Identification of transcription factors regulating plant secondary metabolism through the integration of functional genomics and metabolomics

植物产生非常广泛的代谢物，这些代谢物对植物细胞的生长并不是必需的，但被植物用来提供对逆境和病原体的保护，吸引传粉者和传播者，并作为发育的信号。这些物质通常被称为“次生代谢物”，但更广为人知的是植物“天然产物”。天然产品最近已被公认为饮食中的重要组成部分，可预防心血管疾病、某些癌症和与年龄相关的退行性疾病。它们也是美容产品和治疗疾病的天然药物的重要组成部分。植物的天然产物通常积累到相对较低的水平，因此人们对培育或设计产生较高水平的植物很感兴趣。已有研究表明，增加次生代谢物积累的最有效方法是提高基因的活性，这些基因调节形成不同天然产物的生物合成途径的活性。这种类型的调控基因编码被称为转录因子的蛋白质。利用这一策略培育积累大量重要天然产物的植物的最大瓶颈是，在分子水平上还没有发现许多调节次生代谢的转录因子。这项提议旨在从模式植物拟南芥中鉴定控制次生代谢不同分支的转录因子。这将通过研究一组可能编码转录因子(从初步证据中确定为可能的调节因子)的选定基因来实现。38个这样的基因中的每一个的活性都将增加，对新陈代谢的影响将通过物理化学技术来衡量，这些技术可以确定植物提取物中有机小分子(代谢物)水平的主要差异。可能有几个选定的基因编码具有相同调节活性的转录因子。这些基因将被识别，因为增加它们的活性将导致植物中代谢产物的完全相同的变化。目的是确定所有具有相同调节活性的蛋白质，然后从每个不同的活性组中选择一个例子来确定该活性丧失对代谢物水平的影响。这将使用灵敏的分离技术和质谱学的定量鉴定来完成。代谢指纹图谱和代谢物图谱的结合应该使我们能够识别编码控制次生代谢的转录因子的新基因，这些基因可以用作设计天然产物积累的工具。该项目还将为开发大范围鉴定和比较植物代谢物图谱的方法做出重要贡献。

Plants produce a very broad array of metabolites, which are not essential for growth of plant cells, but which are used by plants to provide protection against stress and pathogens, to attact pollinators and dispersal agents and as signals for development. These are often referred to as 'secondary metabolites' but are known more generally as plant 'natural products'. Natural products have recently become recognised as important components of the diet, offering protection against cardiovascular diseases, certain cancers and age-related degenerative diseases. They are also important components of beauty products and natural remedies for diseases. Plants often accumulate their natural products to relatively low levels, so there is a lot of interest in breeding or engineering plants that produce higher levels. It has been shown that the most effective way to increase the accumulation of secondary metabolites is to increase the activity of genes that regulate the activity of the biosynthetic pathways that make different natural products. Regulatory genes of this type encode proteins called transcription factors. The biggest bottleneck in using this strategy to develop plants that accumulate significantly higher levels of important natural products is that not many transcription factors regulating secondary metabolism have yet been identified at the molecular level. This proposal aims to identify transcription factors from the model plant, Arabidopsis thaliana, that control different branches of secondary metabolism. This will be achieved by studying a selected group of genes that probably encode transcription factors (identified from preliminary evidence as likely regulators). The activity of each of 38 such genes will be increased and the effects on metabolism will be measured by physico-chemical techniques that can identify major differences in the levels of small organic molecules (metabolites) within plant extracts. It is likely that several of the selected genes encode transcription factors that have the same regulatory activity. These genes will be identified because increasing their activity will result in exactly the same changes in metabolites in plants. The aim will be to identify all the proteins that have the same regulatory activities and then to choose one example from each distinct activity group to establish the effects of loss of that activity on metabolite levels. This will be done using sensitive techniques of separation coupled with quantitative identification by mass spectrometry. The combination of metabolic fingerprinting and metabolite profiling should allow us to identify new genes encoding transcription factors controlling secondary metabolism that can be used as tools for engineering natural product accumulation. This project will also make an important contribution to method development for broad range identification and comparison of metabolite profiles in plants.