The suite of pathogenicity factors in Pseudomonas syringae

Our goal is to understand how bacterial pathogens cause disease on their hosts. We are working with a plant pathogen, Pseudomonas syringae. Like many bacterial pathogens of both animals and plants P. syringae transfers pathogenicity factors into host cells via a specialized secretion structure called the Type III secretion system. The transferred pathogenicity factors are called Type III effectors because they are the effectors of disease. Comparison of over 50 P. syringae Type III effectors has not indicated that they have common functions. In fact, they share little sequence homology to each other or to proteins of known function from other organisms. Instead, they may perform a variety of functions, presumably acting on diverse plant targets. The goal of our research is to use functional and genomic approaches to identify as many of the P. syringae Type III effectors as possible. At the same time we are characterizing a chosen set of individual type III effectors in order to discover how each effector interacts with its host to cause disease. We are currently developing tools to assay the effector-host interaction in collaboration with Jeffery Dangl's lab in the Department of Biology, UNC-CH.