Role of the Pti4 and Pti5 Transcription Factors in Pto-Mediated Defense Gene Activation and Disease Resistance

Pti4 和 Pti5 转录因子在 Pto 介导的防御基因激活和抗病性中的作用

• 批准号: 0090402
• 负责人: Gregory Martin
• 金额: $ 60万
• 依托单位: Boyce Thompson Institute Plant Research
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-04-15 至 2007-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0090402&HistoricalAwards=false
• 关键词: Role; Pti4; Pti5; Transcription; Factors

This project focuses on the molecular events that occur after a plant recognizes a bacterial pathogen and which result in increased expression of defense-related genes. To investigate these events, resistance in tomato to bacterial speck disease caused by Pseudomonas syringae pv. tomato is studied. Resistance to speck disease occurs in a "gene-for-gene" fashion when the tomato plant expresses the Pto resistance gene and the bacterium expresses the avrPto avirulence gene. Recognition of AvrPto protein by the product of the Pto gene, a serine-threonine kinase, leads to the rapid induction of many "pathogenesis-related" (PR) genes (among other defense responses). With previous NSF support, two transcription factors, Pti4 and Pti5, were identified that interact with the Pto kinase and which bind a DNA regulatory element present in the promoter of many PR genes. The Pti4 and Pti5 genes are induced in tomato leaves by Pseudomonas infection, and Pti5 expression is further increased during a Pseudomonas-tomato interaction involving AvrPto-Pto. Furthermore, the Pti4 protein is phosphorylated by the Pto kinase and its binding to the GCC box is thereby enhanced. Overexpression of Pti4 or Pti5 in plants leads to constitutive expression of certain PR genes. Thus, Pti4 and Pti5 appear to define a molecular link between the disease resistance gene Pto and activation of PR genes. Amino acids of Pti4 that are phosphorylated by Pto will be identified and the role of this phosphorylation in Pti4 activity will be determined. Genome-wide gene expression changes that occur in tomato and Arabidopsis plants overexpressing Pti4 and Pti5 will be elucidated, and these plants will be tested for alterations in disease resistance. To understand the Pto-mediated induction of Pti5, the Pseudomonas-responsive promoter elements of this gene will be determined and their cognate transcription factors will be identified. Finally, new plant loci that are required for Pti4-mediated expression of PR genes will be discovered. These studies will elucidate key steps in the regulation of transcription factors associated with plant disease resistance.

该项目的重点是植物识别细菌病原体后发生的分子事件，并导致防御相关基因的表达增加。 为了研究这些事件，番茄对细菌性斑点病的抗性由假单胞菌pv.番茄研究 当番茄植物表达Pto抗性基因而细菌表达avrPto无毒基因时，对斑点病的抗性以“基因对基因”的方式发生。 Pto基因的产物（丝氨酸-苏氨酸激酶）对AvrPto蛋白的识别导致许多“病程相关”（PR）基因（以及其他防御反应）的快速诱导。 在先前NSF的支持下，鉴定了两种转录因子Pti 4和Pti 5，它们与Pto激酶相互作用，并结合存在于许多PR基因启动子中的DNA调控元件。 Pti 4和Pti 5基因通过假单胞菌感染在番茄叶中诱导，并且Pti 5表达在涉及AvrPto-Pto的假单胞菌-番茄相互作用期间进一步增加。 此外，Pti 4蛋白被Pto激酶磷酸化，从而增强其与GCC盒的结合。 Pti 4或Pti 5在植物中的过表达导致某些PR基因的组成型表达。 因此，Pti 4和Pti 5似乎定义了抗病基因Pto和PR基因激活之间的分子联系。 将鉴定被Pto磷酸化的Pti 4的氨基酸，并确定这种磷酸化在Pti 4活性中的作用。 全基因组基因表达的变化，发生在番茄和拟南芥植物过表达Pti 4和Pti 5将被阐明，这些植物将被测试的抗病性的改变。 为了理解Pto介导的Pti 5诱导，将确定该基因的假单胞菌应答启动子元件，并鉴定其同源转录因子。 最后，将发现Pti 4介导的PR基因表达所需的新的植物基因座。 这些研究将阐明与植物抗病性相关的转录因子调控的关键步骤。