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United States Department of Agriculture

Agricultural Research Service

Title: Physical Mapping and Characterization of Yacs Derived from the Mla Resistance Gene Region in Barley

item Morroll, Shaun
item Gobelman Werner, Karin
item Leister, Dario - SAINSBURY LABORATORY
item Kurth, Joachim - SAINSBURY LABORATORY
item Schulze-Lefert, Paul - SAINSBURY LABORATORY
item Wise, Roger

Submitted to: Plant and Animal Genome Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: November 18, 1998
Publication Date: N/A

Technical Abstract: Powdery mildew of barley is a model system for the investigation into the mechanisms of gene-for-gene interaction between large-genome cereals and obligate fungal pathogens. Barley contains a large number of genes, designated <i>Ml, that confer resistance to the powdery mildew fungus, <i>Erysiphe graminis f. sp.<i>hordei. One particular group, the <i>Mla resistance gene cluster, is located on chromosome 5(1H) and is flanked by RFLP markers <i>XciwS10 and <i>Xbcd249.1. We have used AFLP and RAPD technology in conjunction with bulk segregant analysis to identify additional markers and saturate the <i>XciwS10-Xbcd249.1 interval. We identified 7 AFLP and 2 RAPD polymorphisms that were closely linked to the <i>Mla cluster. Two were determined as being 0.09 and 0.12 cM from <i>Mla. Their respective amplified fragments were used to develop allele-specific primers and a total of eleven YACs were identified from screening two independent YAC libraries. A physical contig map of the region spanned by these clones was generated and efforts are underway to determine if this region extends across the <i>Mla locus. Sub-genomic-PCR has been employed to further characterize the YACs with regard to resistance gene analogues (RGAs). This technique was used in conjunction with primers designed from previously isolated resistance genes to selectively amplify homologous sequences from the <i>Mla region contained within selected YACs. This increases the specificity of amplification of RGAs and leads to the possibility of cloning the <i>Mla gene by this PCR strategy.

Last Modified: 4/19/2015