The WRKY45-2 WRKY13 WRKY42 Transcriptional Regulatory Cascade Is Required for Rice Resistance to Fungal Pathogen

• Published in: Plant physiology (Bethesda) Vol. 167; no. 3; pp. 1087 - 1099
• Main Authors: Cheng, Hongtao, Liu, Hongbo, Deng, Yong, Xiao, Jinghua, Li, Xianghua, Wang, Shiping
• Format: Journal Article
• Language: English
• Published: United States American Society of Plant Biologists 01.03.2015
• Subjects: Cyclopentanes - pharmacology; Disease resistance; Disease Resistance - drug effects; fungi; Gene expression regulation; Gene Expression Regulation, Plant - drug effects; Genes; Infections; Magnaporthe - drug effects; Magnaporthe - physiology; Magnaporthe oryzae; Models, Biological; Molecular Sequence Data; Oryza - drug effects; Oryza - genetics; Oryza - immunology; Oryza - microbiology; Oxylipins - pharmacology; Pathogens; Plant Diseases - genetics; Plant Diseases - immunology; Plant Diseases - microbiology; Plant Proteins - genetics; Plant Proteins - metabolism; Plants; Plants, Genetically Modified; Promoter Regions, Genetic - genetics; Protein Binding - drug effects; Protoplasts; Repressor Proteins - metabolism; Rice; Signal Transduction - drug effects; SIGNALING AND RESPONSE; transcription (genetics); Transcription factors; Transcription Factors - genetics; Transcription Factors - metabolism; Transcription, Genetic - drug effects; Transgenic plants; Xanthomonas - drug effects; Xanthomonas - physiology
• ISSN: 0032-0889; 1532-2548; 1532-2548
• DOI: 10.1104/pp.114.256016

Blast caused by fungalMagnaporthe oryzaeis a devastating disease of rice (Oryza sativa) worldwide, and this fungus also infects barley (Hordeum vulgare). At least 11 rice WRKY transcription factors have been reported to regulate rice response toM. oryzaeeither positively or negatively. However, the relationships of these WRKYs in the rice defense signaling pathway againstM. oryzaeare unknown. Previous studies have revealed that rice WRKY13 (as a transcriptional repressor) and WRKY45-2 enhance resistance toM. oryzae.Here, we show that rice WRKY42, functioning as a transcriptional repressor, suppresses resistance toM. oryzae. WRKY42-RNA interference (RNAi) andWRKY42-overexpressing (oe) plants showed increased resistance and susceptibility toM. oryzae, accompanied by increased or reduced jasmonic acid (JA) content, respectively, compared with wild-type plants. JA pretreatment enhanced the resistance ofWRKY42-oe plants toM. oryzae. WRKY13 directly suppressedWRKY42. WRKY45-2, functioning as a transcriptional activator, directly activatedWRKY13. In addition, WRKY13 directly suppressedWRKY45-2by feedback regulation. TheWRKY13-RNAiWRKY45-2-oe andWRKY13-oeWRKY42-oe double transgenic lines showed increased susceptibility toM. oryzaecompared withWRKY45-2-oe and WRKY13-oe plants, respectively. These results suggest that the three WRKYs form a sequential transcriptional regulatory cascade. WRKY42 may negatively regulate rice response toM. oryzaeby suppressing JA signaling-related genes, andWRKY45-2transcriptionally activates WRKY13, whose encoding protein in turn transcriptionally suppressesWRKY42to regulate rice resistance toM. oryzae.