Pseudomonas syringae pv. tomato oxidative stress-regulated transcription factors play an important role for virulence in tomato and Arabidopsis
Y. ISHIGA (1), Y. Ichinose (2) (1) University of Tsukuba, Japan; (2) Okayama University, Japan

Reactive oxygen species (ROS) have a crucial role in plant defense responses and signaling pathways. In addition, ROS also have direct toxicity against invading pathogens. However, the molecular mechanisms of plant ROS in the direct effects against pathogens is still unclear. To investigate the function of plant ROS in the interactions of plant and bacterial pathogens, we focused on the oxidative stress-regulated transcription factors including OxyR and FinR in Pseudomonas syringae pv. tomato DC3000 (Pst DC3000), and generated oxyR and finR mutants. The Pst DC3000 oxyR and finR mutants showed high sensitivity to oxidative stress in comparison to the wild-type. The host plants of Pst DC3000 including tomato and Arabidopsis inoculated with the oxyR and finR mutants showed reduced disease symptoms as well as reduced bacterial populations. Expression profiles of Pst DC3000 genes revealed that OxyR and FinR could regulate the expression of genes related to oxidative stress. We also demonstrated that the expression of catalase could be regulated by OxyR during the infection of Pst DC3000 in Arabidopsis. These results suggest that OxyR and FinR have an important role in the virulence of Pst DC3000 by regulating the expression of genes related to oxidative stress.

Abstract Number: P8-228
Session Type: Poster