Plant & Animal Genomes XI Conference

January 11-15, 2003
Town & Country Convention Center
San Diego, CA

Workshop: Barley
            

USING EST DATABASES TO EXAMINE BARLEY-PATHOGEN INTERACTIONS

Department of Agronomy and Plant Genetics, University of Minnesota, St. Paul, MN 55108 USA

Expressed sequence tag (EST) databases offer an excellent resource to study barley-pathogen interactions. Large EST datasets have been developed from barley and wheat infected with Fusarium graminearum (Fg) and barley infected with Blumeria graminis f.sp. hordei (Bgh). From approximately 20,000 barley and 5,000 wheat ESTs, we derived 8,400 nonredundant sequences (unigenes) for barley and 3,552 unigenes for wheat. Functional annotations for each unigene were derived from BLASTX hits to the non-redundant protein database in Genbank. Genes encoding structural, metabolic and stress-related proteins were amongst the most abundantly expressed in response to Fg and Bgh infection. We used these datasets to identify 863 barley genes that were expressed in wheat and barley in response to Fg infection, of which 16 appear to be specific to Fg infection. We also used these datasets to identify 982 barley genes expressed in response to Fg and Bgh infection, of which 17 appear to be expressed specifically in barley-Fg and Bgh interactions. In addition, we identified 70 genes specifically expressed in at least two plant-microbe interactions. Our analysis indicates that all plant-microbe interactions have a common set of rarely expressed genes. These datasets also provided insight into the fungal genes that are potential pathogenesis and virulence factors. 143 Fg and Bgh genes appear to be specific to infection and are potentially pathogenesis-related genes. A subset of 13 fungal genes did not have homologs in Saccharomyces cerevisiae and Neurospora crassa and may represent fungal virulence factors.