苦荞FtMYB17转录因子调控芦丁生物合成途径的分子机制研究

Buckwheat has strong ecological adaptability and abundant nutrients and various flavonoids, such as rutin, quercetin and epicatechin etc., which can function in reducing blood lipid and glucose, anti-bacteria and anti-inflammation. The content of flavonoids in Fagopyrium tatary is much high than the other cultivated buckwheat. Rutin is the main flavonoid in tartary buckwheat, however the regulatory mechanism of rutin biosynthesis still remains unclear. Now, our studies identified an R2R3-MYB transcription factor FtMYB17 that positively regulated the expression of FLS1gene encoding a key enzyme in rutin biosynthesis pathway. Subsequently, our research will combine various techniques of molecular biology, bioinformatics and biochemistry to identify the interacting factors of FtMYB17, to analyze the transcriptional function of FtMYB17, to investigate the tissue specificity of FtMYB17 expression and the stability of FtMYB17 protein, and to demonstrate the function of FtMYB17 in vivo. This work will deeply explain the molecular regulation of rutin biosynthesis mediated by FtMYB17, aiming to provide theoretic knowledge for molecular breeding of high-rutin buckwheat and to increase the economic value of buckwheat.

荞麦生态适应性强，营养全面且富含芦丁、槲皮素、表儿茶素等黄酮类物质，具有降脂、降糖、抑菌及消炎等医疗保健功效。苦荞在所有栽培荞麦中黄酮类物质含量最高，主要以芦丁为主，目前对芦丁生物合成的分子调控机制尚未阐述清楚。通过前期的转录组学和转录活性分析发现，苦荞的R2R3类MYB转录因子FtMYB17正调控芦丁合成途径的关键酶基因FLS1的表达。以此为切入点，本研究拟结合现代分子生物学、生物信息学以及生物化学等手段，分离鉴定FtMYB17的互作蛋白，分析FtMYB17的转录调控功能，探究FtMYB17基因表达的组织特异性及蛋白稳定性，揭示FtMYB17在植物体内功能，全面深入地阐述FtMYB17调控荞麦芦丁代谢途径的分子机制，为高芦丁荞麦的分子育种提供理论基础，提升荞麦利用的经济效益。

荞麦营养物质丰富均衡，尤其是富含其他禾谷类作物所缺乏的芦丁等黄酮类生物活性物质，具有很高的药用价值和保健功效。作为荞麦的起源中心和多样性中心，我国拥有世界上最丰富的野生荞麦资源，也是世界荞麦的主产国之一，但是目前我国栽培荞麦的芦丁含量普遍偏低且不稳定，且芦丁代谢调控机制不明确。因此本项研究通过多组学，鉴定到了一个同时参与芦丁代谢和花青素合成调控的MYB类转录因子FtMYB17。通过质谱鉴定和酵母双杂交，鉴定到了4个与FtMYB17互作的基因，酵母单杂交发现FtMYB17蛋白的C端具有转录激活功能。在FtMYB17基因过表达的毛状根和拟南芥中，PAL、CHS、LAR、ANR、DFR等黄酮类物质代谢通路中的多个关键基因表达量均显著升高，转基因毛状根中芦丁、槲皮素、原花青素等黄酮物质的含量显著升高，且转基因拟南芥的叶片颜色显著加深，呈紫红色。本项目详细阐述了FtMYB17转录因子调控芦丁和原花青素代谢的分子机理，为荞麦分子育种提供了基因资源。另外，通过化学诱变等手段，创建了一系列苦荞突变体材料，创制了高芦丁荞麦新材料“中苦4号”和“中金1号”，培育了高产荞麦新品种“中苦3号”和“川荞8号”，有效的支撑了荞麦育种和产业提质增效。.在本项目的支持下，发表学术论文5篇，其中SCI论文4篇，分别发表在国内外主流植物学和农学杂志Genome Biology、Biotechnology Advances、Critical Reviews in Plant Sciences、Journal of Experimental Botany和作物杂志上，累计影响因子38.59；以第一和第三完成人申请国家发明专利2项；培养硕士研究生1名。