Abstract
We applied chemical biology approach to investigate Arabidopsis responses to bacterial pathogen Pseudomonas syringae pv. tomato DC3000 (avrRpm1). A high-throughput screening method for HR cell death, an indicator of defense, was established using Arabidopsis suspension cells. A large number of chemical agents that inhibit or enhance defense response were isolated. We classified HR cell death potentiators, based on its pharmacological property or structural similarity into 15 classes. Application of these potentiators induces PR1 gene expression in Arabidopsis seedlings. The PR1 gene induction of 13 chemicals was diminished in salicylic acid (SA)-deficient (sid2) mutant. Furthermore, the treatment of these 13 chemicals induced accumulation of SA in suspension cells. Those results indicate that the 13 chemicals act upstream of SID2 and activate SA synthesis and the others mimic the mode of action of SA.
