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

一种合成和分泌生物活性植物天然产物的基因组学方法PI理查德·迪克森，塞缪尔·罗伯茨诺布尔基金会科比·M·大卫·马克斯明尼苏达大学从总体上讲，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。天然产品也构成了许多目前使用的药物的基础，如阿司匹林、吗啡、紫杉醇或抗疟疾化合物青蒿素。植物天然产物通常在分泌毛中合成和积累，分泌毛是植物气生器官上的附属物。毛状体具有独特的化学合成和分泌能力，被描述为生产天然产品的生物工厂。然而，除了少数例外，人们对毛状体代谢和分泌的分子方面知之甚少。在特化的毛状体细胞中生产许多天然产物有助于基于基因组学的方法来表征生物合成和分泌过程。在这个项目中，将产生大量的表达序列标签(EST)，这些基因对应于代表不同植物科和模式植物和农作物的五种植物的毛状体中表达的基因；豆科紫花苜蓿和紫花苜蓿；茄科栽培番茄和番茄；以及啤酒花(Humulus Lupulus)。将对马铃薯叶蝉抗性品系和感病品系进行比较。同时，这五个物种毛状体中产生的天然产物的全谱将被确定。EST文库将挖掘与天然产物的调节、生物合成和运输有关的基因，其中一些多物种共有的基因的功能将通过它们在拟南芥中的过度或低表达来确定。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，为博士后研究员和本科生提供了极好的培训，使他们掌握后基因组时代日益需要的技能。诺布尔基金会和明尼苏达大学将把该项目的主题领域与他们现有的学生外展计划的课程联系起来。该项目的一个主要成果是Trichome，这是一个公开可用的数据库，其中包括植物毛状体中表达的基因和代谢物，这将是对植物基因组序列信息的重要补充，因为只在毛状体中表达的基因可能在非组织靶向的EST测序项目中表达不足。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联系起来。该项目还将提高我们对一系列有用的生物活性天然产物的合成、储存和分泌的了解，从紫花苜蓿中的抗昆虫脂酰胺到啤酒花中有益健康的戊烯基查尔酮和苦味/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.