Page Banner

United States Department of Agriculture

Agricultural Research Service

Related Topics

Research Project: PRRS CAP HOST GENETICS: CHARACTERIZATION OF HOST FACTORS THAT CONTRIBUTE TO PRRS DISEASE RESISTANCE AND SUSCEPTIBILITY

Location: Animal Parasitic Diseases

2010 Annual Report


1a.Objectives (from AD-416)
Continued losses to the pig industry from porcine reproductive and respiratory syndrome (PRRS) make it imperative to search for alternative PRRS control practices. This grant proposes to use state-of-the-art whole genome association analyses to identify the genetic determinants of resistance/susceptibility of commercial U.S. swine to PRRSV infection. We will address PRRS coordinated agricultural project (CAP2) Objective 3: Characterize host factors that contribute to PRRS disease resistance and susceptibility (host genetics). The primary samples to be tested will be those collected through the NPB funded PRRS Host Genomic Consortium (PHGC), a national effort to collect phenotypic data to assess the role of genetics in determining pig resistance to PRRSV infection and related pathology and growth effects. DNA samples from PHGC pigs will be genotyped with the newly developed 60K single nucleotide polymorphism (SNP) chips. Obj.3.1. Addresses research on immunity and vaccination using gene expression analyses to reveal new PRRS response pathways that can be targeted for vaccines, drugs and biotherapeutics to prevent and treat PRRSV infections. Obj.3.2. Will use whole genome association studies to reveal new genetic alleles associated with PRRS resistance/susceptibility. The extensive genomic (SNP) analyses will find allele variants that determine resistance/susceptibility of commercial U.S. swine to PRRSV infection.


1b.Approach (from AD-416)
Extensive whole-genome association analyses will be performed to determine which markers are associated with PRRS susceptibility/ resistance traits. Simultaneously gene expression analyses are planned to determine PRRS response pathways and critical candidate genes that differ in expression between PRRS resistant versus susceptible PHGC pigs and to dissect pathologic versus protective immune responses in samples collected from PRRSV infected versus vaccinated swine. Overall the proposed studies will identify genetic determinants of resistance/susceptibility of commercial U.S. swine to PRRSV infection. This information will be disseminated to swine breeders, genetics companies and genotyping services so that sets of these recommended genetic markers can be employed in future breeding programs to increase disease resistance.


3.Progress Report

For this Agreement, studies were initiated to identify genetic determinants of resistance/susceptibility of commercial U.S. swine to Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) infection. State-of-the-art whole genome association analyses to identify the genetic determinants of resistance/susceptibility of commercial U.S. swine to PRRSV infection have been started by a team led by ARS Researchers at Beltsville, MD and including scientists from Iowa State, Washington State, Purdue, and Michigan State Universities. The primary samples tested are those collected through the National Pork Board funded PRRS Host Genomic Consortium (PHGC), a national effort to collect phenotypic data to assess the role of genetics in determining pig resistance to PRRSV infection and related pathology and growth effects [presented in 1265-32000-088-11R report.] DNA samples from pigs from six PHGC trials 1-6 and their parents (1300 DNAs total) were prepared at by ARS Researchers at Beltsville, MD and were genotyped with the 60K single nucleotide polymorphism (SNP) chip, the Porcine SNP60 BeadChip. Extensive whole-genome association analyses are now underway at Iowa State to determine which markers are associated with PRRS susceptibility/ resistance traits and related pathology and growth effects. This information will be disseminated to swine breeders, genetics companies and genotyping services so that sets of these recommended genetic markers can be employed in future breeding programs to increase disease resistance. Comparative mucosal anti-PRRSV gene expression studies are dissecting pathologic versus protective responses. Gene expression studies of tissues from PRRSV infected and/or vaccinated pigs have examined critical timepoints in the anti-PRRSV respiratory responses, and compared pathologic versus protective responses after challenge of vaccinated pigs with homologous versus heterologous virus. Mucosal tissue samples from PRRSV infected and/or vaccinated pigs were collected at North Carolina State University. Tissue RNA were prepared and then amplified, labeled by ARS Researchers at Beltsville, MD for comparative hybridization using swine long oligo microarrays, Pigoligoarrays, containing ~20,000 positive and 60 negative control probes, and a loop design developed by Michigan State University collaborators. Extensive gene expression data from more than 80 arrays is now being analyzed by ARS Researchers at Beltsville, MD using Ingenuity pathway software. Additionally tissue RNAs have been sent to Purdue for targeted gene expression work, e.g., cell-mediated immunity, known PRRSV receptors. These studies are expected to reveal new PRRS response pathways that can be targeted for vaccines, drugs and biotherapeutics to prevent and treat PRRSV infections.

Disseminating progress on this grant is through regular email and phone contact with the participating labs discussing project plans and presentation options. A consortium meeting was held 1/9/10 as part of Plant and Animal genome meetings in San Diego, CA. Progress was presented by ISU and MSU collaborators at the 6/6/10 PRRS CAP annual meeting.


Last Modified: 7/22/2014
Footer Content Back to Top of Page