Wrestling with pathogens: host SUMOylation and bacterial interference in the plant immune system

在信号处理中，一个基本的“工程”问题是将触发阈值和动态范围整合到灵敏度和特异性之间的有益平衡中。一个很好的例子是免疫系统，生物体需要仔细控制它，以便在面对威胁病原体时迅速激活它，但要保持控制以防止破坏性的副作用。在植物中，最强烈的免疫反应之一是当细胞内免疫受体检测到病原体利用入侵的病原体蛋白来操纵宿主细胞时触发的，这一过程被称为效应触发免疫。该项目旨在揭示生物体校准调节免疫反应特异性和强度的复杂信号模块的原理。在实践层面上，对植物免疫反应的详细了解可能会导致作物在长期内具有更高的先天病原体抗性，对可持续农业和生物质生产以及环境有重大好处。该项目更广泛的影响还包括培养本科生和研究生以及博士后研究员。此外，该项目将支持学生参加一个名为“新生植物科学研究”（FRIPS）的校园项目，并将通过暑期课堂访问和在密苏里大学为教师组织的研究模块，进一步发展与密苏里州锡代利亚的初中和高中教师的联系。研究的重点是拟南芥中一种名为SRFR1的免疫调节因子。目前对SRFR1蛋白功能的了解表明，SRFR1是一种免疫适应蛋白，它在时间和空间上调节蛋白复合物的存在和稳定性，以微调免疫输出。在本项目中，将研究调节SRFR1蛋白-蛋白相互作用的机制。具体来说，SRFR1结合SUMO（一种附着在其他蛋白质上以调节其在细胞中的位置的小蛋白）的迹象表明，SRFR1通过SUMOylation调节其与其他蛋白质相互作用的机制。这将通过遗传学、细胞生物学和蛋白质组学的结合进行测试，以确定SRFR1客户蛋白的sumo化是否以及何时发生，以及这是否决定了蛋白质复合物的细胞位置。此外，该项目还将调查病原体是否会干扰这一过程。

A fundamental "engineering" problem in signal processing consists of integrating trigger threshold and dynamic range into a beneficial balance between sensitivity and specificity. A good example is the immune system, which organisms need to carefully control so that it can be rapidly activated when faced with a threatening pathogen, but kept in check to prevent damaging side effects. In plants, one of the strongest immune responses is triggered when intracellular immune receptors detect the presence of intruding pathogen proteins deployed by the pathogen to manipulate the host cell, a process called effector-triggered immunity. This project aims to uncover principles by which living organisms calibrate the complex signaling modules that regulate the specificity and intensity of immune responses. On a practical level, detailed knowledge of the plant immune response may lead to crop plants with improved durability of innate pathogen resistance in the long term, with significant benefits to sustainable agricultural and biomass production and the environment. This project's broader impacts also include the training of undergraduate and graduate students and of a post-doctoral researcher. In addition, the project will support students in a campus-wide program called Freshman Research in Plant Sciences (FRIPS), and will further develop connections to middle and high school teachers in Sedalia, MO, through classroom visits and the organization of research modules at MU for teachers in the summer.The focus is on an immune regulator in the plant Arabidopsis thaliana called SRFR1. Current understanding of SRFR1 protein function suggests that SRFR1 is an immune adaptor protein that temporally and spatially regulates the presence and stability of protein complexes to fine-tune immune outputs. In this project, the mechanisms that regulate SRFR1 protein-protein interactions will be investigated. Specifically, the indication that SRFR1 binds SUMO, a small protein that is attached to other proteins to regulate their location in the cell, suggests a mechanism for regulating SRFR1 interactions with other proteins by SUMOylation. This will be tested using a combination of genetics, cell biology and proteomics to establish whether and when SUMOylation of SRFR1 client proteins occurs, and whether this determines the cellular location of protein complexes. In addition, the project will investigate if pathogens interfere with this process.