title: OsWRKY80-OsWRKY4 Module as a Positive Regulatory Circuit in Rice Resistance Against Rhizoctonia solani.
abstract: BACKGROUND
  Plant WRKY transcription factors play pivotal roles in diverse biological processes but most notably in plant defense response to pathogens. Sheath blight represents one of the predominant diseases in rice. However, our knowledge about the functions of WRKY proteins in rice defense against sheath blight is rather limited.
  
  
  RESULTS
  Here we demonstrate that the expression of Oryza sativa WRKY80 gene (OsWRKY80) is rapidly and strongly induced upon infection of Rhizoctonia solani, the causal agent of rice sheath blight disease. OsWRKY80 expression is also induced by exogenous jasmonic acid (JA) and ethylene (ET), but not by salicylic acid (SA). OsWRKY80-GFP is localized in the nuclei of onion epidermal cells in a transient expression assay. Consistently, OsWRKY80 exhibits transcriptional activation activity in a GAL4 assay in yeast cells. Overexpression of OsWRKY80 in rice plants significantly enhanced disease resistance to R. solani, concomitant with elevated expression of OsWRKY4, another positive regulator in rice defense against R. solani. Suppression of OsWRKY80 by RNA interference (RNAi), on the other hand, compromised disease resistance to R. solani. Results of yeast one-hybrid assay and transient expression assay in tobacco cells have revealed that OsWRKY80 specifically binds to the promoter regions of OsWRKY4, which contain W-box (TTGAC[C/T]) or W-box like (TGAC[C/T]) cis-elements.
  
  
  CONCLUSIONS
  We propose that OsWRKY80 functions upstream of OsWRKY4 as an important positive regulatory circuit that is implicated in rice defense response to sheath blight pathogen R. solani.
authors.affiliation: School of Life Science, Hunan University of Science and Technology, Taoyuan Rd., Xiangtan, Hunan, 411201, China.|Key Laboratory of Ecological Remediation and Safe Utilization of Heavy Metal-polluted Soils, College of Hunan Province, Xiangtan, Hunan, 411201, China.
authors.forename: Xixu
authors.initials: X
authors.lastname: Peng
authors.affiliation: School of Life Science, Hunan University of Science and Technology, Taoyuan Rd., Xiangtan, Hunan, 411201, China. hhwang@hnust.edu.cn.|Key Laboratory of Integrated Management of the Pests and Diseases on Horticultural Crops in Hunan Province, Xiangtan, Hunan, 411201, China. hhwang@hnust.edu.cn.|Key Laboratory of Ecological Remediation and Safe Utilization of Heavy Metal-polluted Soils, College of Hunan Province, Xiangtan, Hunan, 411201, China. hhwang@hnust.edu.cn.
authors.forename: Haihua
authors.initials: H
authors.lastname: Wang
authors.affiliation: Department of Horticulture and Crop Science, The Ohio State University, Columbus, OH, 43210, USA.|Department of Molecular Genetics, The Ohio State University, Columbus, OH, 43210, USA.|Center for Applied Plant Sciences, The Ohio State University, Columbus, OH, 43210, USA.
authors.forename: Jyan-Chyun
authors.initials: JC
authors.lastname: Jang
authors.affiliation: School of Life Science, Hunan University of Science and Technology, Taoyuan Rd., Xiangtan, Hunan, 411201, China.
authors.forename: Ting
authors.initials: T
authors.lastname: Xiao
authors.affiliation: School of Life Science, Hunan University of Science and Technology, Taoyuan Rd., Xiangtan, Hunan, 411201, China.
authors.forename: Huanhuan
authors.initials: H
authors.lastname: He
authors.affiliation: School of Life Science, Hunan University of Science and Technology, Taoyuan Rd., Xiangtan, Hunan, 411201, China.
authors.forename: Dan
authors.initials: D
authors.lastname: Jiang
authors.affiliation: School of Life Science, Hunan University of Science and Technology, Taoyuan Rd., Xiangtan, Hunan, 411201, China.|Key Laboratory of Integrated Management of the Pests and Diseases on Horticultural Crops in Hunan Province, Xiangtan, Hunan, 411201, China.
authors.forename: Xinke
authors.initials: X
authors.lastname: Tang
keywords: Disease resistance; Oryza sativa; Rhizoctonia solani; Transcription factor; WRKY protein