Mechanisms of Bacterial Toxin Plant Membrane Interactions: Studies on the mode of action of the Pseudomonas syringae pv syringae phytotoxin, syringomycin, on plant cell membranes are proposed. Previous studies have shown that syringomycin has a primary effect on the plasma membrane of susceptible cells. Experiments are described for determining the role of protein phosphorylation in the syringomycin stimulation of the plant plasma membrane H+-ATPase, for determining if plasma membrane phosphatidylinositol turnover is involved in toxin action, and for identifying the syringomycin molecular binding site. This project is significant because it will elucidate how a ubiquitous and important bacterial phytotoxin causes plant disease and also because it will provide basic information about the function, structure and regulation of the plant cell plasma membrane.
