Pathogen-Induced WRKY DNA-Binding Proteins as Regulators of Plant Defense Responses

病原体诱导的 WRKY DNA 结合蛋白作为植物防御反应的调节剂

• 批准号: 9905976
• 负责人: Zhixiang Chen
• 金额: $ 33万
• 依托单位: Regents of the University of Idaho
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-10-01 至 2002-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9905976&HistoricalAwards=false
• 关键词: Pathogen; Induced; WRKY; DNA; Binding

A protein (designated TDBA12) from tobacco plants has been identified that has sequence-specific DNA-binding activity, and that increases markedly during the hypersensitive response to infection with tobacco mosaic virus (TMV) and following treatment with salicylic acid. Furthermore, two genes have been isolated that encode proteins with the same DNA-binding specificity as TDBA12 and which are members of the novel WRKY family of DNA-binding proteins recently found in plants. TDBA12 is sensitive to phosphatase treatment, suggesting a role for protein phosphorylation in its activation. Potential target genes of TDBA12 include genes encoding proteins with protective and defensive functions as well as regulatory genes. Transgenic tobacco plants expressing antisense WRKY genes develop spontaneous lesions and exhibit enhanced chlorosis and necrosis after TMV infection. These observations suggest a general model in which WRKY proteins may be activated as targets of the protein kinase cascade that is activated during plant defense responses. WRKY proteins in turn may regulate these responses. The overall objective of these studies is to characterize further the WRKY DNA-binding proteins. First, the TDBA12 complex will be isolated to identify the subunits associated with DNA-binding activity and to isolate their genes. Second, transgenic approaches will be taken to decipher the functions of the WRKY genes. The phenotypes of transgenic tobacco plants expressing antisense RNAs specific for different WRKY proteins will be characterized. Third, in vitro and in vivo experiments will be used to determine if specific protein kinases are required for TDBA12 activation and, if so, whether WRKY proteins or their interacting proteins are the targets of the regulatory phosphorylation. A major effort will also be made to isolate the protein kinase that regulates the DNA-binding activity of TDBA12. These studies will advance our understanding of the molecular basis of plant disease resistance by revealing new regulatory components and mechanisms important in plant defense responses.

烟草植物中的一种蛋白质（称为 TDBA12）已被鉴定出具有序列特异性 DNA 结合活性，并且在对烟草花叶病毒 (TMV) 感染的过敏反应以及水杨酸处理后的过敏反应中显着增加。 此外，已分离出两个基因，它们编码与 TDBA12 具有相同 DNA 结合特异性的蛋白质，并且是最近在植物中发现的新型 WRKY DNA 结合蛋白家族的成员。 TDBA12 对磷酸酶处理敏感，表明蛋白质磷酸化在其激活中发挥作用。 TDBA12的潜在靶基因包括编码具有保护和防御功能的蛋白质的基因以及调节基因。 表达反义WRKY基因的转基因烟草植物在TMV感染后会出现自发病变并表现出增强的失绿和坏死。 这些观察结果提出了一个通用模型，其中 WRKY 蛋白可能作为植物防御反应期间激活的蛋白激酶级联的靶标被激活。 WRKY 蛋白反过来可能调节这些反应。 这些研究的总体目标是进一步表征 WRKY DNA 结合蛋白。 首先，将分离 TDBA12 复合物，以鉴定与 DNA 结合活性相关的亚基并分离其基因。 其次，将采用转基因方法来破译WRKY基因的功能。 将表征表达针对不同WRKY蛋白的反义RNA的转基因烟草植物的表型。 第三，体外和体内实验将用于确定 TDBA12 激活是否需要特定的蛋白激酶，如果需要，WRKY 蛋白或其相互作用蛋白是否是调节性磷酸化的目标。 我们还将努力分离调节 TDBA12 DNA 结合活性的蛋白激酶。 这些研究将通过揭示植物防御反应中重要的新调控成分和机制，增进我们对植物抗病性分子基础的理解。