Plant Cell Wall Cellulose - Simple Polymer, Complexed Biosynthesis

植物在分配碳的能力方面具有固有的可塑性，这对于有效调节生长和发育至关重要。此外，植物已经开发出一个复杂的调节系统，以优化一系列动态环境刺激中的碳同化，这是塑造其适应性和生存的关键。跨物种，它已被证明，有一个进化保守的叶光合能力和叶面积的生物量投资之间的关系。考虑到源组织（即，成熟叶）控制植物发育所必需的碳水化合物的可用性，因此可以公平地假设初级代谢的产物复杂地参与介导植物生长和发育。蔗糖是代谢的核心，是通过光合作用产生的主要代谢物，并且在维管植物中是最终为各种生物合成反应提供碳的最常见的易位代谢物。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，并在最终产物中达到高潮。由此产生的细胞壁的化学和超微结构定义了植物的生理学，重要的是，影响形式，功能和健身。曼斯菲尔德研究计划的长期目标是了解植物中碳分配的复杂基本过程，使用白杨（杨属）。和拟南芥作为模式物种，特别强调了复杂的生物合成过程中的碳水化合物代谢和植物细胞壁的发展。这些信息是理解程序化细胞生长模式以及木质部发育（次生细胞壁）的复杂网络和调控框架的关键。拟议的研究建立在之前的发现赠款的基础上，这些赠款构成了待测试假设的基础。具体来说，这个拟议的研究计划是由一系列的实验，旨在解决以下问题：1）什么是活性纤维素沉积过程中的UDP-葡萄糖的来源？2)在纤维素生物合成中，“辅助”酶起什么作用？3)蔗糖是如何在库组织中维持稳态的？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差距，而且还可以促进育种和/或工程植物的策略，以最大限度地分配资源，应对气候变化。

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.