Rice WRKY4 acts as a transcriptional activator mediating defense responses toward Rhizoctonia solani, the causing agent of rice sheath blight

• Published in: Plant molecular biology Vol. 89; no. 1-2; pp. 157 - 171
• Main Authors: Wang, Haihua, Meng, Jiao, Peng, Xixu, Tang, Xinke, Zhou, Pinglan, Xiang, Jianhua, Deng, Xiaobo
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.09.2015; Springer Nature B.V
• Subjects: Biochemistry; Biomedical and Life Sciences; blight; cells; Cloning, Molecular; Cyclopentanes - pharmacology; ethylene; Ethylenes - pharmacology; Gene Expression Regulation, Plant - drug effects; Gene Expression Regulation, Plant - genetics; Gene Expression Regulation, Plant - physiology; gene overexpression; genes; Genes, Plant - genetics; Genes, Plant - physiology; jasmonic acid; Life Sciences; Nicotiana - genetics; Nicotiana - physiology; Oryza - genetics; Oryza - immunology; Oryza - physiology; Oxylipins - pharmacology; Pathogens; Plant biology; Plant diseases; Plant Diseases - immunology; Plant Leaves - genetics; Plant Leaves - physiology; Plant Pathology; Plant Proteins - genetics; Plant Proteins - physiology; Plant Sciences; Plants, Genetically Modified - genetics; Plants, Genetically Modified - physiology; promoter regions; Proteins; Rhizoctonia; Rhizoctonia solani; Rice; RNA interference; signal transduction; Thanatephorus cucumeris; tobacco; transactivators; transcription (genetics); Transcription Factors - genetics; Transcription Factors - physiology; transcriptional activation; Yeasts; Transcription factor; Disease resistance; WRKY protein; Oryza sativa; Rhizoctonia solani
• ISSN: 0167-4412; 1573-5028; 1573-5028
• DOI: 10.1007/s11103-015-0360-8

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.