Structural and Functional Study of Protein Post-Translational Modifications involved in Plant Stress Signaling

干旱、洪水、盐碱化或极端温度等非生物胁迫可严重降低主要农作物的产量，而且随着气候变化的影响变得更加明显，这些损失正在增加。植物在分子水平上对非生物胁迫的反应是通过触发信号传导途径，导致许多基因表达的变化，使植物适应新的环境。泛素化和SUMO化是两种翻译后修饰，其中泛素或SUMO（小泛素样修饰物）蛋白共价连接到靶蛋白，越来越多地被认为在这些途径的调节中发挥重要作用。然而，它们如何在分子水平上运作仍然非常难以捉摸。我的研究计划的总体目标是在结构和功能上表征参与植物响应非生物胁迫的泛素化和SUMO化事件的分子决定因素，以便可以合理地设计或选择更好的抗逆植物突变体。为实现这一目标，将处理以下三个具体目标：*1。确定植物非生物胁迫反应中涉及的特异性和有效的SUMO化事件的分子决定因素。* 2.确定植物如何在分子水平上平衡生长和胁迫反应，通过表征赤霉素信号通路中的特定翻译后修饰事件，赤霉素是植物生长调节剂家族，也参与植物胁迫反应。3.通过模式生物拟南芥的功能分析，了解所选择的个体和集体E3-底物相互作用对植物非生物胁迫反应的贡献。**在这样做的过程中，我们的研究计划将产生一个框架，用于理解在分子水平上参与植物胁迫反应的相互作用，对翻译后修饰特别感兴趣，因为这些可以快速重塑整个反应途径。这将有助于设计或选择对非生物胁迫具有更高耐受性的植物。赤霉素和SUMO化途径的突变体已经是作物改良的有吸引力的目标。我们获得的结构信息将进一步允许以非常有针对性和可调的方式对农艺学上有用的植物进行基因工程。此外，分子决定因素的鉴定及其在应激反应中的有效作用，将有助于预测基因组群体中自然变异的影响。然后，可以通过标记辅助育种策略分离这些变体，并将构成转基因植物商业开发的替代方案。因此，我们的研究计划应该提供重要的利益，加拿大农业的背景下，对全球农业的压力稳步增加，随着世界人口的增加，农业面积缩小，和重大的气候变化。**

Abiotic stresses, such as drought, flood, salinity or extreme temperatures, can severely reduce the yield of major agricultural crops, and these losses are increasing as the effects of climate change become more pronounced. Plants respond to abiotic stresses at the molecular level by triggering signaling pathways that lead to changes in the expression of numerous genes to allow plants to acclimate to their new environment. Ubiquitination and SUMOylation, two post-translational modifications where Ubiquitin or SUMO (Small Ubiquitin-like Modifier) proteins are covalently attached to target proteins, are increasingly recognized as playing a prominent role in the modulation of these pathways. However, how they operate at the molecular level remains quite elusive. The overarching goal of my research program is to structurally and functionally characterize the molecular determinants of Ubiquitination and SUMOylation events involved in plant response to abiotic stresses so that better stress-resilient plant mutants can be rationally designed or selected. Towards this goal, the three following specific objectives will be addressed:******1. Identify the molecular determinants of specific and validated SUMOylation events involved in plant abiotic stress response.***2. Determine how plants balance growth and stress responses at the molecular level by characterizing specific post-translational modification events in the signaling pathway of gibberellins, a family of plant growth regulators that are also involved in plant stress response.***3. Understand the contribution of selected individual and collective E3-substrate interactions to plant abiotic stress response through functional analyses in the model organism Arabidopsis thaliana.******In doing so, our research program will generate a framework for understanding interactions involved in plant stress response at the molecular level, with a special interest for post-translational modifications, as these can rapidly remodel entire response pathways. This should facilitate the design or selection of plants with increased tolerance to abiotic stress. Mutants of the gibberellin and SUMOylation pathways are already attractive targets for crop improvement. Our gained structural information will further allow genetic engineering of agronomically useful plants in a very targeted and tunable manner. Also, the identification of the molecular determinants and their validated role in stress response, will help predict the effects of natural variations in genomic populations. Such variants could then be isolated through marker-assisted breeding strategies and would constitute an alternative to the commercial development of transgenic plants. Our research program should thus provide important benefits to Canadian agriculture in a context where pressure on global agriculture steadily increases with increasing world population, shrinking agricultural area, and significant climate change. **