title: CaCDPK15 positively regulates pepper responses to Ralstonia solanacearum inoculation and forms a positive-feedback loop with CaWRKY40 to amplify defense signaling.
abstract: CaWRKY40 is a positive regulator of pepper (Capsicum annum) response to Ralstonia solanacearum inoculation (RSI), but the underlying mechanism remains largely unknown. Here, we functionally characterize CaCDPK15 in the defense signaling mediated by CaWRKY40. Pathogen-responsive TGA, W, and ERE boxes were identified in the CaCDPK15 promoter (pCaCDPK15), and pCaCDPK15-driven GUS expression was significantly enhanced in response to RSI and exogenously applied salicylic acid, methyl jasmonate, abscisic acid, and ethephon. Virus-induced gene silencing (VIGS) of CaCDPK15 significantly increased the susceptibility of pepper to RSI and downregulated the immunity-associated markers CaNPR1, CaPR1, and CaDEF1. By contrast, transient CaCDPK15 overexpression significantly activated hypersensitive response associated cell death, upregulated the immunity-associated marker genes, upregulated CaWRKY40 expression, and enriched CaWRKY40 at the promoters of its targets genes. Although CaCDPK15 failed to interact with CaWRKY40, the direct binding of CaWRKY40 to pCaCDPK15 was detected by chromatin immunoprecipitation, which was significantly potentiated by RSI in pepper plants. These combined results suggest that RSI in pepper induces CaCDPK15 and indirectly activates downstream CaWRKY40, which in turn potentiates CaCDPK15 expression. This positive-feedback loop would amplify defense signaling against RSI and efficiently activate strong plant immunity.
authors.affiliation: National Education Ministry, Key Laboratory of Plant Genetic Improvement and Comprehensive Utilization, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, PR China.|College of Crop Science, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, PR China.
authors.forename: Lei
authors.initials: L
authors.lastname: Shen
authors.affiliation: National Education Ministry, Key Laboratory of Plant Genetic Improvement and Comprehensive Utilization, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, PR China.|College of Crop Science, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, PR China.
authors.forename: Sheng
authors.initials: S
authors.lastname: Yang
authors.affiliation: National Education Ministry, Key Laboratory of Plant Genetic Improvement and Comprehensive Utilization, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, PR China.|College of Life Science, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, PR China.
authors.forename: Tong
authors.initials: T
authors.lastname: Yang
authors.affiliation: National Education Ministry, Key Laboratory of Plant Genetic Improvement and Comprehensive Utilization, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, PR China.|College of Life Science, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, PR China.
authors.forename: Jiaqi
authors.initials: J
authors.lastname: Liang
authors.affiliation: National Education Ministry, Key Laboratory of Plant Genetic Improvement and Comprehensive Utilization, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, PR China.|College of Crop Science, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, PR China.
authors.forename: Wei
authors.initials: W
authors.lastname: Cheng
authors.affiliation: National Education Ministry, Key Laboratory of Plant Genetic Improvement and Comprehensive Utilization, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, PR China.|College of Crop Science, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, PR China.
authors.forename: Jiayu
authors.initials: J
authors.lastname: Wen
authors.affiliation: National Education Ministry, Key Laboratory of Plant Genetic Improvement and Comprehensive Utilization, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, PR China.|College of Crop Science, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, PR China.
authors.forename: Yanyan
authors.initials: Y
authors.lastname: Liu
authors.affiliation: National Education Ministry, Key Laboratory of Plant Genetic Improvement and Comprehensive Utilization, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, PR China.|College of Life Science, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, PR China.
authors.forename: Jiazhi
authors.initials: J
authors.lastname: Li
authors.affiliation: National Education Ministry, Key Laboratory of Plant Genetic Improvement and Comprehensive Utilization, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, PR China.|College of Crop Science, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, PR China.
authors.forename: Lanping
authors.initials: L
authors.lastname: Shi
authors.affiliation: National Education Ministry, Key Laboratory of Plant Genetic Improvement and Comprehensive Utilization, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, PR China.|College of Crop Science, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, PR China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Tang
authors.affiliation: National Education Ministry, Key Laboratory of Plant Genetic Improvement and Comprehensive Utilization, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, PR China.|College of Crop Science, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, PR China.
authors.forename: Wei
authors.initials: W
authors.lastname: Shi
authors.affiliation: National Education Ministry, Key Laboratory of Plant Genetic Improvement and Comprehensive Utilization, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, PR China.|College of Crop Science, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, PR China.
authors.forename: Jiong
authors.initials: J
authors.lastname: Hu
authors.affiliation: National Education Ministry, Key Laboratory of Plant Genetic Improvement and Comprehensive Utilization, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, PR China.|College of Crop Science, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, PR China.
authors.forename: Cailing
authors.initials: C
authors.lastname: Liu
authors.affiliation: National Education Ministry, Key Laboratory of Plant Genetic Improvement and Comprehensive Utilization, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, PR China.|College of Crop Science, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, PR China.
authors.forename: Yangwen
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: National Education Ministry, Key Laboratory of Plant Genetic Improvement and Comprehensive Utilization, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, PR China.|College of Life Science, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, PR China.
authors.forename: Shaoliang
authors.initials: S
authors.lastname: Mou
authors.affiliation: National Education Ministry, Key Laboratory of Plant Genetic Improvement and Comprehensive Utilization, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, PR China.|College of Crop Science, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, PR China.
authors.forename: Zhiqin
authors.initials: Z
authors.lastname: Liu
authors.affiliation: National Education Ministry, Key Laboratory of Plant Genetic Improvement and Comprehensive Utilization, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, PR China.|College of Life Science, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, PR China.
authors.forename: Hanyang
authors.initials: H
authors.lastname: Cai
authors.affiliation: College of Life Science, Jinggang Shan University, Ji'an, Jiangxi 343000, PR China.
authors.forename: Li
authors.initials: L
authors.lastname: He
authors.affiliation: National Education Ministry, Key Laboratory of Plant Genetic Improvement and Comprehensive Utilization, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, PR China.|College of Crop Science, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, PR China.
authors.forename: Deyi
authors.initials: D
authors.lastname: Guan
authors.affiliation: College of Life Science, Jinggang Shan University, Ji'an, Jiangxi 343000, PR China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Wu
authors.affiliation: National Education Ministry, Key Laboratory of Plant Genetic Improvement and Comprehensive Utilization, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, PR China.|College of Crop Science, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, PR China.
authors.forename: Shuilin
authors.initials: S
authors.lastname: He
mesh_terms: D000040:Abscisic Acid / Q000494:pharmacology; D000085:Acetates / Q000494:pharmacology; D002212:Capsicum / Q000378:metabolism* / Q000382:microbiology; D016923:Cell Death / Q000235:genetics; D003517:Cyclopentanes / Q000494:pharmacology; D060467:Disease Resistance / Q000235:genetics* / Q000276:immunology; D018506:Gene Expression Regulation, Plant / Q000235:genetics; D020868:Gene Silencing; D006861:Hydrogen Peroxide / Q000378:metabolism; D009943:Organophosphorus Compounds / Q000494:pharmacology; D054883:Oxylipins / Q000494:pharmacology; D010935:Plant Diseases / Q000382:microbiology; D010937:Plant Growth Regulators / Q000494:pharmacology; D011401:Promoter Regions, Genetic / Q000235:genetics; D011485:Protein Binding; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism*; D043368:Ralstonia solanacearum / Q000502:physiology*; D020156:Salicylic Acid / Q000494:pharmacology; D015398:Signal Transduction / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D017871:Calcium-Calmodulin-Dependent Protein Kinases
chemical_list: D000040:Abscisic Acid; D000085:Acetates; D003517:Cyclopentanes; D006861:Hydrogen Peroxide; D009943:Organophosphorus Compounds; D054883:Oxylipins; D010937:Plant Growth Regulators; D011494:Protein Kinases; D020156:Salicylic Acid; D014157:Transcription Factors; D017871:Calcium-Calmodulin-Dependent Protein Kinases; C072239:methyl jasmonate; C005073:ethephon