Role of the Unfolded Protein Response in Environmental Stress Tolerance in Maize

这项研究将调查保护玉米（美国主要的粮食、饲料和燃料作物）免受环境压力的策略。玉米可以通过一种称为未折叠蛋白反应（UPR）的过程来感知和响应不利的环境条件。折叠是蛋白质生物合成中一个关键而微妙的步骤，它很容易被不利条件（如高温）扰乱。当这种情况发生时，错误折叠的蛋白质会积聚并激活一系列应激反应基因。该项目的目标之一是深入表征基因级联，以更好地了解它们如何保护玉米免受胁迫。对其他植物的研究表明，引发UPR的应激条件也激活了一个称为自噬的过程，在这个过程中植物细胞修复应激损伤。因此，本项目的另一个目的是发现应激信号如何激活自噬机制。为了应对压力，其他植物减缓蛋白质合成，以防止蛋白质折叠过程负担过重。在这个项目中，将进行一项调查，以确定玉米是否通过降解一些编码蛋白质的信使rna来做到这一点。最后，将尝试修改普遍定期审议，并利用新的基因编辑技术更深入地探索其运作。与此同时，将重点放在本科阶段的学习和研究之间的联系上。这将通过开发易于获取的在线培训和同伴支持的学习社区来实现。在本项目中，预计将通过广泛的转录组学分析揭示玉米内质网胁迫反应的新基因靶点。预计这些靶标可以提供更清晰的细胞生存活动和细胞死亡机制，以应对压力。此外，这些分析将有助于揭示应激引起内质网增殖和自噬激活的信号通路。虽然一些UPR反应涉及应激反应基因的上调，但其他反应是由ire1依赖性RNA降解（Regulated IRE1-Dependent RNA degradation， RIDD）和microRNA作用导致的特定RNA转录物的降解引起的。在这方面，降解组和转录组将被用来确定选择性RNA转录物降解在玉米胁迫反应中的作用。该研究项目还有望通过“翻译组”分析揭示玉米中的内质网胁迫是否也通过RNA转录物翻译的选择性和/或全局调控得到缓解。选择玉米作为这些研究模型的一个令人信服的理由是，普遍定期审议已经在玉米领域得到了证明。因此，将在实验室和田间研究不同玉米品系的胁迫反应变化，目的是确定影响普遍定期审议的遗传决定因素。

This research will investigate strategies for protecting maize, the major U.S. food, feed and fuel crop, from environmental stress. Maize can perceive and respond to adverse environmental conditions through a process called the unfolded protein response (UPR). Folding is a critical, but delicate step in the biosynthesis of proteins, and it can be easily upset by adverse conditions, such as high temperature. When this happens, misfolded proteins accumulate and activate a cascade of stress response genes. One of the objects of this project is to characterize in depth the cascade of genes to better understand how they protect maize from stress. Investigations in other plants has revealed that stress conditions eliciting the UPR also activate a process called autophagy in which plant cells repair stress damage. Therefore, another aim of this project is to discover how stress signals activate the autophagy machinery. In response to stress, other plants slow down protein synthesis to prevent overburdening the process of protein folding. In this project an investigation will be conducted to determine whether maize does this by degrading some of the messenger RNAs encoding proteins. Finally, attempts will be made to modify the UPR and probe more deeply into its operation by using new gene editing techniques. In parallel, there will be a focus on links between learning and research at the undergraduate level. This will be done through the development of easily accessible training on line and peer-support learning communities.In this project, it is expected that new gene targets involved in ER stress responses in maize will be revealed through extensive transcriptomic analysis. It is anticipated that those targets may provide a clearer picture of both cell survival activities and cell death mechanisms in response to stress. In addition, these analyses will aid in uncovering the signaling pathways by which stress elicits the proliferation of the ER and activation of autophagy. While some UPR responses involve the upregulation of stress response genes, other responses result from the degradation of specific RNA transcripts brought about by Regulated IRE1-Dependent RNA Degradation (RIDD)and microRNA action. In this regard, the degradome as well as the transcriptome will be used to determine the role of selective RNA transcript degradation in maize stress responses. This research project is also expected to reveal through 'translateome' analysis whether ER stress is also mitigated in maize by selective and/or global regulation of the translation of RNA transcripts. A compelling reason for the selection of maize as a model for these studies is that the UPR has already been demonstrated in maize in the field. Therefore, variation in stress response in different lines of maize will be studied both in the laboratory and in the field with the goal of identifying genetic determinants that condition the UPR.