RESEARCH-PGR: Defining the Sumoylation System in Maize and Its Roles in Stress Protection

农作物需要合适的机制才能在不利的环境中生存和表现良好，以保持高生产率。最近，一种名为相扑的小蛋白质被发现，它似乎可以保护植物免受高温和干旱等环境压力的影响。最近对暴露在环境压力下的植物进行的实验表明，相扑蛋白可能会显著影响基因在这些不利条件下的表达方式。相扑蛋白迅速并可逆地附着在一组蛋白质上，这些蛋白质在环境压力期间影响基因表达模式。该项目的目标是了解相扑在逆境中的功能，并确定在作物中操纵相扑是否可能提供提高逆境耐受性的新方法。这个项目将描述相扑蛋白的作用模式，并识别在压力下与相扑相互作用的所有其他蛋白。为了帮助理解相扑如何帮助玉米在逆境中生存，我们还将确定为什么缺少关键成分的玉米突变体现在对逆境高度敏感。总而言之，这项基础性研究将确定玉米SUMO化的关键点，这些关键点不仅在玉米中，而且在其他作物中也可以用来改善逆境保护。该项目将在圣路易斯的华盛顿大学培养博士后、研究生和本科生。它还将开发与相扑和抗逆性相关的专利技术，可以可持续地提高粮食和生物燃料作物的产量。SUMO是真核生物中有影响力的调节因子，其作用是在翻译后添加到其他细胞内蛋白质之后。最近对拟南芥的研究发现，SUMO化在逆境中选择性地修改了一些关键的调节因子，影响了染色质的可及性、DNA/组蛋白的修饰、转录、核孔功能和mRNA的加工/输出。它们的联合活性表明，胁迫诱导的SUMO化有助于植物可逆地调整染色质结构和由此产生的RNA景观，以更好地在不利条件下生存。不幸的是，农作物缺乏对相扑的欣赏，从而排除了为农业利益而进行理性重新设计的可能性。为了克服这一知识差距，该项目将定义玉米(Zea Mays)的SUMO化作用，将我们最近成功地创造种质以通过蛋白质组学方法研究相扑作为基本背景。该项目将：(I)描述玉米相扑系统如何以生化方式工作并响应各种环境挑战；(Ii)将表达标记相扑的转基因品系与已建立的质谱学方法相结合，以确定玉米‘SUMOylome’及其连锁位点；(Iii)定量确定单个靶标的苏莫化状态如何受到逆境的影响；以及(Iv)通过对Mu转座或CRISPR/Cas9基因编辑技术产生的系统突变的表型和生化分析，了解相扑如何帮助玉米在不利环境中生存。总而言之，该项目将产生急需的试剂、技术和突变体，有助于确定相扑在逆境中如何重组玉米染色质及其转录组，并确定SUMO化中的关键点，这些关键点可以被操纵以提高许多作物的逆境保护能力。

Crop plants require suitable mechanisms to survive and perform well under unfavorable environments in order to maintain high productivity. Recently, a small protein called SUMO was discovered, and it appears to protect plants against environmental stresses like heat and drought. Recent experiments with plants exposed to environmental stresses have shown that the SUMO protein may significantly affect how genes are expressed under those unfavorable conditions. The SUMO protein becomes rapidly and reversibly attached to a group of proteins that affect the pattern of gene expression during environmental stress. The goals of this project are to understand the functions of SUMO during stress and determine whether its manipulation in crops might provide novel approaches to improve stress tolerance. This project will characterize the mode of action of the SUMO protein, and identify all the other proteins that interact with SUMO under stress. To help understand how SUMO helps maize survive stress, we will also determine why maize mutants missing key components are now hypersensitive to stress. Collectively, this fundamental research will identify key points in maize SUMOylation that can be exploited to improve stress protection, not only in maize but in other crops as well. This project will train postdocs, graduate students, and undergraduates at Washington University in St. Louis. It will also develop patentable technologies related SUMO and stress tolerance that can sustainably enhance food and biofuel crop yield.SUMO is an influential regulator in eukaryotes that works following its post-translation addition to other intracellular proteins. Recent studies with Arabidopsis discovered that SUMOylation selectively modifies a number of critical regulators during stress that impact chromatin accessibility, DNA/histone modification, transcription, nuclear pore function, and mRNA processing/export. Their combined activities imply that stress-induced SUMOylation helps plants reversibly adjust chromatin architecture and the resulting RNA landscape to better survive adverse conditions. Unfortunately, appreciation of SUMO is lacking for crops, thus precluding rational redesign for agricultural benefit. To overcome this knowledge gap, this project will define how SUMOylation works in maize (Zea mays), using as essential backdrops our recent success in creating germplasm to study SUMO via proteomic approaches. This project will: (i) describe how the maize SUMO system works biochemically and responds to various environmental challenges, (ii) combine transgenic lines expressing tagged SUMOs with established mass spectrometric methods to define the maize 'SUMOylome' and its linkage sites, (iii) determine quantitatively how the SUMOylation status of individual targets is impacted by stress, and (iv) understand how SUMO helps maize survive adverse environments through the phenotypic and biochemical analyses of system mutants generated by either Mu transposition or CRISPR/Cas9 gene editing technologies. Collectively, this project will generate much-needed reagents, techniques, and mutants that will help define how SUMO reorganizes maize chromatin and its transcriptome during stress, and identify key points in SUMOylation that can be manipulated to improve stress protection in many crop species.