Collaborative Research: Arabidopsis 2010: Dissecting Cortical Actin Function during Arabidopsis-Pseudomonas Interactions

Purdue University, West Lafayette IN

Investigators

Abstract

An exquisite and intricate crosstalk exists between bacterial phytopathogens and the host cells and tissues they invade. New information suggests that a dynamic network of filaments, the cytoskeleton, is essential for both resistance and susceptibility to plant pathogens. However, exactly which molecules from the bacterium stimulate cytoskeletal responses, and which plant proteins are necessary for these responses remains poorly understood. In this project, the investigators will dissect the genetic basis for crosstalk between bacterial effector proteins and the plant host cytoskeleton. Using both molecular genetics tools and advanced imaging technologies, the investigators will test the hypothesis that specific pathogen effector proteins perturb plant actin-binding proteins (ABPs), which in turn leads to alterations in the plant cytoskeleton during defense signaling. A toolbox of actin and actin-binding protein mutants will be developed, and a delivery system for introducing bacterial effectors into host cells will be exploited. Through this work, the PIs aim to identify the function of bacterial effector proteins and 39 plant genes/proteins in order to uncover the signaling network. Lead PI Staiger will coordinate activities between the groups and exploit state-of-the-art imaging modalities to evaluate the defects in actin dynamics in the ABP collection and in response to effector proteins. The Day and Chang laboratories will use genetic approaches to dissect whether crosstalk involves pathogen-associated molecular pattern recognition responses (PTI) or effector-triggered immunity (ETI), or both. These two labs will also use a novel bacterial delivery system to associate changes in actin dynamics to a corresponding bacterial effector protein. The two labs will also prepare constructs for protein-protein interaction assays and subcellular localization. All project data and resources created in this work will be disseminated in a timely fashion at a joint website: http://actinpathogen-network.msu.edu. The broader impact of this work will contribute to a deep understanding of host?pathogen signaling and will enable crop modifications to protect against diseases that devastate agricultural productivity. As a unique outreach component, we will establish a summer workshop to train all project scientists and other interested parties, including local high school students, in advanced methods for imaging cellular dynamics.