2006 Annual Report 4d.Progress report. This report serves to document research conducted under a specific cooperative agreement between ARS and Kansas State University, Department of Plant Pathology. Additional details of this research can be found in the report for the parent project 5430-21000-005-00D of the Plant Science and Entomology Research Unit. This is a new project for FY2006. The objectives of this research project are:. 1)Construct genetic populations of wheat for validation of molecular markers for Karnal bunt resistance genes;. 2)Conduct functional analysis of genes up-regulated by rust resistance gene Lr34/Yr18 in wheat;. 3)Determine role of pheromones on germination of Fusarium graminearum. Two putative KB resistance genes have been proposed for marker assisted breeding. The objectives are to verify the effect of these genes. We have F4 seed from individual F2 plants that carried markers for one or both genes. These materials are being used to develop near isogenic lines for the resistance genes. Wheat leaf rust is one of the most important diseases of wheat worldwide. There are two groups of resistance mechanisms that have been described: hypersensitive resistance and slow rusting resistance. Gene expression in two pairs of isolines carry the slow rusting gene, Lr34, was studied using microarray chips. Gene expression patterns suggested a novel mechanism for the slow rusting phenotype. Fusarium graminearum is the major cause of Fusarium head blight of wheat and barley. In previous research, we found that the fungus produces sex pheromones that can affect sexual fertility and germination of spores. This system is being studied for possible control strategies.