Collaborative Research: Integration of Glandular Trichome Metabolism and Development by a Flavonoid Pathway Signal

毛状体是一种特殊的表皮细胞，存在于大多数植物中，可以优化化合物的生产，从而保护植物免受环境的侵害。人们对这些表皮“生物工厂”的广泛兴趣因许多腺体来源的物质可用于工业和医疗目的而增强。尽管对腺毛的代谢“部件表”的编目已经取得了重大进展，但有关毛结构内部代谢调控和发育的基本问题仍有待解答。为了与毛状腺作为生化工厂的类比保持一致，该项目试图解决与这种高度进化结构的操作原理有关的两个主要问题：工厂内各种装配线（代谢途径）如何协调，以及对组装产品（生物活性化合物）需求的变化如何影响工厂的构建方式？该研究有可能通过推进看似不同的代谢途径之间交叉调节的概念，并确定已被充分表征的酶的新作用，来改变目前对代谢的看法。腺状毛状体产生多种生物活性化合物，保护地上植物组织免受生物和非生物胁迫。毛状腺的代谢活动通常由萜类和类黄酮的产生所主导，这两种化合物是自然界中最多样化和经济上最重要的两类化合物。阐明这些和其他次生代谢物的生物合成途径的进展远远超过了理解发育细胞类型和结构的努力，这些细胞类型和结构通常是防御化学物质生物功能的关键。最近的研究表明，番茄腺毛中萜类和类黄酮的生物合成与腺体发育是偶联的，有趣的是，它们受到类黄酮生物合成酶查尔酮异构酶（CHI）的协同影响。该项目的总体目标是结合实验和数学建模方法，以实现对毛状体代谢和发育过程如何集成的系统级理解。实验方法是基于使用纯化的毛状腺（单细胞类型）进行转录组学，蛋白质组学和代谢组学分析，以及强大的遗传工具来操纵影响腺体发育和代谢的功能过程。该研究还可能揭示一种已被充分研究的代谢酶（CHI）的新作用，并拓宽目前对小分子如何控制代谢的看法。该项目为来自不同背景的学员提供多学科培训机会，包括参与植物基因组学REU暑期研究计划的本科生。该项目将通过与密歇根州立大学园艺花园和当地工业的合作，增加公众对科学的不同部分的访问。项目科学家将与4-H儿童花园、当地小学、薄荷和其他芳香植物的商业种植者合作，为儿童提供实践学习经验，说明毛状体衍生化合物在植物生物学中的重要性。

Trichomes are specialized epidermal cells present in most plants that optimize the production of compounds that provide protection against environmental insults. Broad interest in these epidermal "biofactories" is heightened by the fact that many gland-derived substances are useful for industrial and medicinal purposes. Although significant progress has been made in cataloging the metabolic "parts list" of glandular trichomes, fundamental questions concerning the regulation of metabolism within, and development of, the trichome structure remain to be answered. In keeping with the analogy of the trichome gland as a biochemical factory, this project seeks to address two major questions concerning the operating principles of this highly evolved structure: how are various assembly lines (metabolic pathways) within the factory coordinated, and how do changes in the demand for the assembled products (bioactive compounds) influence the way in which the factory is constructed? The research has potential to transform current views of metabolism by advancing the concept of cross regulation between seemingly disparate metabolic pathways, and defining new roles for well characterized enzymes. Glandular trichomes produce a wide variety of bioactive compounds that protect aerial plant tissues from biotic and abiotic stress. The metabolic activity of trichome glands is often dominated by the production of terpenoids and flavonoids, which comprise two of the most diverse and economically important classes of compounds in nature. Progress in elucidating biosynthetic pathways for these and other secondary metabolites has far outpaced efforts to understand the developmental cell types and structures that are often key to the biological function of defense chemicals. This research project builds on recent studies showing that terpenoid and flavonoid biosynthesis in glandular trichomes of tomato is coupled to gland development and, intriguingly, is coordinately impacted by the action of the flavonoid biosynthesis enzyme chalcone isomerase (CHI). The broad objective of the project is to combine experimental and mathematical modeling approaches to achieve a systems-level understanding of how trichome metabolic and developmental processes are integrated. The experimental approaches are grounded in the use of purified trichome glands (a single cell type) for transcriptomic, proteomic, and metabolomic analyses, as well as powerful genetic tools to manipulate functional processes affecting gland development and metabolism. The research may also reveal new roles for a well-studied metabolic enzyme (CHI) and broaden current views of how small molecules control metabolism. The project provides multi-disciplinary training opportunities for trainees from diverse backgrounds, including participation of undergraduate students in the Plant Genomics REU Summer Research Program. The project will increase access by diverse segments of the public to science through partnerships with the MSU Horticulture Gardens and local industry. Project scientists will partner with the 4-H Children's Garden, local elementary schools, and commercial growers of mint and other aromatic plants to provide children with hands-on learning experiences that illustrate the importance of trichome-derived compounds in plant biology.