2007 Annual Report 1a.Objectives (from AD-416) 1. Construct genetic populations of wheat for discovery of molecular markers for wheat resistance genes. 2. Conduct lipidomics analysis of genes up-regulated by rust resistance gene Lr34/Yr18 in wheat. 3. Test feasibility of using pheromones to control Fusarium graminearum on wheat. 1b.Approach (from AD-416) A collaborative program will be conducted to tag and identify genes that control avirulence in the wheat leaf rust fungus. Biolistics will be used to tag genes within the leaf rust fungus genome and sequencing will be used to identify candidate avirulence genes. Resistance genes for important wheat diseases will be genetically mapped and markers will be developed for marker-assisted selection. Microsatellites, amplified fragment length polymorphisms, and expressed sequenced tags will be used as sources of molecular markers. Physical maps will be constructed using genomic libraries and electrophoresis. 3.Progress Report This report serves to document research conducted under a specific cooperative agreement between ARS and Kansas State University, the Department of Plant Pathology. Additional details of this research can be found in the report for the parent project 5430-21000-005-00D, Genetic Enhancement for Resistanct to Biotic and Abiotic Stresses in Hard Winter Wheat. Leaf rust is a major disease of wheat that is economically important worldwide. Molecular markers were identified that flanked the wheat resistance gene Lr17a. These markers allow us to rapidly identify experimental lines that may carry Lr17a, which is thought to be common in hard winter wheat cultivars. Another approach is being used to investigate the process by which the wheat leaf rust pathogen, Puccinia triticina, infects and triggers the resistance pathway. Haustoria are the fungal structures that penetrate wheat leaf cells and withdraw nutrients. Five thousand clones of expressed genes from fungal haustoria were sequenced. These are being evaluated as potential avirulence factors that may trigger the plant defense system. The Lr34/Yr18 wheat resistance gene provides durable, adult-plant, slow-rusting resistance to leaf rust and yellow rust (stripe rust) of wheat. Patterns of gene expression were examined by microarray analysis in two pairs of wheat lines with or without Lr34/Yr18. Many genes with up-regulated expression in Lr34/Yr18 lines are associated with osmotic stress, cold stress, or seed maturation. These results support the hypothesis that Lr34/Yr18 has a novel mode of action. Several of these up-regulated genes could be useful as biomarkers for the presence of the Lr34/Yr18 gene in wheat lines. Progress on this agreement is monitored by regularly discussing program goals and approaches and by reviewing annual accomplishments reports.