Artificial Sweetener? A Functional Genomics Interrogation of the Impact of Soluble Carbohydrate Metabolism on Poplar Cell Wall Biosynthesis

长寿的生物，如树木，为研究植物如何分配碳提供了一个独特的系统，因为它们的多年生性质允许对环境线索变化的复杂反应进行调查，同时避免了对一年生植物常见的遗传分离引起的表型反应的稀释。与所有植物一样，树木在分配碳的能力上具有固有的可塑性，这是有效调节生长发育的关键。最终，资源分配由基因表达控制，这转化为各种可溶性代谢物的积累，包括碳水化合物和酚类物质。由此产生的化学决定了生理，重要的是，影响了植物的形态、功能和适应性。曼斯菲尔德研究项目的长期目标是了解杨树碳分配的复杂基本过程，特别强调控制可溶性碳水化合物代谢的生物合成过程的复杂性，以及这些代谢物如何促进细胞壁发育。这些信息对于理解程序化的细胞生长模式，以及碳从源组织向汇组织转移的复杂网络和调控框架至关重要，在汇组织中，木材发育是一个重要的终端产品。这项提议的研究建立在曼斯菲尔德实验室之前的NSERC发现资助的基础上，作为测试与影响杨树植物碳分配的分子相互作用广度有关的假设的基础。具体而言，该研究计划包括一系列旨在实现以下目标的实验：1)阐明杨树可易位光同化物质的性质；2)追踪杨树木质部发育过程中碳供应的命运；3)分析杨树汇组织中蔗糖合成、果糖循环和碳水化合物信号传导之间的相互作用。对支持树木资源分配的分子控制的更深入了解，也可以促进旨在选择、育种和/或工程树木的策略，使资源分配最大化，并战略性地将碳引导到植物生物量。

Long-lived organisms, such as trees, offer a unique system to investigate how plants allocate carbon, as their perennial nature permits an interrogation of the complex responses to variations in environmental cues while avoiding the dilution of phenotypic responses that arise from genetic segregation common to annual plants. Trees, like all plants, possess an inherent plasticity in their ability to allocate carbon, which is pivitol to the effective modulation of growth and development. Ultimately, resource allocation is controlled by gene expression, which translates into the accumulation of a variety of soluble metabolites, including carbohydrates and phenolics. The resulting chemistry defines the physiology and, importantly, impacts plant form, function and fitness. The long-term objectives of the Mansfield research program, is to understand the complex fundamental processes of carbon allocation in Populus, with a specific emphasis on the intricacies of the biosynthetic processes governing soluble carbohydrate metabolism and how these metabolites contribute to cell wall development. This information is pivotal to understanding programmed cellular growth patterns, and the complex network and regulatory frameworks fundamental to carbon translocation from source tissues to sink tissues, where wood development is a substantial terminal product. The proposed research builds on the previous NSERC Discovery Grants in the Mansfield lab as a foundation to test hypotheses related to the breadth of molecular interactions that shape plant carbon allocation in Populus. Specifically, the proposed research program comprises a body of experiments aimed to address the following objectives: 1) elucidate the nature of the translocatable photoassimilate in Populus; 2) track the fate of carbon supplying the developing xylem of Populus, and 3) dissect the interplay between sucrose synthesis, fructose recycling, and carbohydrate signaling in Populus sink tissue. A greater understanding of the molecular controls that underpin resource allocation in trees could also facilitate strategies aimed at selecting, breeding, and/or engineering trees that maximize resource allocation and strategically direct carbon to vegetative biomass.