Microorganisms that cause plant diseases present a substantial burden to agriculture through yield losses due to plant stress, costs associated with disease control, and efforts to detect infections and limit disease epidemics. Plant breeders are interested in the identification and incorporation of simply inherited genes that confer robust resistance to diseases. These resistance (R) genes typically encode proteins that recognize the presence of very specific pathogen molecules, termed effectors, resulting in the activation of defense responses. However, certain effectors can directly suppress R proteins to allow the pathogen  to elude recognition and cause disease. Using the potato late blight pathosystem, we previously identified a Phytophthora infestans effector that can suppress RB activity through direct interaction with the resistance protein. By mining natural genetic variation of RB from wild potato relatives, we identified specific amino acids within the coiled-coil region of the R protein that allow it to avoid suppression and maintain its ability to activate defense responses in both transient and stable transgenic expression systems.