title: CaWRKY6 transcriptionally activates CaWRKY40, regulates Ralstonia solanacearum resistance, and confers high-temperature and high-humidity tolerance in pepper.
abstract: High temperature (HT), high humidity (HH), and pathogen infection often co-occur and negatively affect plant growth. However, these stress factors and plant responses are generally studied in isolation. The mechanisms of synergistic responses to combined stresses are poorly understood. We isolated the subgroup IIb WRKY family member CaWRKY6 from Capsicum annuum and performed quantitative real-time PCR analysis. CaWRKY6 expression was upregulated by individual or simultaneous treatment with HT, HH, combined HT and HH (HTHH), and Ralstonia solanacearum inoculation, and responded to exogenous application of jasmonic acid (JA), ethephon, and abscisic acid (ABA). Virus-induced gene silencing of CaWRKY6 enhanced pepper plant susceptibility to R. solanacearum and HTHH, and downregulated the hypersensitive response (HR), JA-, ethylene (ET)-, and ABA-induced marker gene expression, and thermotolerance-associated expression of CaHSP24, ER-small CaSHP, and Chl-small CaHSP. CaWRKY6 overexpression in pepper attenuated the HTHH-induced suppression of resistance to R. solanacearum infection. CaWRKY6 bound to and activated the CaWRKY40 promoter in planta, which is a pepper WRKY that regulates heat-stress tolerance and R. solanacearum resistance. CaWRKY40 silencing significantly blocked HR-induced cell death and reduced transcriptional expression of CaWRKY40. These data suggest that CaWRKY6 is a positive regulator of R. solanacearum resistance and heat-stress tolerance, which occurs in part by activating CaWRKY40.
authors: National Education Minister, 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: Hanyang
authors: H
authors: Cai
authors: National Education Minister, 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: Sheng
authors: S
authors: Yang
authors: National Education Minister, 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: Yan
authors: Y
authors: Yan
authors: National Education Minister, 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: Zhuoli
authors: Z
authors: Xiao
authors: National Education Minister, 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: Junbin
authors: J
authors: Cheng
authors: National Education Minister, 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: Ji
authors: J
authors: Wu
authors: National Education Minister, 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: Ailian
authors: A
authors: Qiu
authors: National Education Minister, 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: Yan
authors: Y
authors: Lai
authors: National Education Minister, 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: Shaoliang
authors: S
authors: Mou
authors: National Education Minister, 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: Deyi
authors: D
authors: Guan
authors: National Education Minister, 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: Ronghua
authors: R
authors: Huang
authors: National Education Minister, 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 shlhe201304@aliyun.com.
authors: Shuilin
authors: S
authors: He
mesh_terms: D000040:Abscisic Acid / Q000494:pharmacology; D001483:Base Sequence; D002212:Capsicum / Q000235:genetics* / Q000276:immunology / Q000382:microbiology; D003517:Cyclopentanes / Q000494:pharmacology; D060467:Disease Resistance; D005030:Ethylenes / Q000494:pharmacology; D018506:Gene Expression Regulation, Plant; D006358:Hot Temperature; D006813:Humidity; D008969:Molecular Sequence Data; D009943:Organophosphorus Compounds / Q000494:pharmacology; D054883:Oxylipins / Q000494:pharmacology; D010935:Plant Diseases / Q000276:immunology*; D010937:Plant Growth Regulators / Q000494:pharmacology*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified; D043368:Ralstonia solanacearum / Q000502:physiology*; D017422:Sequence Analysis, DNA; D013312:Stress, Physiological; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
chemical_list: D003517:Cyclopentanes; D005030:Ethylenes; D009943:Organophosphorus Compounds; D054883:Oxylipins; D010937:Plant Growth Regulators; D010940:Plant Proteins; D014157:Transcription Factors; C011006:jasmonic acid; D000040:Abscisic Acid; C036216:ethylene; C005073:ethephon
keywords: CaWRKY6; Capsicum annuum; Ralstonia solanacearum.; high temperature and high humidity