title: CaWRKY40, a WRKY protein of pepper, plays an important role in the regulation of tolerance to heat stress and resistance to Ralstonia solanacearum infection.
abstract: WRKY proteins form a large family of plant transcription factors implicated in the modulation of numerous biological processes, such as growth, development and responses to various environmental stresses. However, the roles of the majority WRKY family members, especially in non-model plants, remain poorly understood. We identified CaWRKY40 from pepper. Transient expression in onion epidermal cells showed that CaWRKY40 can be targeted to nuclei and activates expression of a W-box-containing reporter gene. CaWRKY40 transcripts are induced in pepper by Ralstonia solanacearum and heat shock. To assess roles of CaWRKY40 in plant stress responses we performed gain- and loss-of-function experiments. Overexpression of CaWRKY40 enhanced resistance to R. solanacearum and tolerance to heat shock in tobacco. In contrast, silencing of CaWRKY40 enhanced susceptibility to R. solanacearum and impaired thermotolerance in pepper. Consistent with its role in multiple stress responses, we found CaWRKY40 transcripts to be induced by signalling mechanisms mediated by the stress hormones salicylic acid (SA), jasmonic acid (JA) and ethylene (ET). Overexpression of CaWRKY40 in tobacco modified the expression of hypersensitive response (HR)-associated and pathogenesis-related genes. Collectively, our results suggest that CaWRKY40 orthologs are regulated by SA, JA and ET signalling and coordinate responses to R. solanacearum attacks and heat stress in pepper and tobacco.
authors.affiliation: College of Life Science National Education Minster Key laboratory of Plant Genetic Improvement and Comprehensive Utilization, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China.
authors.forename: Feng-Feng
authors.initials: FF
authors.lastname: Dang
authors.forename: Yu-Na
authors.initials: YN
authors.lastname: Wang
authors.forename: Lu
authors.initials: L
authors.lastname: Yu
authors.forename: Thomas
authors.initials: T
authors.lastname: Eulgem
authors.forename: Yan
authors.initials: Y
authors.lastname: Lai
authors.forename: Zhi-Qin
authors.initials: ZQ
authors.lastname: Liu
authors.forename: Xu
authors.initials: X
authors.lastname: Wang
authors.forename: Ai-Lian
authors.initials: AL
authors.lastname: Qiu
authors.forename: Ting-Xiu
authors.initials: TX
authors.lastname: Zhang
authors.forename: Jing
authors.initials: J
authors.lastname: Lin
authors.forename: Yan-Sheng
authors.initials: YS
authors.lastname: Chen
authors.forename: De-Yi
authors.initials: DY
authors.lastname: Guan
authors.forename: Han-Yang
authors.initials: HY
authors.lastname: Cai
authors.forename: Shao-Liang
authors.initials: SL
authors.lastname: Mou
authors.forename: Shui-Lin
authors.initials: SL
authors.lastname: He
mesh_terms: D002212:Capsicum / Q000235:genetics* / Q000276:immunology / Q000502:physiology; D002467:Cell Nucleus / Q000378:metabolism; D003517:Cyclopentanes / Q000378:metabolism; D060467:Disease Resistance; D005030:Ethylenes / Q000378:metabolism; D015870:Gene Expression; D018506:Gene Expression Regulation, Plant; D006358:Hot Temperature; D019697:Onions / Q000235:genetics / Q000502:physiology; D054883:Oxylipins / Q000378:metabolism; D010935:Plant Diseases / Q000276:immunology* / Q000382:microbiology; D010937:Plant Growth Regulators / Q000378:metabolism*; D018515:Plant Leaves / Q000235:genetics / Q000276:immunology / Q000502:physiology; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified; D043368:Ralstonia solanacearum / Q000502:physiology*; D020156:Salicylic Acid / Q000378:metabolism / Q000494:pharmacology; D036226:Seedlings / Q000235:genetics / Q000276:immunology / Q000502:physiology; D017422:Sequence Analysis, DNA; D015398:Signal Transduction; D013312:Stress, Physiological; D014026:Nicotiana / Q000235:genetics / Q000502:physiology; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D003517:Cyclopentanes; D005030:Ethylenes; D054883:Oxylipins; D010937:Plant Growth Regulators; D010940:Plant Proteins; D014157:Transcription Factors; C011006:jasmonic acid; C036216:ethylene; D020156:Salicylic Acid