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ARS Home » Midwest Area » Madison, Wisconsin » Vegetable Crops Research » Research » Research Project #424886

Research Project: Resistance-Determining Interactions Between Phytopathogenic Phytophthora Effector IPI-O and the Host Resistance Protein RB -CFDA #10.310

Location: Vegetable Crops Research

Project Number: 5090-21220-002-14-A
Project Type: Cooperative Agreement

Start Date: Dec 15, 2013
End Date: Nov 1, 2017

The specific objectives of this research are to: 1. Determine the role of effectors in the ability of P. infestans to overcome RB resistance. We hypothesize that the presence of specific effectors rather than the absence of others results in increased virulence in the presence of RB; 2. Characterize the molecular interactions between P. infestans effectors and RB. We hypothesize that binding of certain effector proteins to the coiled coil domain of RB interferes with proper activation of the resistance protein; 3. Identify or engineer RB genes that can resist suppression by P. infestans effectors. We hypothesize that variants of RB that do not interact with effectors are immune to suppression by this effector.

The approach includes a combination of cellular, molecular genetic, and bioinformatic methodologies to elucidate mechanisms involved in the interaction between P. infestans effectors and target host proteins. We will use stable transgenic potato expressing specific P. infestans effectors and RB in pathogen inoculation studies to test whether the presence of some effectors alone is responsible for resistance suppression. We will also use site-directed mutagenesis to identify RB amino acids required for interaction with effectors and abrogation of suppression. Finally, using information from site-directed mutagenesis and/or structure-function analyses, we will use PCR and DNA sequencing to identify RB variants from wild potato species that avoid suppression and, thereby, confer broader spectrum resistance.