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不是必需的，但它们被植物用来提供抵抗压力和病原体的保护，吸引传粉者和传播媒介，并作为发育的信号。这些通常被称为“次生代谢物”，但通常被称为植物“天然产物”。天然产品最近被认为是饮食的重要组成部分，可以预防心血管疾病、某些癌症和与年龄有关的退行性疾病。它们也是美容产品和疾病自然疗法的重要组成部分。植物通常会将天然产物积累到相对较低的水平，因此育种或工程植物产生更高水平的兴趣很大。研究表明，增加次生代谢物积累的最有效方法是增加调节产生不同天然产物的生物合成途径活性的基因的活性。这种类型的调节基因编码称为转录因子的蛋白质。利用这一策略培育具有显著高水平重要天然产物的植物的最大瓶颈是，尚未在分子水平上鉴定出许多调节次生代谢的转录因子。本研究旨在鉴定模式植物拟南芥中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测量，这种技术可以识别植物提取物中小有机分子（代谢物）水平的主要差异。这很可能是几个选定的基因编码转录因子具有相同的调控活性。这些基因将被识别，因为增加它们的活性将导致植物代谢产物完全相同的变化。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，以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与质谱定量鉴定相结合来完成。代谢指纹图谱和代谢物图谱的结合将使我们能够识别出控制次生代谢的转录因子编码的新基因，这些基因可以用作工程天然产物积累的工具。该项目还将为植物代谢物谱的广泛鉴定和比较方法的开发做出重要贡献。

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.