Translating extracellular ligand perception into a cytosolic Ca2+ signal: characterizing the role plant elicitor peptides and their receptor play in innate immune responses

该项目的重点是参与植物细胞免疫信号传导的信号转导系统;总体目标是确定允许植物细胞膜受体蛋白感知病原微生物的分子机制，并将这种感知转化为防御反应。信号级联中的一个重要步骤是引起下游防御程序的胞质Ca 2+升高。研究将集中在植物激发肽（Peps）家族及其细胞膜受体（PEPR 1）上。研究者将测试Pep与PEPR 1受体结合如何导致细胞溶质Ca 2+升高的模型。研究人员进行的初步研究表明，PEPR 1受体具有鸟苷酸环化酶活性。该项目将研究细胞中的信号分子环鸟苷酸（cGMP）是否在植物细胞中由受体响应导致Pep肽产生的病原体线索而产生，以及cGMP的产生是否由于细胞膜中环核苷酸门控离子通道的开放而提高胞质Ca 2+。这些免疫信号级联的早期步骤将与下游防御反应相联系，例如产生限制致病病原体生长的抗菌分子（假单胞菌）和对无毒病原体的过敏反应/程序性细胞死亡反应（P. P. P. lingae avrRpt 2）。该项目的主要研究者有招募高中生与研究生在实验室工作的历史，以及进入少数民族本科课程，并让这些学生参与研究。在拟议项目期间，将继续开展这种外联和培训活动。主要研究者与当地一所高中的生物老师持续互动，并将与该老师合作招募高中生与本科生一起沿着该项目的研究活动。

This project focuses on a signal transduction system involved in plant cell immune signaling; an overall aim is to identify molecular mechanisms that allow perception of pathogenic microbes by plant cell membrane receptor proteins and translation of this perception to defense responses. An essential step in the signaling cascade is a cytosolic Ca2+ elevation that evokes downstream defense programs. Studies will focus on a family of Plant Elicitor Peptides (Peps) and their cell membrane receptor (PEPR1). A model of how Pep binding to the PEPR1 receptor leads to cytosolic Ca2+ elevation will be tested by the investigators. Preliminary studies undertaken by the investigators indicate that the PEPR1 receptor has guanylyl cyclase activity. The project will investigate whether cyclic guanylyl monophosphate (cGMP), a signaling molecule in cells, is generated in plant cells by the receptor in response to pathogen cues causing Pep peptide generation, and if the cGMP production elevates cytosolic Ca2+ due to the opening of a cyclic nucleotide gated ion channel in the cell membrane. These early steps in the immune signaling cascade will be linked to downstream defense responses such as the generation of antimicrobial molecules that limit growth of a virulent pathogen (Pseudomonas syringae) and hypersensitive response/programmed cell death response to an avirulent pathogen (P. syringae avrRpt2).The Principal Investigator of the project has a history of recruiting high school students to work with graduate students in the laboratory, as well as accessing minority undergraduate programs and involving these students in research. This outreach and training will continue during the proposed project. The Principal Investigator has an ongoing interaction with a biology teacher at a local high school and will work with this teacher to recruit high school students to participate, along with undergraduate students, in the research activity of the project.