OsWRKY51, a rice transcription factor, functions as a positive regulator in defense response against Xanthomonas oryzae pv. oryzae

Abstract

OsWRKY51 functions as a positive transcriptional regulator in defense signaling against Xanthomonas oryzae pv. oryzae by direct DNA binding to the promoter of defense related gene, OsPR10a. OsWRKY51 in rice (Oryza sativa L.) is induced by exogenous salicylic acid (SA) and inoculation with Xanthomonas oryzae pv. oryzae (Xoo). To examine the role of OsWRKY51 in the defense response of rice, we generated OsWRKY51 overexpressing and underexpressing transgenic rice plants. OsWRKY51-overexpressing transgenic rice lines were more resistant to Xoo and showed greater expression of defense-related genes than wild-type (WT) plants, while OsWRKY51-underexpressing lines were more susceptible to Xoo and showed less expression of defense-associated genes than WT plants. Transgenic lines overexpressing OsWRKY51 showed growth retardation compared to WT plants. In contrast, transgenic lines underexpressing OsWRKY51 by RNA interference showed similar plant height with WT plants. Transient expression of OsWRKY51-green fluorescent protein fusion protein in rice protoplasts revealed that OsWRKY51 was localized in the nucleus. OsWRKY51 bound to the W-box and WLE1 elements of the OsPR10a promoter. Based on these results, we suggest that OsWRKY51 is a positive transcriptional regulator of defense signaling and has direct DNA binding ability to the promoter of OsPR10a, although it is reported to be a negative regulator in GA signaling.

MdWRKY15 improves resistance of apple to Botryosphaeria dothidea via the salicylic acid‐mediated pathway by directly binding the MdICS1 promoter

“…oryzae ( Xoo ). The overexpression of OsWRKY51 in rice can increase the resistance to Xoo , and OsWRKY51 binds to the OsPR10a promoter to positively regulate disease resistance (Hwang et al 2016). In poplar, the induction of PtrWRKY73 by SA can increase the disease resistance of plants, and the overexpression of PtrWRKY73 can upregulate the expression of PR1 , PR2 , and PAD4 (Duan et al 2015).…”

OsWRKY80-OsWRKY4 Module as a Positive Regulatory Circuit in Rice Resistance Against Rhizoctonia solani

“…For instance, OsWRKY13 positively mediates rice defense responses against both Xoo and M. grisea (Qiu et al 2007). OsWRKY6, 13/03, 51 and 71 also positively mediate rice resistance to Xoo (Choi et al 2015; Liu et al 2005; Hwang et al 2016; Liu et al 2007). On the other hand, some Group IIa proteins, such as OsWRKY28, 62 and 76 are transcriptional repressors, and they act as negative regulators in rice response to M. grisea or Xoo (Chujo et al 2013; Peng et al 2008; Yokotani et al 2013).…”

“…To date, at least 13 Oryza sativa WRKY ( OsWRKY ) genes are known to positively regulate rice resistance against pathogens, such as Magnaporthe oryzae , Rhizoctonia solani and Xanthomonas oryzae pv oryzae ( Xoo ) (Cheng et al 2015; Wang et al 2015; Choi et al 2015; Hwang et al 2016). For instance, OsWRKY13 activates SA-dependent defense response whereas suppresses JA-dependent response, in mediating rice defense response to bacterial blight and fungal blast pathogens (Qiu et al 2007).…”

“…OsWRKY45 positively regulates systemic acquired resistance (SAR) in an SA-dependent manner (Shimono et al 2007; Shimono et al 2012). More recently, it has been reported that OsWRKY51 functions as a positive transcriptional regulator in defense signaling against Xoo by direct binding to the promoter of defense related gene, OsPR10a (Hwang et al 2016). By contrast, although the transcription of OsWRKY28 , 62, and 76 is upregulated upon pathogen infection, their protein products act to repress plant defense response against rice fungal blast or bacterial blight pathogens (Peng et al 2008; Delteil et al 2012; Chujo et al 2013; Yokotani et al 2013).…”

Novel bacterial control agent tolprocarb enhances systemic acquired resistance in Arabidopsis and rice as a second mode of action

“…In the present study, the expression of seven of the 10 pathogenesis-related genes tested changed after treatment with the tested compounds: PBZ1, β-1,3-glucanase, chitinase 1, KSL7, and CYP99A2 related to the SA-signaling pathway and RBBI2-3 and RCI-1 related to the JA-signaling pathway (Cho et al 2004;Hwang et al 2008Hwang et al , 2016Liu et al 2005;Marla and Singh 2012;Miyamoto et al 2014b;Rakwal and Komatsu 2000;Ryan 1990;Van Loon and Van Strien 1999). KSL7 and CYP99A2 are associated with the diterpene phytoalexin pathway, KSL7 participates in the phytocassane synthesis pathway, and CYP99A2 participates in the momilactone synthesis pathway (Cho et al 2004; Miyamoto et al 2014b).…”