ARS | Publication request: AFLP MAPPING OF THE PCA CROWN-RUST RESISTANCE-GENE CLUSTER IN DIPLOID

Submitted to: Plant and Animal Genome VX Conference Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: December 11, 1996
Publication Date: N/A

Technical Abstract: Puccinia coronata is one of the most important fungal pathogens of cultivated oat. The Pca locus in diploid Avena confers resistance to at least nine isolates of P. coronata, five of these isolates detect individual specificities within the Pca cluster. An independent gene, Su, was found to dominantly suppress the expression of one resistance specificity at the Pca locus. The molecular characterization of this resistance gene cluster and the suppressor will provide evidence to demonstrate; 1) how these genes provide unique specificities to multiple isolates of pathogens, and 2) how the resistance genes are regulated by other related genes such as suppressor genes. We are utilizing AFLP combined with bulked segregant analysis to construct a high resolution map around the Pca and Su loci. A recombinant inbred population of diploid Avena was generated previously by crossing A. strigosa (C.I. 3815) with A. wiestii (C.I. 1994). The A. strigosa parent is resistant to 40 isolates o crown rust in the ISU collection whereas the A. wiestii parent is susceptible to the same isolates. EcoRI and MseI AFLP primer pairs were used to amplify DNA from the two diploid Avena parents and bulks targeting the Pca and Su loci. Of 2,600 amplified fragments, 337 polymorphisms were identified. Of these, two AFLP loci were closely-linked with Pca and two were loosely-linked with Su. The AFLP markers in the Pca and Su regions and their utilization in genetic analysis and gene isolation will be presented.