2004 Annual Report 1.What major problem or issue is being resolved and how are you resolving it (summarize project aims and objectives)? How serious is the problem? What does it matter? Fungal pathogens are perhaps the greatest impediment to production of grain cereal plants worldwide. When environmental conditions are opportune for pathogen growth, between 30 and 50% of potential yield can be lost. To offset crop losses from pathogens, plant breeders have turned to genetic varieties that help crops resist these diseases. While the Arabidopsis genome [120 million letters of genetic code] is the smallest in plants, it has been more difficult to isolate genes from crops that possess genomes even larger than humans. For example, the barley and wheat genomes are 40 and 130 times larger than Arabidopsis, and until recently, this size difference has hindered research on the mechanisms underlying resistance to devastating diseases. Thus, in small grain Triticeae crops, the molecular characterization of genes coincident with disease, response to biotic or abiotic stresses, or cellular development has traditionally followed a "one-gene-at-a-time" approach. However, recent advances in microarray technology now allow the study of thousands of genes in a single experiment. Instead of checking genes individually in smaller scale experiments, the genes of an entire organism can be studied simultaneously. We have initiated microarray expression studies targeted at recognition and active defense against fungal diseases in small grain cereal crops. This fundamental knowledge is critical to our utilization of genetic resistance to control plant diseases in cereal crops, and for the U.S. to remain competitive in cereal-grain production. We are using barley powdery mildew as our initial model system. The disease is caused by the obligate fungal pathogen, Blumeria graminis, and is widely distributed throughout the world. It is most damaging in cool, wet climates such as Northern Europe and the winter growing season in the Mid-Atlantic and Southeastern U.S. Powdery mildew disease causes reduced grain yield, kernel weight and grain protein. Excellent genetic materials and availability of cloned genes specifying resistance to this disease make this system ideal for basic studies relating to recognition and active defense [see CRIS project #3625-21000-035-02T (USDA-NRI/CGP 00-35300-9213)]. How does it relate to the National Program(s) and National Program Component(s)? Host-plant resistance is the most desirable control strategy because it can be highly effective, is environmentally benign, and requires little or no additional expense to producers. This research enables breeders to utilize resistance more effectively. This research addresses NP302, Plant Biological and Molecular Processes. 2.List the milestones (indicators of progress) from your Project Plan. Objective 1 Define the complete primary structure of the Mla (powdery mildew) resistance complex. Utilize the inherent diversity amongst Mla encoded proteins to identify amino acids required for RAR1 disease resistance signaling. Identify genes expressed during fungal disease resistance via microarray technology. Establish function of genes identified through microarray technology. Coordinate Plant Gene Expression Database, an essential and leveraging resource for trait improvement (presently funded by USDA-NRI). 3.Milestones: A. List the milestones that were scheduled to be addressed in FY 2004. How many milestones did you fully or substantially meet in FY 2004 and indicate which ones were not fully or substantially met, briefly explain why not, and your plans to do so. Objective 1 Utilize the inherent diversity amongst Mla encoded proteins to identify amino acids required for RAR1 disease resistance signaling. This milestone has been completed. Identify genes expressed during Mla-mediated disease resistance via microarray technology. Phase 1 of this milestone has been completed; identified link between gene-specific resistance and general (basal) defense to plant disease. Coordinate microarray expression database. Completed initial phases of this NRI-funded project. The URL is http://barleybase.org/ B. List the milestones that you expect to address over the next 3 years (FY 2005, 2006, and 2007). What do you expect to accomplish, year by year, over the next 3 years under each milestone? FY 2005 Objective 1 Identify genes expressed during Mla-mediated disease resistance via microarray technology. These expression-profiling experiments currently yield 500,000 data points per replication, and thus, provide the exhaustive foundation necessary to understand the molecular mechanisms underlying resistance responses to fungal infection. The research is of high impact because plant diseases are among the greatest impediments to crop production worldwide. Thus, new knowledge of the basic mechanisms of disease resistance will provide breeders with better tools, resulting in less damage to crops, therefore, increasing sustainability and profitability. Coordinate Plant Gene Expression Database (presently funded by USDA-NRI). A National plant gene expression database will integrate new and rapidly expanding expression profile data sets with traditional structural and phenotypic data, thus providing the information resource for trait improvement at the desktop. FY 2006 Objective 1 Identify genes expressed during Mla-mediated disease resistance via microarray technology. Establish function of genes identified through microarray technology. Coordinate Plant Gene Expression Database, an essential and leveraging resource for trait improvement. FY 2007 Objective 1 Identify genes expressed during Mla-mediated disease resistance via microarray technology. Establish function of genes identified through microarray technology. Coordinate Plant Gene Expression Database, an essential and leveraging resource for trait improvement. 4.What were the most significant accomplishments this past year? D. Progress Report. This report serves to document research conducted under a specific cooperative agreement between ARS and Iowa State University. Additional details of research can be found in the report for the parent project #3625-21000-035-00D, Cereal Genomics and Pathology. Homologs of barley genes induced during powdery mildew resistance responses were identified in dicot model organisms, Arabidopsis thaliana, tomato, and Nicotiana benthamiana. This will allow the function of these barley genes to be studied in resistance responses in both monocot and dicot plant species. The Wise laboratory provided sequences of barley genes induced during powdery mildew resistance responses to the Whitham laboratory at Iowa State University. The sequences of the barley genes were used to identify homologs from the dicot plant species and experiments were initiated to knock-down or knock-out functions of these genes in Arabidopsis thaliana and Nicotiana benthamiana. We expect these studies will contribute to more complete understanding of general plant resistance mechanisms and lead to enhanced protection of crop plants against plant pathogens. 5.Describe the major accomplishments over the life of the project, including their predicted or actual impact. The overall theme for this project has been to characterize genetic and cellular functions in plant-pathogen interactions. This project is in its first year.