This project will investigate the role of active oxygen in restricting pathogenesis by the plant pathogenic bacterium Pseudomonas syringae. The hypothesis that the pathogenic Pseudomonads are able to reduce plant-imposed oxidative stress during pathogenesis though an arsenal of catalase isozymes will be tested. There are two portions to the project: 1) cloning of the genes for the catalase isozymes and construction of mutants for virulence studies; and 2) determination of the interactions of the various catalase genes with the hrp genes that appear to control the pathogenicity of the bacterium. The genetic part will be carried out by Dr. Hutcheson at the University of Maryland, while biochemical and physiological studies will be carried out by Dr. Klotz at Utah State University under another award. %%% This research will contribute to the understanding of the initial events that occur during plant-microbe interactions, and should provide new information on the fundamental differences between microbes that causes plant disease and those which cannot.
