Molecular characterization of oxidative signaling derived from chloroplasts

Abstract

Oxidative signaling via reactive oxygen species (ROS) is essential for plant response to abiotic and botic stresses. To clarify molecular mechanism of oxidative signaling derived from chloroplasts, we have created the system for transient suppression of thylakoid membrane-bound ascorbate peroxidase in Arabidopsis plants. Microarray analysis using this system revealed that ROS derived from chloroplasts affect the expression of approximately 800 genes, including genes involved in the oxidative signaling. Here we isolated and characterized paraquat-induced photooxidative stress sensitive (pss) and insensitive(psi) mutants from knockout lines lacking each ROS-responsive gene.
Among 241 lines, several psi and pss mutants were isolated and characterized. Some PSI and PSS genes encoded transcription factors and protein kinases, which are responsive to pathogens. The transcript levels of almost PSSs and PSIs were changed in response to high light or treatment with paraquat. Now, we are analyzing sensitivity of the mutants to treatment with salicylic acid or elicitor to clarify the function of each PSI and PSS gene.