Rice WRKY4 acts as a transcriptional activator mediating defense responses toward Rhizoctonia solani, the causing agent of rice sheath blight.
WRKY transcription factors have been implicated in the regulation of transcriptional reprogramming associated with various plant processes but most notably with plant defense responses to pathogens. Here we demonstrate that expression of rice WRKY4 gene (OsWRKY4) was rapidly and strongly induced upon infection of Rhizoctonia solani, the causing agent of rice sheath blight, and exogenous jasmonic acid (JA) and ethylene (ET). OsWRKY4 is localized to the nucleus of plant cells and possesses transcriptional activation ability. Modulation of OsWRKY4 transcript levels by constitutive overexpression increases resistance to the necrotrophic sheath blight fungus, concomitant with elevated expression of JA- and ET-responsive pathogenesis-related (PR) genes such as PR1a, PR1b, PR5 and PR10/PBZ1. Suppression by RNA interference (RNAi), on the other hand, compromises resistance to the fungal pathogen. Yeast one-hybrid assay and transient expression in tobacco cells reveal that OsWRKY4 specifically binds to the promoter regions of PR1b and PR5 which contain W-box (TTGAC[C/T]), or W-box like (TGAC[C/T]) cis-elements. In conclusion, we propose that OsWRKY4 functions as an important positive regulator that is implicated in the defense responses to rice sheath blight via JA/ET-dependent signal pathway.
School of Life Science, Hunan University of Science and Technology, Taoyuan Rd., Xiangtan, 411201, Hunan, China. hhwang@hnust.edu.cn.|Key Laboratory of Integrated Management of the Pests and Diseases on Horticultural Crops in Hunan Province, Xiangtan, 411201, Hunan, China. hhwang@hnust.edu.cn.|Key Laboratory of Ecological Remediation and Safe Utilization of Heavy Metal-Polluted Soils, College of Hunan Province, Xiangtan, 411201, Hunan, China. hhwang@hnust.edu.cn.
Haihua
H
Wang
School of Life Science, Hunan University of Science and Technology, Taoyuan Rd., Xiangtan, 411201, Hunan, China.
Jiao
J
Meng
School of Life Science, Hunan University of Science and Technology, Taoyuan Rd., Xiangtan, 411201, Hunan, China.|Key Laboratory of Ecological Remediation and Safe Utilization of Heavy Metal-Polluted Soils, College of Hunan Province, Xiangtan, 411201, Hunan, China.
Xixu
X
Peng
School of Life Science, Hunan University of Science and Technology, Taoyuan Rd., Xiangtan, 411201, Hunan, China.|Key Laboratory of Integrated Management of the Pests and Diseases on Horticultural Crops in Hunan Province, Xiangtan, 411201, Hunan, China.
Xinke
X
Tang
School of Life Science, Hunan University of Science and Technology, Taoyuan Rd., Xiangtan, 411201, Hunan, China.|Key Laboratory of Integrated Management of the Pests and Diseases on Horticultural Crops in Hunan Province, Xiangtan, 411201, Hunan, China.
Pinglan
P
Zhou
School of Life Science, Hunan University of Science and Technology, Taoyuan Rd., Xiangtan, 411201, Hunan, China.
Jianhua
J
Xiang
School of Life Science, Hunan University of Science and Technology, Taoyuan Rd., Xiangtan, 411201, Hunan, China.
Xiaobo
X
Deng
D003001:Cloning, Molecular; D003517:Cyclopentanes / Q000494:pharmacology; D005030:Ethylenes / Q000494:pharmacology; D018506:Gene Expression Regulation, Plant / Q000187:drug effects / Q000235:genetics / Q000502:physiology; D017343:Genes, Plant / Q000235:genetics / Q000502:physiology; D012275:Oryza / Q000235:genetics / Q000276:immunology / Q000502:physiology*; D054883:Oxylipins / Q000494:pharmacology; D010935:Plant Diseases / Q000276:immunology*; D018515:Plant Leaves / Q000235:genetics / Q000502:physiology; D010940:Plant Proteins / Q000235:genetics / Q000502:physiology*; D030821:Plants, Genetically Modified / Q000235:genetics / Q000502:physiology; D012232:Rhizoctonia; D014026:Nicotiana / Q000235:genetics / Q000502:physiology; D014157:Transcription Factors / Q000235:genetics / Q000502:physiology*
D003517:Cyclopentanes; D005030:Ethylenes; D054883:Oxylipins; D010940:Plant Proteins; D014157:Transcription Factors; C011006:jasmonic acid; C036216:ethylene
Disease resistance; Oryza sativa; Rhizoctonia solani; Transcription factor; WRKY protein