teleosts fish. Herein, we provide insights into current progress and prospects in the use genomics studies for the control and prevention of fish diseases. Metagenomics has emerged to be an important tool used to identify emerging infectious diseases for the timely design of rational disease control strategies, determining microbial compositions in different aquatic environments used for fish farming and the use of host microbiota to monitor the health status of fish. Expounding the use of antimicrobial peptides (AMPs) as therapeutic agents against different pathogens as well as elucidating their role in tissue regeneration is another vital aspect of genomics studies that had taken precedent in recent years. In vaccine development, prospects made include the identification of highly immunogenic proteins for use in recombinant vaccine designs as well as identifying gene signatures that correlate with protective immunity for use as benchmarks in optimizing vaccine efficacy. Progress in quantitative trait loci (QTL) mapping is beginning to yield considerable success in identifying resistant traits against some of the highly infectious diseases that have previously ravaged the aquaculture industry. Altogether, the synopsis put forth shows that genomics studies are beginning to yield positive contribution in the prevention and control of fish diseases in aquaculture.
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Genomic Prediction Accuracy for Resistance Against Piscirickettsia salmonis in Farmed Rainbow Trout. G3-GENES GENOMES GENETICS 2018; 8:719-726. [PMID: 29255117 PMCID: PMC5919750 DOI: 10.1534/g3.117.300499] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Salmonid rickettsial syndrome (SRS), caused by the intracellular bacterium Piscirickettsia salmonis, is one of the main diseases affecting rainbow trout (Oncorhynchus mykiss) farming. To accelerate genetic progress, genomic selection methods can be used as an effective approach to control the disease. The aims of this study were: (i) to compare the accuracy of estimated breeding values using pedigree-based best linear unbiased prediction (PBLUP) with genomic BLUP (GBLUP), single-step GBLUP (ssGBLUP), Bayes C, and Bayesian Lasso (LASSO); and (ii) to test the accuracy of genomic prediction and PBLUP using different marker densities (0.5, 3, 10, 20, and 27 K) for resistance against P. salmonis in rainbow trout. Phenotypes were recorded as number of days to death (DD) and binary survival (BS) from 2416 fish challenged with P. salmonis. A total of 1934 fish were genotyped using a 57 K single-nucleotide polymorphism (SNP) array. All genomic prediction methods achieved higher accuracies than PBLUP. The relative increase in accuracy for different genomic models ranged from 28 to 41% for both DD and BS at 27 K SNP. Between different genomic models, the highest relative increase in accuracy was obtained with Bayes C (∼40%), where 3 K SNP was enough to achieve a similar accuracy to that of the 27 K SNP for both traits. For resistance against P. salmonis in rainbow trout, we showed that genomic predictions using GBLUP, ssGBLUP, Bayes C, and LASSO can increase accuracy compared with PBLUP. Moreover, it is possible to use relatively low-density SNP panels for genomic prediction without compromising accuracy predictions for resistance against P. salmonis in rainbow trout.
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Ariede RB, Freitas MV, Hata ME, Mastrochirico-Filho VA, Pilarski F, Batlouni SR, Porto-Foresti F, Hashimoto DT. Microsatellites Associated with Growth Performance and Analysis of Resistance to Aeromonas hydrophila in Tambaqui Colossoma macropomum. Front Genet 2018; 9:3. [PMID: 29403527 PMCID: PMC5778134 DOI: 10.3389/fgene.2018.00003] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Accepted: 01/04/2018] [Indexed: 01/28/2023] Open
Abstract
Tambaqui, Colossoma macropomum, is the main native fish species produced in Brazil, and is an important species for genetic improvement in aquaculture. In addition, breeding studies on this species can be optimized with the use of molecular markers associated with productive phenotypes. The objective of the present study was to test the performance of growth traits and resistance to the bacteria, Aeromonas hydrophila, in association with microsatellite markers in C. macropomum. In this study, three full-sib families were subjected to bacterial challenge and morphometric growth assessments. Tambaqui families subjected to the bacterial challenge differed significantly in death time and mortality rate. There was, however, no association between resistance to bacteria and microsatellite markers. In relation to growth traits, we observed a marker/phenotype association in two microsatellites. The marker in the 6b isoform x5 gene (TNCRC6b) was associated with length, whereas an anonymous marker was associated with height. The present study highlighted the evaluation of molecular markers associated with growth traits, and can serve as the basis for future marker-assisted selection (MAS) of tambaqui.
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Affiliation(s)
- Raquel B Ariede
- Aquaculture Center of Unesp, São Paulo State University (Unesp), Jaboticabal, Brazil
| | - Milena V Freitas
- Aquaculture Center of Unesp, São Paulo State University (Unesp), Jaboticabal, Brazil
| | - Milene E Hata
- Aquaculture Center of Unesp, São Paulo State University (Unesp), Jaboticabal, Brazil
| | | | - Fabiana Pilarski
- Aquaculture Center of Unesp, São Paulo State University (Unesp), Jaboticabal, Brazil
| | - Sergio R Batlouni
- Aquaculture Center of Unesp, São Paulo State University (Unesp), Jaboticabal, Brazil
| | | | - Diogo T Hashimoto
- Aquaculture Center of Unesp, São Paulo State University (Unesp), Jaboticabal, Brazil
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8
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Mutoloki S, Jøssund TB, Ritchie G, Munang'andu HM, Evensen Ø. Infectious Pancreatic Necrosis Virus Causing Clinical and Subclinical Infections in Atlantic Salmon Have Different Genetic Fingerprints. Front Microbiol 2016; 7:1393. [PMID: 27630636 PMCID: PMC5006305 DOI: 10.3389/fmicb.2016.01393] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Accepted: 08/23/2016] [Indexed: 01/17/2023] Open
Abstract
Infectious pancreatic necrosis virus (IPNV) is the causative agent of IPN, an important disease of salmonids. IPNV infections result in either sub-clinical or overt disease and the basis of this difference is not well-understood. The objective of the present study was to determine the VP2 gene of the virus associated with the different forms of clinical manifestation. Groups of Atlantic salmon (Salmo salar L.) reared in farms located in different IPN disease pressures were monitored from brood stock until grow-out over a 3 year period. Hatcheries A1 and B1 as well as cooperating seawater farms were located in a low disease risk area while hatcheries A2 and B2 as well as their cooperating seawater farms were in high IPN risk areas. Samples including eggs, milt, whole fry, kidney depending on the stage of production were collected during outbreaks or in apparently healthy populations where no outbreaks occurred. The virus was re-isolated in CHSE cells and the VP2 gene amplified by RT-PCR followed by sequencing. During the freshwater stage, there were no disease outbreaks at hatcheries A1, A2, and B1 (except in one fish group that originated from hatchery B2), although IPNV was isolated from some of the fish groups at all 3 hatcheries. By contrast, all fish groups at hatchery B2 suffered IPN outbreaks. In seawater, only groups of fish originating from hatchery A1 had no IPN outbreaks albeit virus being isolated from the fish. On the other hand, fish originating from hatcheries A2, B1, and B2 experienced outbreaks in seawater. The VP2 amino acid fingerprint of the virus associated with subclinical infections from A1 and co-operating seawater sites was V64A137P217T221A247N252S281D282E319. By contrast, all virus isolates associated with clinical infections had the motif I64T137T217A221T247V252T281N282A319, where underlined amino acids represent the avirulent and highly virulent motif, respectively. Phylogenetic analysis of amino acid sequences showed 2 clades, one of isolates associated with subclinical infections (from A1 and cooperating seawater farms) and the other of isolates from fish with overt disease (all other sites). Furthermore, the clustering pattern of isolates suggests more circulation of virus within fish groups rather than between them.
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Affiliation(s)
- Stephen Mutoloki
- Faculty of Veterinary Medicine and Biosciences, Norwegian University of Life Sciences Oslo, Norway
| | | | | | - Hetron M Munang'andu
- Faculty of Veterinary Medicine and Biosciences, Norwegian University of Life Sciences Oslo, Norway
| | - Øystein Evensen
- Faculty of Veterinary Medicine and Biosciences, Norwegian University of Life Sciences Oslo, Norway
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Fine mapping QTL for resistance to VNN disease using a high-density linkage map in Asian seabass. Sci Rep 2016; 6:32122. [PMID: 27555039 PMCID: PMC4995370 DOI: 10.1038/srep32122] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Accepted: 08/02/2016] [Indexed: 12/30/2022] Open
Abstract
Asian seabass has suffered from viral nervous necrosis (VNN) disease. Our previous study has mapped quantitative trait loci (QTL) for resistance to VNN disease. To fine map these QTL and identify causative genes, we identified 6425 single nucleotide polymorphisms (SNPs) from 85 dead and 94 surviving individuals. Combined with 155 microsatellites, we constructed a genetic map consisting of 24 linkage groups (LGs) containing 3000 markers, with an average interval of 1.27 cM. We mapped one significant and three suggestive QTL with phenotypic variation explained (PVE) of 8.3 to 11.0%, two significant and two suggestive QTL with PVE of 7.8 to 10.9%, for resistance in three LGs and survival time in four LGs, respectively. Further analysis one QTL with the largest effect identified protocadherin alpha-C 2-like (Pcdhac2) as the possible candidate gene. Association study in 43 families with 1127 individuals revealed a 6 bp insertion-deletion was significantly associated with disease resistance. qRT-PCR showed the expression of Pcdhac2 was significantly induced in the brain, muscle and skin after nervous necrosis virus (NNV) infection. Our results could facilitate marker-assisted selection (MAS) for resistance to NNV in Asian seabass and set up the basis for functional analysis of the potential causative gene for resistance.
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10
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Robledo D, Taggart JB, Ireland JH, McAndrew BJ, Starkey WG, Haley CS, Hamilton A, Guy DR, Mota-Velasco JC, Gheyas AA, Tinch AE, Verner-Jeffreys DW, Paley RK, Rimmer GSE, Tew IJ, Bishop SC, Bron JE, Houston RD. Gene expression comparison of resistant and susceptible Atlantic salmon fry challenged with Infectious Pancreatic Necrosis virus reveals a marked contrast in immune response. BMC Genomics 2016; 17:279. [PMID: 27066778 PMCID: PMC4827185 DOI: 10.1186/s12864-016-2600-y] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 03/22/2016] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND Infectious Pancreatic Necrosis (IPN) is a highly contagious birnavirus disease of farmed salmonid fish, which often causes high levels of morbidity and mortality. A large host genetic component to resistance has been previously described for Atlantic salmon (Salmo salar L.), which mediates high mortality rates in some families and zero mortality in others. However, the molecular and immunological basis for this resistance is not yet fully known. This manuscript describes a global comparison of the gene expression profiles of resistant and susceptible Atlantic salmon fry following challenge with the IPN virus. RESULTS Salmon fry from two IPNV-resistant and two IPNV-susceptible full sibling families were challenged with the virus and sampled at 1 day, 7 days and 20 days post-challenge. Significant viral titre was observed in both resistant and susceptible fish at all timepoints, although generally at higher levels in susceptible fish. Gene expression profiles combined with gene ontology and pathway analyses demonstrated that while a clear immune response was observed in both resistant and susceptible fish, there were striking differences between the two phenotypes. The susceptible fish showed marked up-regulation of genes related to cytokine activity and inflammatory response that evidently failed to protect against the virus. In contrast, the resistant fish demonstrated a less pronounced immune response including up-regulation of genes relating to the M2 macrophage system. CONCLUSIONS While only the susceptible phenotype shows appreciable mortality levels, both resistant and susceptible fish can become infected with IPNV. Susceptible fish are characterized by a much larger, yet ineffective, immune response, largely related to cytokine and inflammatory systems. Resistant fish demonstrate a more moderate, putative macrophage-mediated inflammatory response, which may contribute to their survival.
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Affiliation(s)
- Diego Robledo
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Midlothian, EH25 9RG, UK.,Departamento de Genética, Facultad de Biología, Universidad de Santiago de Compostela, Santiago de Compostela, 15782, Spain
| | - John B Taggart
- Institute of Aquaculture, School of Natural Sciences, University of Stirling, Stirling, FK9 4LA, UK
| | - Jacqueline H Ireland
- Institute of Aquaculture, School of Natural Sciences, University of Stirling, Stirling, FK9 4LA, UK
| | - Brendan J McAndrew
- Institute of Aquaculture, School of Natural Sciences, University of Stirling, Stirling, FK9 4LA, UK
| | - William G Starkey
- Institute of Aquaculture, School of Natural Sciences, University of Stirling, Stirling, FK9 4LA, UK
| | - Chris S Haley
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Midlothian, EH25 9RG, UK
| | - Alastair Hamilton
- Landcatch Natural Selection Ltd., 15 Beta Centre, Stirling University Innovation Park, Stirling, FK9 4NF, UK
| | - Derrick R Guy
- Landcatch Natural Selection Ltd., 15 Beta Centre, Stirling University Innovation Park, Stirling, FK9 4NF, UK
| | - Jose C Mota-Velasco
- Landcatch Natural Selection Ltd., 15 Beta Centre, Stirling University Innovation Park, Stirling, FK9 4NF, UK
| | - Almas A Gheyas
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Midlothian, EH25 9RG, UK.,Landcatch Natural Selection Ltd., 15 Beta Centre, Stirling University Innovation Park, Stirling, FK9 4NF, UK
| | - Alan E Tinch
- Landcatch Natural Selection Ltd., 15 Beta Centre, Stirling University Innovation Park, Stirling, FK9 4NF, UK
| | | | - Richard K Paley
- Centre for Environment, Fisheries and Aquaculture Science (Cefas), Weymouth, DT4 8UB, UK
| | - Georgina S E Rimmer
- Centre for Environment, Fisheries and Aquaculture Science (Cefas), Weymouth, DT4 8UB, UK
| | - Ian J Tew
- Centre for Environment, Fisheries and Aquaculture Science (Cefas), Weymouth, DT4 8UB, UK
| | - Stephen C Bishop
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Midlothian, EH25 9RG, UK
| | - James E Bron
- Institute of Aquaculture, School of Natural Sciences, University of Stirling, Stirling, FK9 4LA, 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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Geng X, Sha J, Liu S, Bao L, Zhang J, Wang R, Yao J, Li C, Feng J, Sun F, Sun L, Jiang C, Zhang Y, Chen A, Dunham R, Zhi D, Liu Z. A genome-wide association study in catfish reveals the presence of functional hubs of related genes within QTLs for columnaris disease resistance. BMC Genomics 2015; 16:196. [PMID: 25888203 PMCID: PMC4372039 DOI: 10.1186/s12864-015-1409-4] [Citation(s) in RCA: 89] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Accepted: 02/27/2015] [Indexed: 11/16/2022] Open
Abstract
Background Columnaris causes severe mortalities among many different wild and cultured freshwater fish species, but understanding of host resistance is lacking. Catfish, the primary aquaculture species in the United States, serves as a great model for the analysis of host resistance against columnaris disease. Channel catfish in general is highly resistant to the disease while blue catfish is highly susceptible. F2 generation of hybrids can be produced where phenotypes and genotypes are segregating, providing a useful system for QTL analysis. To identify genes associated with columnaris resistance, we performed a genome-wide association study (GWAS) using the catfish 250 K SNP array with 340 backcross progenies derived from crossing female channel catfish (Ictalurus punctatus) with male F1 hybrid catfish (female channel catfish I. punctatus × male blue catfish I. furcatus). Results A genomic region on linkage group 7 was found to be significantly associated with columnaris resistance. Within this region, five have known functions in immunity, including pik3r3b, cyld-like, adcyap1r1, adcyap1r1-like, and mast2. In addition, 3 additional suggestively associated QTL regions were identified on linkage groups 7, 12, and 14. The resistant genotypes on the QTLs of linkage groups 7 and 12 were found to be homozygous with both alleles being derived from channel catfish. The paralogs of the candidate genes in the suggestively associated QTL of linkage group 12 were found on the QTLs of linkage group 7. Many candidate genes on the four associated regions are involved in PI3K pathway that is known to be required by many bacteria for efficient entry into the host. Conclusion The GWAS revealed four QTLs associated with columnaris resistance in catfish. Strikingly, the candidate genes may be arranged as functional hubs; the candidate genes within the associated QTLs on linkage groups 7 and 12 are not only co-localized, but also functionally related, with many of them being involved in the PI3K signal transduction pathway, suggesting its importance for columnaris resistance.
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Affiliation(s)
- Xin Geng
- Fish Molecular Genetics and Biotechnology Laboratory, Aquatic Genomics Unit, School of Fisheries, Aquaculture and Aquatic Sciences and Program of Cell and Molecular Biosciences, Auburn University, Auburn, AL, 36849, USA.
| | - Jin Sha
- Department of Biostatistics, University of Alabama at Birmingham, Birmingham, AL, 35294, USA.
| | - Shikai Liu
- Fish Molecular Genetics and Biotechnology Laboratory, Aquatic Genomics Unit, School of Fisheries, Aquaculture and Aquatic Sciences and Program of Cell and Molecular Biosciences, Auburn University, Auburn, AL, 36849, USA.
| | - Lisui Bao
- Fish Molecular Genetics and Biotechnology Laboratory, Aquatic Genomics Unit, School of Fisheries, Aquaculture and Aquatic Sciences and Program of Cell and Molecular Biosciences, Auburn University, Auburn, AL, 36849, USA.
| | - Jiaren Zhang
- Fish Molecular Genetics and Biotechnology Laboratory, Aquatic Genomics Unit, School of Fisheries, Aquaculture and Aquatic Sciences and Program of Cell and Molecular Biosciences, Auburn University, Auburn, AL, 36849, USA.
| | - Ruijia Wang
- Fish Molecular Genetics and Biotechnology Laboratory, Aquatic Genomics Unit, School of Fisheries, Aquaculture and Aquatic Sciences and Program of Cell and Molecular Biosciences, Auburn University, Auburn, AL, 36849, USA.
| | - Jun Yao
- Fish Molecular Genetics and Biotechnology Laboratory, Aquatic Genomics Unit, School of Fisheries, Aquaculture and Aquatic Sciences and Program of Cell and Molecular Biosciences, Auburn University, Auburn, AL, 36849, USA.
| | - Chao Li
- Fish Molecular Genetics and Biotechnology Laboratory, Aquatic Genomics Unit, School of Fisheries, Aquaculture and Aquatic Sciences and Program of Cell and Molecular Biosciences, Auburn University, Auburn, AL, 36849, USA.
| | - Jianbin Feng
- Fish Molecular Genetics and Biotechnology Laboratory, Aquatic Genomics Unit, School of Fisheries, Aquaculture and Aquatic Sciences and Program of Cell and Molecular Biosciences, Auburn University, Auburn, AL, 36849, USA.
| | - Fanyue Sun
- Fish Molecular Genetics and Biotechnology Laboratory, Aquatic Genomics Unit, School of Fisheries, Aquaculture and Aquatic Sciences and Program of Cell and Molecular Biosciences, Auburn University, Auburn, AL, 36849, USA.
| | - Luyang Sun
- Fish Molecular Genetics and Biotechnology Laboratory, Aquatic Genomics Unit, School of Fisheries, Aquaculture and Aquatic Sciences and Program of Cell and Molecular Biosciences, Auburn University, Auburn, AL, 36849, USA.
| | - Chen Jiang
- Fish Molecular Genetics and Biotechnology Laboratory, Aquatic Genomics Unit, School of Fisheries, Aquaculture and Aquatic Sciences and Program of Cell and Molecular Biosciences, Auburn University, Auburn, AL, 36849, USA.
| | - Yu Zhang
- Fish Molecular Genetics and Biotechnology Laboratory, Aquatic Genomics Unit, School of Fisheries, Aquaculture and Aquatic Sciences and Program of Cell and Molecular Biosciences, Auburn University, Auburn, AL, 36849, USA.
| | - Ailu Chen
- Fish Molecular Genetics and Biotechnology Laboratory, Aquatic Genomics Unit, School of Fisheries, Aquaculture and Aquatic Sciences and Program of Cell and Molecular Biosciences, Auburn University, Auburn, AL, 36849, USA.
| | - Rex Dunham
- Fish Molecular Genetics and Biotechnology Laboratory, Aquatic Genomics Unit, School of Fisheries, Aquaculture and Aquatic Sciences and Program of Cell and Molecular Biosciences, Auburn University, Auburn, AL, 36849, USA.
| | - Degui Zhi
- Department of Biostatistics, University of Alabama at Birmingham, Birmingham, AL, 35294, USA.
| | - Zhanjiang Liu
- Fish Molecular Genetics and Biotechnology Laboratory, Aquatic Genomics Unit, School of Fisheries, Aquaculture and Aquatic Sciences and Program of Cell and Molecular Biosciences, Auburn University, Auburn, AL, 36849, USA.
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12
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Yáñez JM, Houston RD, Newman S. Genetics and genomics of disease resistance in salmonid species. Front Genet 2014; 5:415. [PMID: 25505486 PMCID: PMC4245001 DOI: 10.3389/fgene.2014.00415] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Accepted: 11/06/2014] [Indexed: 11/15/2022] Open
Abstract
Infectious and parasitic diseases generate large economic losses in salmon farming. A feasible and sustainable alternative to prevent disease outbreaks may be represented by genetic improvement for disease resistance. To include disease resistance into the breeding goal, prior knowledge of the levels of genetic variation for these traits is required. Furthermore, the information from the genetic architecture and molecular factors involved in resistance against diseases may be used to accelerate the genetic progress for these traits. In this regard, marker assisted selection and genomic selection are approaches which incorporate molecular information to increase the accuracy when predicting the genetic merit of selection candidates. In this article we review and discuss key aspects related to disease resistance in salmonid species, from both a genetic and genomic perspective, with emphasis in the applicability of disease resistance traits into breeding programs in salmonids.
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Affiliation(s)
- José M Yáñez
- Faculty of Veterinary and Animal Sciences, University of Chile Santiago, Chile ; Aquainnovo, Puerto Montt Chile
| | - Ross D Houston
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh Midlothian, UK
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13
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Wiens GD, Vallejo RL, Leeds TD, Palti Y, Hadidi S, Liu S, Evenhuis JP, Welch TJ, Rexroad CE. Assessment of genetic correlation between bacterial cold water disease resistance and spleen index in a domesticated population of rainbow trout: identification of QTL on chromosome Omy19. PLoS One 2013; 8:e75749. [PMID: 24130739 PMCID: PMC3794016 DOI: 10.1371/journal.pone.0075749] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Accepted: 08/20/2013] [Indexed: 11/18/2022] Open
Abstract
Selective breeding of animals for increased disease resistance is an effective strategy to reduce mortality in aquaculture. However, implementation of selective breeding programs is limited by an incomplete understanding of host resistance traits. We previously reported results of a rainbow trout selection program that demonstrated increased survival following challenge with Flavobacterium psychrophilum, the causative agent of bacterial cold water disease (BCWD). Mechanistic study of disease resistance identified a positive phenotypic correlation between post-challenge survival and spleen somatic-index (SI). Herein, we investigated the hypothesis of a genetic correlation between the two traits influenced by colocalizing QTL. We evaluated the inheritance and calculated the genetic correlation in five year-classes of odd- and even-year breeding lines. A total of 322 pedigreed families (n = 25,369 fish) were measured for disease resistance, and 251 families (n = 5,645 fish) were evaluated for SI. Spleen index was moderately heritable in both even-year (h(2) = 0.56±0.18) and odd-year (h(2) = 0.60±0.15) lines. A significant genetic correlation between SI and BCWD resistance was observed in the even-year line (rg = 0.45±0.20, P = 0.03) but not in the odd-year line (rg = 0.16±0.12, P = 0.19). Complex segregation analyses of the even-year line provided evidence of genes with major effect on SI, and a genome scan of a single family, 2008132, detected three significant QTL on chromosomes Omy19, 16 and 5, in addition to ten suggestive QTL. A separate chromosome scan for disease resistance in family 2008132 identified a significant BCWD QTL on Omy19 that was associated with time to death and percent survival. In family 2008132, Omy19 microsatellite alleles that associated with higher disease resistance also associated with increased spleen size raising the hypothesis that closely linked QTL contribute to the correlation between these traits. To our knowledge, this is the first estimation of spleen size heritability and evidence for genetic linkage with specific disease resistance in a teleost fish.
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Affiliation(s)
- Gregory D. Wiens
- National Center for Cool and Cold Water Aquaculture, Agricultural Research Service, United States Department of Agriculture, Kearneysville, West Virginia, United States of America
| | - Roger L. Vallejo
- National Center for Cool and Cold Water Aquaculture, Agricultural Research Service, United States Department of Agriculture, Kearneysville, West Virginia, United States of America
| | - Timothy D. Leeds
- National Center for Cool and Cold Water Aquaculture, Agricultural Research Service, United States Department of Agriculture, Kearneysville, West Virginia, United States of America
| | - Yniv Palti
- National Center for Cool and Cold Water Aquaculture, Agricultural Research Service, United States Department of Agriculture, Kearneysville, West Virginia, United States of America
| | - Sima Hadidi
- National Center for Cool and Cold Water Aquaculture, Agricultural Research Service, United States Department of Agriculture, Kearneysville, West Virginia, United States of America
| | - Sixin Liu
- National Center for Cool and Cold Water Aquaculture, Agricultural Research Service, United States Department of Agriculture, Kearneysville, West Virginia, United States of America
| | - Jason P. Evenhuis
- National Center for Cool and Cold Water Aquaculture, Agricultural Research Service, United States Department of Agriculture, Kearneysville, West Virginia, United States of America
| | - Timothy J. Welch
- National Center for Cool and Cold Water Aquaculture, Agricultural Research Service, United States Department of Agriculture, Kearneysville, West Virginia, United States of America
| | - Caird E. Rexroad
- National Center for Cool and Cold Water Aquaculture, Agricultural Research Service, United States Department of Agriculture, Kearneysville, West Virginia, United States of America
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Houston RD, Davey JW, Bishop SC, Lowe NR, Mota-Velasco JC, Hamilton A, Guy DR, Tinch AE, Thomson ML, Blaxter ML, Gharbi K, Bron JE, Taggart JB. Characterisation of QTL-linked and genome-wide restriction site-associated DNA (RAD) markers in farmed Atlantic salmon. BMC Genomics 2012; 13:244. [PMID: 22702806 PMCID: PMC3520118 DOI: 10.1186/1471-2164-13-244] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2012] [Accepted: 05/15/2012] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND Restriction site-associated DNA sequencing (RAD-Seq) is a genome complexity reduction technique that facilitates large-scale marker discovery and genotyping by sequencing. Recent applications of RAD-Seq have included linkage and QTL mapping with a particular focus on non-model species. In the current study, we have applied RAD-Seq to two Atlantic salmon families from a commercial breeding program. The offspring from these families were classified into resistant or susceptible based on survival/mortality in an Infectious Pancreatic Necrosis (IPN) challenge experiment, and putative homozygous resistant or susceptible genotype at a major IPN-resistance QTL. From each family, the genomic DNA of the two heterozygous parents and seven offspring of each IPN phenotype and genotype was digested with the SbfI enzyme and sequenced in multiplexed pools. RESULTS Sequence was obtained from approximately 70,000 RAD loci in both families and a filtered set of 6,712 segregating SNPs were identified. Analyses of genome-wide RAD marker segregation patterns in the two families suggested SNP discovery on all 29 Atlantic salmon chromosome pairs, and highlighted the dearth of male recombination. The use of pedigreed samples allowed us to distinguish segregating SNPs from putative paralogous sequence variants resulting from the relatively recent genome duplication of salmonid species. Of the segregating SNPs, 50 were linked to the QTL. A subset of these QTL-linked SNPs were converted to a high-throughput assay and genotyped across large commercial populations of IPNV-challenged salmon fry. Several SNPs showed highly significant linkage and association with resistance to IPN, and population linkage-disequilibrium-based SNP tests for resistance were identified. CONCLUSIONS We used RAD-Seq to successfully identify and characterise high-density genetic markers in pedigreed aquaculture Atlantic salmon. These results underline the effectiveness of RAD-Seq as a tool for rapid and efficient generation of QTL-targeted and genome-wide marker data in a large complex genome, and its possible utility in farmed animal selection programs.
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Affiliation(s)
- Ross D Houston
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Midlothian, EH25 9RG, UK
| | - John W Davey
- Institute of Evolutionary Biology, Ashworth Laboratories, King’s Buildings, University of Edinburgh, Edinburgh, EH9 3JT, UK
| | - Stephen C Bishop
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Midlothian, EH25 9RG, UK
| | - Natalie R Lowe
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Midlothian, EH25 9RG, UK
| | | | - Alastair Hamilton
- Landcatch Natural Selection Ltd., Alloa, Clackmannanshire, FK10 3LP, UK
| | - Derrick R Guy
- Landcatch Natural Selection Ltd., Alloa, Clackmannanshire, FK10 3LP, UK
| | - Alan E Tinch
- Landcatch Natural Selection Ltd., Alloa, Clackmannanshire, FK10 3LP, UK
| | - Marian L Thomson
- Institute of Evolutionary Biology, Ashworth Laboratories, King’s Buildings, University of Edinburgh, Edinburgh, EH9 3JT, UK
- The GenePool Genomics Facility, Ashworth Laboratories, King’s Buildings, University of Edinburgh, Edinburgh, EH9 3JT, UK
| | - Mark L Blaxter
- Institute of Evolutionary Biology, Ashworth Laboratories, King’s Buildings, University of Edinburgh, Edinburgh, EH9 3JT, UK
- The GenePool Genomics Facility, Ashworth Laboratories, King’s Buildings, University of Edinburgh, Edinburgh, EH9 3JT, UK
| | - Karim Gharbi
- Institute of Evolutionary Biology, Ashworth Laboratories, King’s Buildings, University of Edinburgh, Edinburgh, EH9 3JT, UK
- The GenePool Genomics Facility, Ashworth Laboratories, King’s Buildings, University of Edinburgh, Edinburgh, EH9 3JT, UK
| | - James E Bron
- Institute of Aquaculture, University of Stirling, Stirling, FK9 4LA, UK
| | - John B Taggart
- Institute of Aquaculture, University of Stirling, Stirling, FK9 4LA, UK
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15
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Herath TK, Bron JE, Thompson KD, Taggart JB, Adams A, Ireland JH, Richards RH. Transcriptomic analysis of the host response to early stage salmonid alphavirus (SAV-1) infection in Atlantic salmon Salmo salar L. FISH & SHELLFISH IMMUNOLOGY 2012; 32:796-807. [PMID: 22365992 DOI: 10.1016/j.fsi.2012.02.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2011] [Revised: 01/31/2012] [Accepted: 02/01/2012] [Indexed: 05/31/2023]
Abstract
Salmon pancreas disease, caused by salmonid alphavirus (SAV) of the family Togaviridae, is an economically important disease affecting farmed Atlantic salmon (Salmo salar L.) in Scotland, Norway, and Ireland. The virus causes characteristic lesions in the pancreas, heart, kidney and skeletal muscle of infected fish. The mechanisms responsible for the pathology and the immune responses elicited in infected Atlantic salmon are not fully understood. A microarray-based study was therefore performed to evaluate the host transcriptomic response during the early stages of an experimentally-induced SAV-1 infection. Atlantic salmon parr were injected intra-peritoneally with viral cell culture supernatant or cell culture supernatant without virus. RNA, extracted from head kidney sampled from infected and control fish at 1, 3 and 5 days post-injection (d.p.i.), was interrogated with the 17 k TRAITS/SGP cDNA microarray. The greatest number of significantly differentially expressed genes was recorded at 3 d.p.i., mainly associated with immune and defence mechanisms, including genes involved in interferon I pathways and Major Histocompatibility Complex Class I and II responses. Genes associated with apoptosis and cellular stress were also found to be differentially expressed between infected and uninfected individuals, as were genes involved in inhibiting viral attachment and replication. The microarray results were validated by follow-on analysis of eight genes by real-time PCR. The findings of the study reflect mechanisms used by the host to protect itself during the early stages of SAV-1 infection. In particular, there was evidence of rapid induction of interferon-mediated responses similar to those seen during mammalian alphavirus infections, and also early involvement of an adaptive immune response. This study provides essential knowledge to assist in the development of effective control and management strategies for SAV-1 infection.
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Affiliation(s)
- Tharangani K Herath
- Institute of Aquaculture, Faculty of Natural Sciences, University of Stirling, Stirling, UK.
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16
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Verrier ER, Langevin C, Tohry C, Houel A, Ducrocq V, Benmansour A, Quillet E, Boudinot P. Genetic resistance to rhabdovirus infection in teleost fish is paralleled to the derived cell resistance status. PLoS One 2012; 7:e33935. [PMID: 22514610 PMCID: PMC3326022 DOI: 10.1371/journal.pone.0033935] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2011] [Accepted: 02/24/2012] [Indexed: 12/31/2022] Open
Abstract
Genetic factors of resistance and predisposition to viral diseases explain a significant part of the clinical variability observed within host populations. Predisposition to viral diseases has been associated to MHC haplotypes and T cell immunity, but a growing repertoire of innate/intrinsic factors are implicated in the genetic determinism of the host susceptibility to viruses. In a long-term study of the genetics of host resistance to fish rhabdoviruses, we produced a collection of double-haploid rainbow trout clones showing a wide range of susceptibility to Viral Hemorrhagic Septicemia Virus (VHSV) waterborne infection. The susceptibility of fibroblastic cell lines derived from these clonal fish was fully consistent with the susceptibility of the parental fish clones. The mechanisms determining the host resistance therefore did not associate with specific host immunity, but rather with innate or intrinsic factors. One cell line was resistant to rhabdovirus infection due to the combination of an early interferon IFN induction - that was not observed in the susceptible cells - and of yet unknown factors that hamper the first steps of the viral cycle. The implication of IFN was well consistent with the wide range of resistance of this genetic background to VSHV and IHNV, to the birnavirus IPNV and the orthomyxovirus ISAV. Another cell line was even more refractory to the VHSV infection through different antiviral mechanisms. This collection of clonal fish and isogenic cell lines provides an interesting model to analyze the relative contribution of antiviral pathways to the resistance to different viruses.
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Affiliation(s)
- Eloi R. Verrier
- INRA, Molecular Virology and Immunology, Jouy en Josas, France
- INRA, GABI UMR 1313 Animal Genetics and Integrative Biology, Jouy en Josas, France
- AgroParisTech, Paris, France
| | | | - Corinne Tohry
- INRA, Molecular Virology and Immunology, Jouy en Josas, France
| | - Armel Houel
- INRA, Molecular Virology and Immunology, Jouy en Josas, France
| | - Vincent Ducrocq
- INRA, GABI UMR 1313 Animal Genetics and Integrative Biology, Jouy en Josas, France
| | | | - Edwige Quillet
- INRA, GABI UMR 1313 Animal Genetics and Integrative Biology, Jouy en Josas, France
| | - Pierre Boudinot
- INRA, Molecular Virology and Immunology, Jouy en Josas, France
- * E-mail:
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Skjesol A, Skjæveland I, Elnæs M, Timmerhaus G, Fredriksen BN, Jørgensen SM, Krasnov A, Jørgensen JB. IPNV with high and low virulence: host immune responses and viral mutations during infection. Virol J 2011; 8:396. [PMID: 21827718 PMCID: PMC3169513 DOI: 10.1186/1743-422x-8-396] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2011] [Accepted: 08/10/2011] [Indexed: 01/10/2023] Open
Abstract
Background Infectious pancreatic necrosis virus (IPNV) is an aquatic member of the Birnaviridae family that causes widespread disease in salmonids. IPNV is represented by multiple strains with markedly different virulence. Comparison of isolates reveals hyper variable regions (HVR), which are presumably associated with pathogenicity. However little is known about the rates and modes of sequence divergence and molecular mechanisms that determine virulence. Also how the host response may influence IPNV virulence is poorly described. Methods In this study we compared two field isolates of IPNV (NFH-Ar and NFH-El). The sequence changes, replication and mortality were assessed following experimental challenge of Atlantic salmon. Gene expression analyses with qPCR and microarray were applied to examine the immune responses in head kidney. Results Significant differences in mortality were observed between the two isolates, and viral load in the pancreas at 13 days post infection (d p.i.) was more than 4 orders of magnitude greater for NFH-Ar in comparison with NFH-El. Sequence comparison of five viral genes from the IPNV isolates revealed different mutation rates and Ka/Ks ratios. A strong tendency towards non-synonymous mutations was found in the HRV of VP2 and in VP3. All mutations in VP5 produced precocious stop codons. Prior to the challenge, NFH-Ar and NFH-El possessed high and low virulence motifs in VP2, respectively. Nucleotide substitutions were noticed already during passage of viruses in CHSE-214 cells and their accumulation continued in the challenged fish. The sequence changes were notably directed towards low virulence. Co-ordinated activation of anti-viral genes with diverse functions (IFN-a1 and c, sensors - Rig-I, MDA-5, TLR8 and 9, signal transducers - Srk2, MyD88, effectors - Mx, galectin 9, galectin binding protein, antigen presentation - b2-microglobulin) was observed at 13 d p.i. (NFH-Ar) and 29 d p.i. (both isolates). Conclusions Mortality and expression levels of the immune genes were directly related to the rate of viral replication, which was in turn associated with sequences of viral genes. Rapid changes in the viral genome that dramatically reduced virus proliferation might indicate a higher susceptibility to protective mechanism employed by the host. Disease outbreak and mortality depend on a delicate balance between host defence, regulation of signalling cascades and virus genomic properties.
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Affiliation(s)
- Astrid Skjesol
- Norwegian College of Fishery Sciences, University of Tromsø, N- 9037 Tromsø, Norway
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