Engineering of Plant One-carbon Metabolism for Folate and Methionine Accumulation

叶酸和蛋氨酸积累的植物一碳代谢工程

• 批准号: 0429968
• 负责人: Sanja Roje
• 金额: --
• 依托单位: Washington State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-01-01 至 2010-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0429968&HistoricalAwards=false
• 关键词: Engineering; Plant; carbon; Metabolism; Folate

The aim of this project is to develop strategies for metabolic engineering of plants enriched in folates and soluble methionine by manipulating the network of tetrahydrofolate-bound one-carbon (C1) units in plastids. Plants will be engineered to consist of simultaneous expression of methionine synthase and 5,10-methylenetetrahydrofolate enzymes in plastids. Two methods for over-expression will be tested: chloroplast-targeted expression from strong constitutive nuclear gene promoters, and ectopic expression from the genes incorporated into the plastid genome. Metabolic engineering will be carried out in tobacco (Nicotiana tabacum), a species in which plastid transformation can be routinely obtained. Isozymes of serine hydroxymethyltransferase (SHMT) will also be studied, as this enzyme may be a rate-limiting step of folate biosynthesis. Understanding the biochemical properties and subcellular localization of SHMT is essential for planning and interpretation of the proposed metabolic engineering experiments, a study that will be carried out in Arabidopsis thaliana, a model species in plant biology, in which genomic resources are available. The research can lead to the generation of plants enriched in folates and methionine. Folate deficiency in humans has been linked to anemia, birth defects and vascular diseases. Engineered plants with increased folate content will represent a dietary source of natural folates, and could potentially solve the problem of poor folate uptake, and the associated health disorders, for human populations. Methionine is an essential amino acid for humans and nonruminant animals. Crops used for animal feed do not have optimal methionine content, so they must be fortified with supplemental methionine. The high cost of this supplementation has prompted recent interest in metabolic engineering of plants with increased methionine content. The research program, in collaboration with Dr. Pal Maliga at Rutgers University, will train students and post-doctorals in all aspects of metabolic engineering.

该项目的目的是通过操纵质体中四氢叶酸结合的一碳（C1）单元的网络，开发富含叶酸和可溶性蛋氨酸的植物的代谢工程策略。 植物将被改造成由在质体中同时表达甲硫氨酸合酶和5，10-亚甲基四氢叶酸酶组成。将测试两种过表达方法：从强组成型核基因启动子的叶绿体靶向表达，以及从并入质体基因组的基因的异位表达。代谢工程将在烟草（Nicotiana tabacum）中进行，烟草是一种可以常规获得质体转化的物种。丝氨酸羟甲基转移酶（SHMT）的同工酶也将进行研究，因为这种酶可能是叶酸生物合成的限速步骤。了解SHMT的生化特性和亚细胞定位对于规划和解释拟议的代谢工程实验是必不可少的，这项研究将在植物生物学的模式物种拟南芥中进行，其中基因组资源是可用的。 这项研究可能导致富含叶酸和蛋氨酸的植物的产生。人类叶酸缺乏与贫血、出生缺陷和血管疾病有关。叶酸含量增加的工程植物将代表天然叶酸的膳食来源，并可能解决人类叶酸摄取不足和相关健康疾病的问题。蛋氨酸是人类和非反刍动物的必需氨基酸。用于动物饲料的作物没有最佳的蛋氨酸含量，因此必须用补充蛋氨酸强化。这种补充剂的高成本促使最近对具有增加的甲硫氨酸含量的植物的代谢工程的兴趣。该研究计划与罗格斯大学的Dr. Rutgers合作，将在代谢工程的各个方面对学生和博士后进行培训。