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

长寿生物，如树木，提供了一个独特的系统来研究植物如何分配碳，因为它们的多年生性质允许询问对环境线索变化的复杂反应，同时避免稀释一年生植物常见的遗传分离引起的表型反应。树木和所有植物一样，在分配碳的能力方面具有内在的可塑性，这是有效调节生长和发育的维生素。归根结底，资源分配是由基因表达控制的，基因表达转化为各种可溶性代谢物的积累，包括碳水化合物和酚类。由此产生的化学物质定义了植物的生理，并对植物的形态、功能和适应性产生了重要影响。曼斯菲尔德研究计划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的发育。这些信息对于理解程序化的细胞生长模式以及复杂的网络和调控框架至关重要，这些复杂的网络和调控框架对于碳从来源组织到下沉组织的转移至关重要，在下沉组织中，木材发育是一种重要的终端产品。这项拟议的研究建立在曼斯菲尔德实验室之前的NSERC发现拨款的基础上，以测试与塑造杨树植物碳分配的分子相互作用的广度有关的假设。具体地说，拟议的研究计划包括一系列实验，旨在解决以下目标：1)阐明杨树可运输光同化物的性质；2)追踪供应杨树发育木质部的碳的命运；3)剖析杨树库区组织中蔗糖合成、果糖循环和碳水化合物信号转导之间的相互作用。更好地了解支撑树木资源分配的分子控制也可以促进旨在选择、繁育和/或工程树木的战略，使资源分配最大化，并从战略上将碳引导到营养生物量。

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.