Molecular Basis of NLR-Mediated Innate Immunity in Arabidopsis thaliana

项目描述（由申请人提供）：本项目的长期目标是阐明植物对细菌病原体的先天免疫的分子基础。本应用将通过实验来阐明拟南芥NLR类先天免疫受体识别细菌病原体的分子基础。这些研究的主要目的是鉴定和表征由NLR蛋白激活引起的下游信号事件。NLR蛋白家族免疫受体最初在植物中被描述为控制植物抗病性的主要抗病(R)蛋白。随后，人们发现这类蛋白质在动物中也起着先天免疫受体的作用，迄今为止已经描述了20多种。我们的研究将集中在NDR1和RIN4蛋白在PAMP和效应触发免疫中的作用。我们最近的研究结果表明，NDR1蛋白既影响flg22诱导的先天免疫，也影响RPS2信号转导途径。有趣的是，NDR1与LEA14蛋白共享蛋白质折叠和预测的3-D结构，LEA14蛋白已被证明参与非生物应激反应。预测的NDR1的三维结构将使我们能够通过突变预测参与功能的氨基酸来进行结构和功能分析，并使我们能够确定NDR1在免疫受体定位和信号转导中所起的作用。此外，我们建议研究拟南芥RIN4蛋白负调控RPS2蛋白并随后激活AvrRpt2效应蛋白的相关分子事件。一旦RPS2蛋白被激活，该应用程序将通过采用下一代Illumina测序技术以及一个综合的酵母- 1杂交文库来识别和表征活化的RPS2蛋白的直接靶标，该文库代表了迄今为止已知的拟南芥中所有转录因子。为了实现这些目标，将设计实验方法，结合生化、遗传、细胞、蛋白质组学和功能基因组学方法来表征控制该模型病理系统中抗病性表达的信号转导事件。

DESCRIPTION (provided by applicant): The long-term objectives of this project are to elucidate the molecular basis of plant innate immunity in response to bacterial pathogens. In this application, experiments will be carried out to elucidate the molecular basis of bacterial pathogen recognition by the NLR class of innate immune receptors in Arabidopsis thaliana. A major aim of these studies is the identification and characterization of the downstream signaling events that result from the activation of NLR proteins. The NLR protein family of immune receptors was originally described in plants as the major class of disease resistance (R) proteins that control disease resistance in plants. Subsequently, it was discovered that this class of protein also functions in animals as innate immune receptors as more than twenty have been described to date. Our research will focus on the role of the NDR1 and RIN4 proteins in both PAMP and effector-triggered immunity. Our recent results have revealed that NDR1 protein compromises both flg22-induced innate immunity and the RPS2 signal transduction pathway. Interestingly, the NDR1 shares protein folds and a predicted 3-D structure with the LEA14 protein that has been shown to be involved in abiotic stress responses. The predicted 3-D structure of NDR1 will allow us to perform a structure and function analysis by mutating amino acids that are predicted to be involved function and will allow us to ascertain the role NDR1 plays in immune receptor location and signal transduction. Furthermore, we propose to study the molecular events associated with the negative regulation of the RPS2 protein by the Arabidopsis RIN4 protein and the subsequent activation the AvrRpt2 effector protein. Once the RPS2 protein is activated, this application will identify and characterize the direct targets of the activated RPS2 protein by employing next-generation Illumina sequencing technologies in conjunction with a comprehensive yeast-one hybrid library that represents all the transcription factors known to date in Arabidopsis. To accomplish these goals, experimental approaches will be designed to employ a combination of biochemical, genetic, cellular, proteomic and functional genomic approaches to characterize the signal transduction events controlling the expression of disease resistance in this model pathosystem. PUBLIC HEALTH RELEVANCE: Our research goal is to provide a molecular understanding of the biochemical events that are involved in activating NLR immune receptor proteins in plants. Understanding the molecular basis of NLR protein activation by pathogen signals will provide novel insights and provide an mechanistic explanation as to how these proteins function and ultimately will lead to the development of innovative strategies for the control of infectious and auto-immune disease in both animals and plants.