|Reddy, Leela - PLNT SCI, NDSU, FARGO ND|
|Meinhardt, Steven - CHEM DEPT, NDSU, FARGO ND|
Submitted to: Plant and Animal Genome VX Conference Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: October 30, 2005
Publication Date: January 5, 2006
Citation: Reddy, L., Friesen, T.L., Meinhardt, S.W., Faris, J.D. 2006. High-resolution mapping and chromosome walking at the snn1 locus on chromosome 1b in wheat [abstract]. Plant and Animal Genome XIV Conference. Abstract No. P349:188. Technical Abstract: Better understanding of host-pathogen interactions at the molecular level requires isolation and characterization of genes from both host and pathogen. In previous research, we identified a host-selective proteinaceous toxin (SnTox1) produced by the fungus Stagonospora nodorum (Berk). A single dominant gene (Snn1) conferring sensitivity to SnTox1 in wheat was identified, and the gene was mapped within a major gene-rich region of the short arm of chromosome 1B. We are currently using a map-based cloning approach in an effort to isolate Snn1. Saturation mapping of Snn1 was conducted using RFLP, SSR, EST, and STS markers in a segregating population of 120 F2 plants. Markers tightly linked to Snn1 were resolved by mapping in a large population consisting of 1,025 insensitive F¬2 plants, and Snn1 was delineated to a 0.9 cM interval. The Langdon (LDN) durum BAC library was used to assemble a contig consisting of three BACs spanning about 310 kb at the Snn1 locus. Sequence analysis of the contig indicated that gene-density and recombination frequency are highly variable in this region. At least six putative genes cosegregate with Snn1and are considered potential candidates. Work to confirm that the contig spans Snn1 and validation of possible candidate genes is in progress.