Objective:
The long term goal of this project is to reduce losses in wheat and barley yield and quality caused by stripe, leaf, and stem rusts, and assure stable,sustainable wheat and barley production while protecting the environment. Over the next five years we will focus on the following objectives: 1)determine factors influencing epidemic development and host-pathogen interactions for rusts, including to identify and monitor emerging races of stripe rust on a national basis and to improve rust prediction and integrated control; 2)evaluate germplasm and breeding lines of wheat and barley for resistance to rusts,including to support breeding programs in developing cultivars with adequate and durable resistance and to identify new sources and genes of effective resistance to stripe rust; and 3)determine the genomic structure and functional genes of the stripe rust pathogen and molecular mechanisms of plant-pathogen interactions.

Approach:
The prevalence, severity, and distribution of rusts will be monitored through disease surveys in commercial fields, monitoring nurseries, and experimental plots of wheat and barley, as well as wild grasses. Stripe rust races will be identified by testing rust samples on wheat and barley differential genotypes. Rust epidemics will be predicted based on environmental and cropping system factors. Geographic regions where stripe rust can over-winter and over-summer will be mapped by analyzing climatic and cropping data. Disease forecasting models will be developed for various epidemic regions by analyzing historical weather and disease data and tested with rust survey data. Fungicide tests will be conducted to identify new effective fungicides. Germplasms and breeding lines of wheat and barley will be evaluated in greenhouses with selected races and in field plots under natural infections of rusts to support breeding programs. New sources and genes of effective resistance to stripe rust will be identified through germplasm evaluation, genetic studies, and molecular mapping. Molecular markers for resistance genes will be developed using resistance gene analog, microsatellite, and other marker techniques. The genomic structure and functional genes of the stripe rust pathogen and molecular mechanisms of plant-pathogen interactions will be determined through constructing physical and functional gene maps. Fingerprinting and end-sequencing bacterial artificial chromosome (BAC) clones will be conducted to construct the physical map, which will be filled with functional genes identified from cDNA clones of the pathogen. Functional genes will be identified by comparing the sequences of full-length cDNA clones to genes in GenBank databases. Molecular markers will be developed using sequences of functional genes and BAC-ends for studying population structures of the stripe rust pathogen. Genes of wheat and the stripe rust pathogen involved in the plant-pathogen interactions will be identified. Formerly 5348-22000-010-00D (3/07).