STRUCTURE OF THE ARABIDOPSIS RPM1 GENE ENABLING DUAL-SPECIFICITY DISEASE RESISTANCE

Plants can recognize pathogens through the action of disease resistanc e (R) genes, which confer resistance to pathogens expressing unique co rresponding avirulence (avr) genes. The molecular basis of this gene-f or-gene specificity is unknown. The Arabidopsis thaliana RPM1 gene ena bles dual specificity to pathogens expressing either of two unrelated Pseudomonas syringae avr genes. Despite this function, RPM1 encodes a protein sharing molecular features with recently described single-spec ificity R genes. Surprisingly, RPM1 is lacking from naturally occurrin g, disease-susceptible Arabidopsis accessions.