Plant Cell Wall Cellulose - Simple Polymer, Complexed Biosynthesis

植物细胞壁纤维素 - 简单聚合物，复杂生物合成

• 批准号: RGPIN-2017-04566
• 负责人: Mansfield, Shawn
• 金额: $ 6.56万
• 依托单位: University of British Columbia
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=709699
• 关键词: Plant; Cell; Wall; Cellulose; Simple

Plants possess an inherent plasticity in their ability to allocate carbon, which is pivotal to the effective modulation of growth and development. Moreover, plants have developed a complex regulatory system to optimize carbon assimilation within an array of dynamic environmental stimuli that is key to shaping their fitness and survival. Across species, it has been shown that there is an evolutionarily conserved relationship between leaf photosynthetic capacity and biomass investment in leaf area. Given that source tissue (i.e., mature leaves) governs the availability of carbohydrates essential for plant development, it is fair to postulate that the products of primary metabolism are therefore intricately involved in mediating plant growth and development. Sucrose is central to metabolism and is the dominant metabolite produced via photosynthesis, and in vascular plants the most commonly translocated metabolite that ultimately provides carbon for a variety of biosynthetic reactions. Among the many cellular processes that draw on these carbon skeletons, cell wall biosynthesis is a significant sink and culminates in a terminal product. The resulting chemistry and ultrastructure of the cell walls defines the physiology of the plant and, importantly, impacts form, function and fitness. The long-term objectives of the Mansfield research program is to understand the complex fundamental processes that govern carbon allocation in plants, using poplar trees (Populus spp.) and Arabidopsis as model species, with a specific emphasis on the intricacies of the biosynthetic processes governing carbohydrate metabolism and plant cell wall development. This information is key to understanding programmed cellular growth patterns, and the complex network and regulatory frameworks fundamental to xylem development (secondary cell walls). The proposed research builds on previous Discovery Grants that formed the foundations of the hypotheses to be tested. Specifically, this proposed research program is comprised of a series of experiments aimed at addressing the following questions: 1) What is the source of UDP-glucose during active cellulose deposition? 2) What role do “accessory” enzymes have in cellulose biosynthesis? 3) How is sucrose homeostasis maintained in sink tissues? A greater understanding of the molecular underpinnings of resource allocation, and the intricacies of plant secondary cell wall biosynthesis will contribute, not only to our knowledge gaps in fundamental plant biology, but also could facilitate strategies for breeding and/or engineering plants to maximize resource allocation and combat a changing climate.

植物在分配碳的能力上具有内在的可塑性，这是有效调节生长和发育的关键。此外，植物已经开发了一种复杂的调控系统，在一系列动态环境刺激中优化碳同化，这是塑造植物健康和生存的关键。在物种间，研究表明，叶片的光合作用能力和叶面积的生物量投资之间存在进化上的保守关系。由于源组织(即成熟的叶片)控制着植物发育所必需的碳水化合物的可获得性，因此可以公平地假设，初级代谢产物复杂地参与调节植物的生长和发育。蔗糖是新陈代谢的中心，是光合作用产生的主要代谢物，在维管植物中是最常见的运输代谢物，最终为各种生物合成反应提供碳。在利用这些碳骨架的许多细胞过程中，细胞壁生物合成是一个重要的汇，并最终形成最终产品。由此产生的细胞壁的化学和超微结构定义了植物的生理，更重要的是，影响了植物的形态、功能和适应性。曼斯菲尔德研究计划的长期目标是了解控制植物碳分配的复杂基本过程，使用杨树(Pillius spp.)和拟南芥作为模式物种，特别强调控制碳水化合物代谢和植物细胞壁发育的生物合成过程的错综复杂。这些信息对于理解程序化的细胞生长模式，以及木质部发育的基本复杂网络和调控框架(次生细胞壁)是关键。这项拟议的研究建立在之前的发现拨款的基础上，这些拨款构成了将要测试的假设的基础。具体地说，这项拟议的研究计划由一系列实验组成，旨在解决以下问题：1)活性纤维素沉积过程中UDP-葡萄糖的来源是什么？2)“辅助”酶在纤维素生物合成中起什么作用？3)蔗糖在下沉组织中如何维持动态平衡？更好地了解资源分配的分子基础以及植物次生细胞壁生物合成的复杂性不仅有助于我们在基础植物生物学方面的知识空白，而且还可以促进育种和/或工程植物的战略，以最大限度地分配资源和应对不断变化的气候。