Poster: Plant-pathogen interactions

Abs # 560: Structure-Function Studies of Rx, an NBS-LRR-Class Resistance Protein

Presenter:	Rairdan, Greg J, gjr4@cornell.edu
Authors	Rairdan, Greg J (A)   Moffett, Peter  (A)
Affiliations:	(A): Boyce Thompson Institute

Gene-for-gene resistance is an important component of plant defense against potential pathogens. Gene-for-gene resistance is in part mediated by the products of Resistance (R) genes, which are able to recognize specific pathogen-derived molecules and initiate a signal transduction cascade that often leads to hypersensitive cell death and resistance to the perceived pathogen. These R genes often encode proteins with predicted coiled-coil (CC) domains, nucleotide binding sites (NBS), and leucine-rich repeats (LRRs). Rx is an NBS-LRR-encoding R gene that was isolated from potato, and is capable of recognizing the coat protein (CP) of Potato Virus X (PVX) in potato and other solanaceous species, including Nicotiana sp. Recent data has demonstrated that the various domains of Rx mediate intramolecular interactions that are disrupted in the presence of PVX CP. The ability of these domains to interact and disassociate is closely correlated with the ability of Rx to initiate a hypersensitive response. We are interested in defining the motifs of Rx that are important for these interactions, and how these interactions relate to the activation of a signaling cascade. We are pursuing large-scale structure-function studies with synthetic mutants that are tested for alterations in their ability to undergo interdomain protein-protein interactions. The purpose of these studies is to define protein-protein interaction domains within the Rx protein as well as identifying other parts of the protein required for activation and signaling. Recent progress will be presented.