Comparative Genomics of Secretory Trichomes - Biofactories for Production of Plant Secondary Metabolites

生物活性植物天然产物合成和分泌的基因组学方法PI Richard狄克逊，Samuel Roberts Noble Foundation coPI M.大卫马克斯明尼苏达大学总的来说，植物是天然产物的丰富来源，这些化学物质通常起到保护植物免受感染或虫害的作用。天然产品也是目前使用的许多药物的基础，如阿司匹林、吗啡、紫杉醇或抗疟化合物青蒿素。分泌毛是植物地上器官上的附属物，是植物天然产物合成和积累的主要途径。毛状体具有独特的化学合成和分泌能力，并被描述为生产天然产物的生物工厂。然而，除了少数例外，对毛状体代谢和分泌的分子方面知之甚少。许多天然产物在特化的毛状体细胞中的产生促进了基于基因组学的方法来表征生物合成和分泌过程。本项目将对代表不同植物科的5个物种、模式植物和农作物的毛状体中表达的基因进行大量的表达序列标签（EST）。sativa（苜蓿），豆科植物; Nicotiana benthamiana和Lycopersicum esculentum（栽培番茄），茄科;和啤酒花（啤酒花）。将比较抗马铃薯叶蝉和感马铃薯叶蝉的苜蓿品系。同时，将确定这五个物种的毛状体中产生的天然产物的全谱。该项目将从EST库中挖掘与天然产物的调控、生物合成和运输有关的基因，并通过在拟南芥中过度表达或表达不足来确定多个物种共有的基因的功能。该项目是多学科的，将基因组学、信息学和分子生物学与分析生物化学、酶学和代谢工程相结合，并为博士后研究员和本科生提供在后基因组时代日益需要的技能方面的出色培训。诺贝尔基金会和明尼苏达大学将把该项目的主题领域与其现有的学生外联方案的课程联系起来。该项目的一个主要成果是TrichOME，这是一个公开的植物毛状体中表达的基因和代谢物数据库，将是植物基因组序列信息的重要补充，因为仅在毛状体中表达的基因可能在非组织靶向EST测序项目中代表性不足。随着项目的发展，数据库中的基因序列将与描述基因参与毛状体特定过程的功能信息相关联。该项目还将提高我们对一系列有用的生物活性天然产品的合成，储存和分泌的理解，从苜蓿中的抗昆虫脂质酰胺到对健康有益的异戊二烯基查耳酮和啤酒花中的苦味酸香料/抗菌剂。

A genomics approach to the synthesis and secretion of bioactive plant natural productsPI Richard Dixon, Samuel Roberts Noble Foundation coPI M. David Marks University of MinnesotaCollectively, plants are a rich source of natural products, chemicals that often function to protect the plant from infection or insect pests. Natural products also form the basis of many currently used drugs, such as aspirin, morphine, taxol or the antimalarial compound artemesinin. Plant natural products are often synthesized and accumulated in secretory trichomes, which are appendages found on the aerial organs of plants. Trichomes have a unique capacity for chemical synthesis and secretion, and have been described as biofactories for the production of natural products. However, with few exceptions, little is known about the molecular aspects of trichome metabolism and secretion. The production of many natural products in specialized trichome cells facilitates genomics-based approaches to characterize biosynthetic and secretory processess. In this project, a large number of expressed sequence tags (ESTs) will be generated corresponding to genes expressed in trichomes of five species representing different plant families and both model and crop plants; Medicago truncatula and M. sativa (alfalfa), Leguminosae; Nicotiana benthamiana and Lycopersicum esculentum (cultivated tomato), Solanaceae; and hops (Humulus lupulus). Potato leafhopper resistant and susceptible alfalfa lines will be compared. At the same time, the full spectrum of natural products produced in the trichomes of these five species will be determined. The EST collection will be mined for genes involved in the regulation, biosynthesis and transport of natural products, and the functions of a selection of those genes that are common to multiple species will be determined by over- or under-expressing them in Arabidopsis thaliana.The project is multidisciplinary, combining genomics, informatics and molecular biology with analytical biochemistry, enzymology, and metabolic engineering, and provides excellent training for postdoctoral fellows and undergraduate students in the skills increasingly required in the post-genomics age. The Noble Foundation and University of Minnesota will link the subject area of the project to the curricula of their existing student outreach programs. A major deliverable of the project, TrichOME, a publicly available database of genes and metabolites expressed in plant trichomes, will be an important addition to plant genome sequence information, as genes only expressed in trichomes may be under-represented in non-tissue-targeted EST sequencing projects. As the project develops, gene sequences in the database will be linked to functional information describing the involvement of the genes in trichome-specific processes. The project will also improve our understanding of the synthesis, storage and secretion of a range of useful bioactive natural products, from anti-insect lipid amides in alfalfa to heath-beneficial prenyl chalcones and bitter acid flavors/antimicrobials in hops.