Biochemical and Functional Analysis of Phenolic Secondary Metabolites in Populus

杨树酚类次生代谢物的生化和功能分析

• 批准号: RGPIN-2020-06646
• 负责人: Constabel, CPeter
• 金额: $ 4.74万
• 依托单位: University of Victoria
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=745657
• 关键词: Biochemical; Functional; Analysis; Phenolic; Secondary

Trees and forests are essential components of Canada's landscape and economy. Canada's land area contains 10% of the world's forests, and represent a significant long-term carbon sink. Forest health is therefore a priority for policy and research. As climate change impacts our forests and pests and pathogens expand their ranges, understanding the biochemical basis of tree adaptation is critical. My research program addresses fundamental questions in plant biochemistry and physiology, using poplar (Populus) as a model system. The proposed research focuses on the soluble phenolic secondary metabolites that accumulate to extraordinary levels in poplars and many other forest trees. The phenolics are a large family of plant compounds; they include the broadly distributed condensed tannins and other flavonoids, as well as diverse phenolic glycosides and esters. The objective of my research is to investigate how key phenolic compounds are synthesized, how their accumulation is regulated, and how such compounds can help trees adapt to environment stresses. I outline a program of research that covers both biochemical and functional aspects of poplar phenolic metabolism, and which will provide diverse training opportunities. First, we will characterize enzymes and elucidate the biosynthetic pathway for the poplar phenolic glycosides. These compounds, also known as salicinoids, are key anti-insect defenses in poplar and may also have therapeutic potential; however, their biosynthesis is still unknown. Second, we will study the molecular biology and biochemistry of poplar leaf bud resin formation, with the aim of identifying novel enzymes for the biosynthesis of antimicrobial flavonoids and phenolic esters. Third, we will investigate the physiological functions of the condensed tannins, the most widespread phenolic chemicals. We will make use of unique transgenic poplar lines with modified tannin content, and will test a novel hypothesis that condensed tannins function as antioxidants that facilitate efficient nitrogen reallocation during leaf senescence. Fourth, we will test for novel functions of condensed tannins in roots, focusing on their proposed interactions with microbes such as mycorrhizal fungi and pathogens. This will require the generation of new genome-edited transgenic poplars. This research will lead to the discovery of new enzymes, pathways, and functions for several groups of poplar secondary metabolites. It will provide the first molecular analysis of poplar leaf bud resin, known for its bioactive components and for its importance to the ecology of bees. The work will also lead to a deeper understanding of the functions of condensed tannins, and the physiological and ecological roles they play in trees and forests. Our forests produce large quantities of tannins and other phenolics. The impact of these molecules on forest and tree health is of fundamental importance.

树木和森林是加拿大景观和经济的重要组成部分。加拿大的陆地面积占世界森林面积的10%，是一个重要的长期碳汇。因此，森林健康是政策和研究的优先事项。随着气候变化影响我们的森林，害虫和病原体扩大其范围，了解树木适应的生化基础至关重要。我的研究计划解决植物生物化学和生理学的基本问题，使用白杨（杨树）作为模型系统。拟议的研究重点是在杨树和许多其他森林树木中积累到异常水平的可溶性酚类次级代谢产物。酚类化合物是植物化合物的一个大家族;它们包括广泛分布的缩合单宁和其他类黄酮，以及各种酚苷和酯。我的研究目的是研究关键酚类化合物是如何合成的，它们的积累是如何调节的，以及这些化合物如何帮助树木适应环境压力。我概述了一个研究计划，涵盖了白杨酚类代谢的生化和功能方面，这将提供多样化的培训机会。首先，我们将表征酶并阐明白杨酚苷的生物合成途径。这些化合物，也被称为水杨酸，是白杨的关键抗虫防御，也可能具有治疗潜力;然而，它们的生物合成仍然是未知的。其次，我们将研究白杨叶芽树脂形成的分子生物学和生物化学，目的是鉴定用于生物合成抗微生物类黄酮和酚酯的新酶。第三，我们将研究缩合单宁的生理功能，这是最普遍的酚类化学物质。我们将利用独特的转基因白杨品系修改单宁含量，并将测试一个新的假设，即缩合单宁作为抗氧化剂，促进叶片衰老过程中有效的氮再分配的功能。第四，我们将测试缩合单宁在根中的新功能，重点是它们与微生物（如菌根真菌和病原体）的相互作用。这将需要产生新的基因组编辑的转基因杨树。本研究将为白杨次生代谢产物的研究提供新的酶、途径和功能。它将首次对白杨叶芽树脂进行分子分析，该树脂以其生物活性成分和对蜜蜂生态的重要性而闻名。这项工作还将使人们更深入地了解缩合单宁的功能，以及它们在树木和森林中发挥的生理和生态作用。我们的森林产生大量的单宁和其他酚类物质。这些分子对森林和树木健康的影响至关重要。