Location: Cereal Crops Research
Title: Progress Toward Map-Based Cloning of an Avirulence Gene from Pyrenophora teres f. teres Authors
Submitted to: International Congress of Plant Pathology Abstracts and Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: November 15, 2007
Publication Date: August 24, 2008
Citation: Liu, Z., Faris, J.D., Edwards, M.C., Friesen, T.L. 2008. Progress Toward Map-Based Cloning of an Avirulence Gene from Pyrenophora teres f. teres. International Congress of Plant Pathology Abstracts and Proceedings. 90(S2):229 Technical Abstract: The fungus Pyrenophora teres is a worldwide and economically important pathogen of barley, causing barley net blotch. A gene-for-gene relationship has been characterized in this host-pathogen system and four avirulence/virulence genes have been identified and mapped in the fungus. Here, our goal is to isolate AvrHar, the first Avr gene identified and mapped in P. teres, using a map-based approach. Chromosome walking was initiated from an AFLP marker 2.2 cM from AvrHar using a 178-progeny fungal mapping population. Genotypic and phenotypic analysis has led to the construction of a 300 kb contig, which includes one fosmid and three BACs, within the AvrHar genomic region. A PCR-based marker located at the end of the contig co-segregates with AvrHar. We have completely sequenced 250 kb of the contig, which consists of a large amount of repetitive DNA and 40 predicted genes. Interestingly, some of the repeat sequence has similarity to that surrounding AvrLm1, an Avr gene in Leptosphaeria maculans. The gene-coding region was shown to have high co-linearity to chromosome 2 of P. tritici-repentis, a related pathogen that causes tan spot of wheat. Recently initiated shotgun sequencing of another BAC clone, spanning an additional 70 kb in the direction of AvrHar, could potentially allow us to delineate the AvrHar candidate region.