Abstract
OsPti1a negatively regulates R gene-mediated disease resistance in rice. Cultured cell of ospti1a mutant was highly sensitive against H2O2 treatment as compared with WT. It is suggested that OsPti1a negatively regulates ROS-mediated cell death induction. To investigate the signal transduction via OsPti1a, we analyzed OsPti1a-interacting protein 1 (PIP1), which belongs to AGC protein kinase and similar to oxidative signal inducible1 (OXI1) in Arabidopsis thaliana. OXI1 is essential part of the ROS signal transduction. It is possible that PIP1 is involved in ROS signaling. AGC kinases are regulated by 3-phosphoinotiside dependent protein kinase1 (PDK1). To investigate whether PIP1 interacted with PDK1, we performed yeast two-hybrid assay and in vitro phosphorylation assay. PIP1 was interacted with PDK1, and was phosphorylated by PDK1. These results indicate that PIP1 and PDK1 are involved in signal transduction via OsPti1a.
