www.landesbioscience.com Plant Signaling & Behavior e24510-1 Plant Signaling & Behavior 8:6, e24510; June 2013; © 2013 Landes Bioscience

The salicylic acid (SA) signaling pathway plays an important role in the defense responses against pathogens in plants. In Arabidopsis, the transcriptional co-activator, NPR1, plays a cen-tral role in the SA pathway.1 In rice, the transcription factor, WRKY45 and OsNPR1 play a crucial role in the branched SA pathway.2,3 Arabidopsis NPR1 is degraded by the ubiquitin pro-teasome system (UPS) and a dual role is proposed for this regu-lation: prevention of unnecessary defense activation (negative role) and promotion of transcriptional activity upon reception of the SA signal (positive role).4 In rice, UPS-mediated degrada-tion was not observed with OsNPR1, however, it was observed with WRKY45.5 In addition, our previous data suggested a dual role for UPS-mediated degradation of WRKY45 similar to that for Arabidopsis NPR1.5 In Arabidopsis, phosphorylation of NPR1 facilitates its recruitment to UPS, thereby playing a critical rol