Arabidopsis NDK1 Is A Component Of ROS Signaling By Interacting With Three Catalases

Abstract

Plants sense various environmental stimuli and have specific signaling pathways to respond to these cues. We found that NDKs were phosphorylated specifically after red light irradiation in Pisum sativum (NDK-PI) and after blue light irradiation in Neurospora crassa (NDK-1). Our recent research results indicated AtNDK1, the counterpart of NDK-P1 in Arabidopsis, interacted with catalase1, 2 and 3 in yeast two-hybrid assay and co-migrated in native-PAGE. Transgenic plants expressing AtNDK1 under the control of CaMV 35S promoter, AtNDK1-EX plants, showed elevated tolerance to paraquat treatment (Fukamatsu et al. 2003). In this study, crude extracts prepared from transgenic plants expressing HisAtNDK1^P93S (AtNDK1P93S-EX plants) exhibited different mode of HisAtNDK1^P93S phosphorylation compared with that of AtNDK1 from AtNDK1-EX plants. When crude extract from HisAtNDK1^P93S-EX plant treated with paraquat was separated on native-PAGE, fraction with catalase activity showed faster electrophoretic mobility on the gel, suggesting possible alteration in the level of catalase oxidation.