Abstract
Plants change expression of numerous genes upon pathogens attack, and many of the changes compose plant defense mechanisms. The hrcC mutant of the bacterial pathogen Pseudomonas syringae pv. tomato DC3000 is defect in injecting type III effectors (T3Es) into the plant cell, and plant responses induced by the mutant strain is considered mostly based on recognition of pathogen-associated molecular patterns (PAMPs). It is not clear whether PAMPs have any effects on salicylic acid (SA) -mediated responses, which are induced by recognition of some T3Es. Several Arabidopsis defense mutants were analyzed by mRNA profiling using a small-scale custom microarray after inoculation of the hrcC strain. We found that induction of some genes by the hrcC strain depends on the ICS1 gene, which is essential for the pathogen-induced SA synthesis. This strongly suggests that PAMPs can induce SA-mediated defense responses. We will also discuss expression profiles of other Arabidopsis mutants.
