lsolation of Arabidopsis Genes That Differentiate between Resistance Responses Mediated by the RPS2 and RPM7 Disease Resistance Genes

The Arabidopsis disease resistance gene RPSP is involved in recognition of bacterial pathogens carrying the avirulence gene avrRpt2, and the RPMl resistance gene is involved in recognition of pathogens carrying avrRpml or avrB. We identified and cloned two Arabidopsis genes, AIGl and AIG2 (for a_vrRpt2-~nduced gene), that exhibit RPSPand avrFfptbdependent induction early after infection with Pseudomonas syringae pv maculicola strain ES4326 carrying avrRpt2. However, ES4326 carrying avrRpml or avrB did not induce early expression of AIGl and AIG2. Conversely, ES4326 carrying avrRpml or avrB induced early expression of the previously isolated defense-related gene ELI3, whereas ES4326 carrying avrRpt2 did not. The induction patterns of the AIG genes and EL13 demonstrate that different resistance gene-avr gene combinations can elicit distinct defense responses. Furthermore, by examining the expression of AlGí and €LI3 in plants infiltrated with a mixed inoculum of ES4326 carrying avrRpt2 and ES4326 carrying avrRpmí, we found that there is interference between the RPSPand RPM1-mediated resistance responses.