9303929 Low One of the most rapid defense responses of a plant to an invading pathogen is the oxidative burst, where, within 5 minutes of the encounter of the plant cell with a pathogen-derived elicitor molecule there is the sudden release of hydrogen peroxide and other oxidative species. The oxidative burst is possibly the plant's first line of defense against infection, and appears to result from one of the simplest and most topologically localized signal transduction pathways. The overall goal of this research is to identify and characterize the second messengers and signaling intermediates that communicate the association of an elicitor molecule with its cell surface receptor to the oxidase complex that produces oxygen radicals and hydrogen peroxide. Intermediate goals are to: 1) identify purified elicitors that activate the oxidative burst pathway without stimulating other signaling pathways that lead to delocalized defense responses (e.g. production of phytoalexins or PR proteins), 2) identify second messengers that are activated by such elicitors, 3) rank the second messengers chronologically in order of their appearance, and 4) show linkage or connectivity between adjacent pairs of identified second messengers using messenger-specific inhibitors, activators, etc. %%% One of the most rapid defense responses of a plant cell to an invading pathogen is the "oxidative burst," the sudden release of hydrogen peroxide and other oxidative chemical species. The oxidative burst probably represents the first line of a plant's defense against infection. The goal of this research is to work out the chain of biochemical events between the detection of a pathogen, as signaled by the arrival of a pathogen-specific chemical on a specific plant cell receptor, through the resulting signal transduction pathways, to the production of oxidative chemicals. The results of this research will contribute substantially to our understanding of this important cellular signa ling pathway in plants and should provide considerable information on where and how the defense responses of plants can be genetically manipulated. ***
