Broad-Spectrum Mildew Resistance in Arabidopsis thaliana Mediated by RPW8

Abstract
Plant disease resistance (R) genes control the recognition of specific pathogens and activate subsequent defense responses. We show that the Arabidopsis thaliana locusRESISTANCE TO POWDERY MILDEW8 (RPW8) contains two naturally polymorphic, dominant R genes, RPW8.1and RPW8.2, which individually control resistance to a broad range of powdery mildew pathogens. Although the predicted RPW8.1 and RPW8.2 proteins are different from the previously characterizedR proteins, they induce localized, salicylic acid–dependent defenses similar to those induced byR genes that control specific resistance. Apparently, broad-spectrum resistance mediated by RPW8 uses the same mechanisms as specific resistance.