Location: Animal Parasitic Diseases Laboratory2011 Annual Report
1a. Objectives (from AD-416)
The specific objectives will be 1) Identify differentially expressed (DE) genes in blood in response to PRRSV infection; 2) Determine putative gene sets and pathways that predict a pig’s ability to clear PRRSV infection and maintain weight gain; and 3) Validate utility of gene sets and pathways for prediction of responsiveness to PRRSV infections in multiple populations.
1b. Approach (from AD-416)
The proposed studies will identify functional genomic determinants, and potential “classifier genes” that predict resistance/susceptibility of commercial U.S. swine to PRRSV infection and associated growth losses. Such gene-specific information will directly complement the genetic variation and QTL mapping data being developed in the PHGC, to provide an integrated view of the molecular genetic architecture of PRRSV resistance. All information will be disseminated to swine researchers and breeders, as well as genetics companies and genotyping services so that these recommended genes can be targeted in future breeding programs to increase resistance to PRRS, the most economically important disease affecting the U.S. pork industry.
3. Progress Report
This agreement covers functional genomic analyses aimed at determining response pathways that differ in porcine respiratory and the reproductive syndrome (PRRS) resistant versus susceptible pigs using samples collected as part of the PRRS Host Genetics Consortium (PHGC). ARS Researchers at Beltsville, MD have partnered with Michigan State University (MSU), Iowa State University (ISU), Washington State University and Purdue University scientists to use PHGC samples to assess whole blood gene expression responses. To date 72 microarrays have been completed with blood RNA samples from 12 pigs collected at 0, 4, 7, 11, 14, 28, 42 days post infection to identify genes and pathways that are associated with pigs that clear PRRS virus (PRRSV) and that grow well despite PRRSV infection. Biostatistical and bioinformatic analyses are now underway at MSU to determine which genes are correlated with viral load and/or weight gain comparing the most desirable, PRRS resistant low virus/high weight gain pigs with the worst, PRRS susceptible high virus/ low weight gain pigs, and the PRRS tolerant, high virus/high weight gain pigs. As this work progresses we expect to develop predictive gene expression pathways and classifier genes that identify pigs which resist PRRSV infection and grow normally. (NP103 2c) This project was monitored through regular email and phone contact, scheduled conference calls, and a yearly Consortium meeting with the participating labs discussing project plans, experimental design, and reviewing data and presentation options.