Jean T. Greenberg, Ph.D.

Research

My broad interest is in how organisms adapt to a changing environment. I study this in the context of host-pathogen interactions using the model system of the plant Arabidopsis thaliana and the gram negative pathogen Pseudomonas syringae. In response to infection, plants mount a complex defense response involving cell suicide, the crosslinking of cell wall components, antibiotic production and defense gene activation. We discovered that infection also activates cell growth and the cell cycle. We study how Arabidopsis regulates its defense and cell death response to pathogens using mutants, which express one or more aspects of the defense response in the absence of pathogens. We focus on a particular class of mutants, which show cell suicide and defense responses when no pathogen is present. We call these mutants acd for accelerated cell death. We are also studying virulence proteins secreted by pathogenic bacteria by a specialized type III secretion system directly into plant cells. We do structure-function analysis on known secreted proteins (called effectors) to determine how they function to exert their virulence, we study the role of effectors in host range restriction and we study the localization and host targets of effectors.