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Title: Genetic characterization and targeted mapping of a Triticum timopheevii-dervied powdery mildew resistance gene

item Marshall, David
item Brown-Guedira, Gina

Submitted to: Plant and Animal Genome Conference
Publication Type: Abstract Only
Publication Acceptance Date: 1/15/2007
Publication Date: 1/15/2007
Citation: Perugini, L., Murphy, P.J., Marshall, D.S., Brown Guedira, G.L. 2007. Genetic characterization and targeted mapping of a Triticum timopheevii-dervied powdery mildew resistance gene. Plant and Animal Genome Conference.

Interpretive Summary: none

Technical Abstract: There are five alleles conferring race-specific resistance to powdery mildew (caused by Blumeria graminis f. sp. tritici) at the Pm1 locus on the long arm of chromosome 7A of wheat (Triticum aestivum. L). A dominant powdery mildew resistance gene transferred to the hexaploid germplasm line NC99BGTAG11 (AG11) from T. timopheevii subsp. armeniacum was previously identified and mapped distally on 7AL. Differential reactions were observed between the gene in AG11 and the alleles of the Pm1 locus when inoculated with 14 powdery mildew isolates. Allelism tests of 200 F2:3 families involving the tested AG11 resistant line crossed with Axminster (Pm1a) indicated that the AG11 resistance is not an allele of the Pm1 locus, but rather a new locus. The distal region of the wheat chromosome arm 7AL is syntenic to rice chromosome 6 and was targeted for marker enrichment. The order of wheat expressed sequence tags (ESTs) located in the distal 14% of the chromosome arm was determined on the basis of the orthologous rice sequences of chromosome 6 of rice using the BLASTn program. Selected wheat ESTs with high levels of homology to sequences from chromosome 6 of rice were used to design primers for sequence-tagged site (STS) markers and were mapped physically and genetically. In addition, sequences from rice bacterial artificial chromosome clones covering the targeted syntenic region were used to identify additional wheat ESTs in the region. Polymorphic markers will be mapped in the high resolution mapping population to develop a fine structure map of the region.