title: The WRKY45-2 WRKY13 WRKY42 transcriptional regulatory cascade is required for rice resistance to fungal pathogen.
abstract: Blast caused by fungal Magnaporthe oryzae is 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 to M. oryzae either positively or negatively. However, the relationships of these WRKYs in the rice defense signaling pathway against M. oryzae are unknown. Previous studies have revealed that rice WRKY13 (as a transcriptional repressor) and WRKY45-2 enhance resistance to M. oryzae. Here, we show that rice WRKY42, functioning as a transcriptional repressor, suppresses resistance to M. oryzae. WRKY42-RNA interference (RNAi) and WRKY42-overexpressing (oe) plants showed increased resistance and susceptibility to M. oryzae, accompanied by increased or reduced jasmonic acid (JA) content, respectively, compared with wild-type plants. JA pretreatment enhanced the resistance of WRKY42-oe plants to M. oryzae. WRKY13 directly suppressed WRKY42. WRKY45-2, functioning as a transcriptional activator, directly activated WRKY13. In addition, WRKY13 directly suppressed WRKY45-2 by feedback regulation. The WRKY13-RNAi WRKY45-2-oe and WRKY13-oe WRKY42-oe double transgenic lines showed increased susceptibility to M. oryzae compared with WRKY45-2-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 to M. oryzae by suppressing JA signaling-related genes, and WRKY45-2 transcriptionally activates WRKY13, whose encoding protein in turn transcriptionally suppresses WRKY42 to regulate rice resistance to M. oryzae.
authors.affiliation: National Key Laboratory of Crop Genetic Improvement, National Center of Plant Gene Research (Wuhan), Huazhong Agricultural University, Wuhan 430070, China.
authors.forename: Hongtao
authors.initials: H
authors.lastname: Cheng
authors.affiliation: National Key Laboratory of Crop Genetic Improvement, National Center of Plant Gene Research (Wuhan), Huazhong Agricultural University, Wuhan 430070, China.
authors.forename: Hongbo
authors.initials: H
authors.lastname: Liu
authors.affiliation: National Key Laboratory of Crop Genetic Improvement, National Center of Plant Gene Research (Wuhan), Huazhong Agricultural University, Wuhan 430070, China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Deng
authors.affiliation: National Key Laboratory of Crop Genetic Improvement, National Center of Plant Gene Research (Wuhan), Huazhong Agricultural University, Wuhan 430070, China.
authors.forename: Jinghua
authors.initials: J
authors.lastname: Xiao
authors.affiliation: National Key Laboratory of Crop Genetic Improvement, National Center of Plant Gene Research (Wuhan), Huazhong Agricultural University, Wuhan 430070, China.
authors.forename: Xianghua
authors.initials: X
authors.lastname: Li
authors.affiliation: National Key Laboratory of Crop Genetic Improvement, National Center of Plant Gene Research (Wuhan), Huazhong Agricultural University, Wuhan 430070, China swang@mail.hzau.edu.cn.
authors.forename: Shiping
authors.initials: S
authors.lastname: Wang
mesh_terms: D003517:Cyclopentanes / Q000494:pharmacology; D060467:Disease Resistance / Q000187:drug effects; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D020082:Magnaporthe / Q000187:drug effects / Q000502:physiology*; D008954:Models, Biological; D008969:Molecular Sequence Data; D012275:Oryza / Q000187:drug effects / Q000235:genetics* / Q000276:immunology / Q000382:microbiology*; D054883:Oxylipins / Q000494:pharmacology; D010935:Plant Diseases / Q000235:genetics / Q000276:immunology / Q000382:microbiology; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified; D011401:Promoter Regions, Genetic / Q000235:genetics; D011485:Protein Binding / Q000187:drug effects; D012097:Repressor Proteins / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic / Q000187:drug effects; D014974:Xanthomonas / Q000187:drug effects / Q000502:physiology
chemical_list: D003517:Cyclopentanes; D054883:Oxylipins; D010940:Plant Proteins; D012097:Repressor Proteins; D014157:Transcription Factors; C011006:jasmonic acid