蓝色瓜叶菊中多聚酰化花青素生物合成及调控机制研究

含有多个糖基和芳香酰基的多聚酰化花青素能够使植物花朵呈现明亮和稳定的蓝色，但参与多聚酰化基因的分离和功能研究很少，限制了纯正蓝色花的分子育种。瓜叶菊是重要的盆栽观赏植物，其蓝色花中含有罕见的3'和7位同时具有聚酰集团的飞燕草色素苷，暗示其蕴藏丰富的蓝色花育种基因资源。前期研究表明糖基转移酶家族的ScU3'GT、ScU7GT和丝氨酸羧肽酶家族的ScSCPL1、2在蓝色花中高丰度特异性表达，沉默4个基因使瓜叶菊蓝色褪色或变为洋红色。本项目拟继续通过瓜叶菊舌状花中的基因沉默、转基因（烟草和本源植物），结合质谱分析上述基因在聚酰化花青素生物合成中的功能；利用体外酶促反应和底物特异性分析研究其聚酰化修饰特性和修饰位点；通过分子生物学和生化技术研究上游转录因子对关键基因的调控，最终解析蓝色瓜叶菊中多聚酰化花青素生物合成的分子机理，项目对于高等植物蓝色花呈色及分子育种均具有重要意义。

Polyacylated anthocyanins with multiple glycosyl and aromatic acyl groups tends to make flowers display bright and stable blue color. However, there are few studies on the isolation and functional characterization of genes involved in polyacylated anthocyanins biosynthesis mechanism, which limits the molecular breeding of truly blue flowers. Senecio cruentus is an important potted ornamental plant, and its blue flowers contain 3',7-polyacylated delphinidin-type anthocyanins which was not reported in any other plants, suggesting that it harbors abundant gene resources for the breeding of blue flowers. Our previous studies have shown that the ScU3'GT, ScU7GT belonged to uridine diphosphate glycosyltransferase family and the ScSCPL1, 2 belonged to serine carboxypeptidase-like family were specifically expressed at high levels in blue flowers, and silencing these four genes made the blue color of both leaves and capitulum fade or turn carmine. In this study, we will identify the function of these genes involved in biosynthesis of polyacylated anthocyanins through gene silencing in ray flowers of S. cruentus, transformating target gene into tobacco and native plants respectively and carring out the LC-MS/MS analysis. In vitro enzymatic reaction will be used to analyze the substrate specificity and modification sites of candidate modification genes. The regulatory mechanism of key structural genes by upstream transcription factors will be studied through molecular biology and biochemical techniques. The expected results of this project will providing new insight into the molecular basis of polyacylated anthocyanin biosynthesis mechanism in higher plants and of great significance for blue flower molecular breeding of ornamental plants.