Interactions between pathogens and individuals of a host species can be either compatible, in which case disease is established, or incompatible, wherein How plants defend themselves against disease is the focus of my research. recognition of the pathogen triggers a rapid and effective resistance response. Although disease ensues in a compatible interaction, the host plant does respond to the presence of the pathogen by activating a plethora of defense mechanisms which limit the extent of disease. To identify both signaling molecules and end products that are effective in restricting disease, and working in collaboration with other researchers, I have characterized several mutants which are more susceptible to the biotrophic fungal pathogen Erysiphe orontii. Identification of the mutated genes is currently underway. Future plans include expression profiling of the mutants through microarray analysis to elucidate the functions of the genes identified.