调控火龙果甜菜素生物合成核心MYB转录因子的筛选、鉴定及机制解析

火龙果是重要的热带水果，其营养丰富，含有一般植物少有的甜菜素，也是唯一富含甜菜素的水果，因而是研究甜菜素的良好材料。火龙果果皮和果肉呈现不同颜色主要来源于甜菜素的合成和积累不一样。目前，甜菜素的生物合成途径已在甜菜和苋菜等植物中进行了广泛研究，其生物合成途径中的结构基因已经阐明得比较清楚，但关于甜菜素生物合成的调控机制尚不清楚。在前期研究中，我们通过对火龙果的转录组分析，初步获得了两个与火龙果甜菜素相关的MYB调控因子HpMYB39和HpMYB-like，本项目拟以MYB调控因子为切入点，采用生物信息学、时空表达、亚细胞定位、酵母双杂、BiFC、VIGS、转基因等方法进一步挖掘与火龙果甜菜素生物合成相关的MYB核心成员，并对其功能进行解析，阐明MYB转录因子调控火龙果甜菜素生物合成的分子机制，完善植物甜菜素生物合成的调控机制，为火龙果果实色泽调控及外观品质的改良提供理论依据。

Dragon fruit is an important tropical fruit with rich nutrients and betalains. Dragon fruit is the only fruit containing abundant betalains for consumer which is rare in plants. It is a good material for studying betalain biosynthesis. The difference of peel and pulp color in dragon fruit are mainly derived from the synthesis and accumulation of betalains. At present, the biosynthetic pathway of betalain has been extensively studied in model plants such as Beta vulgaris and Amaranthus tricolor. The structural genes involved in betalain biosynthetic pathway have been elucidated clearly. However, regulatory factors involved in betalain biosynthesis are still not clear. In previous studies, we obtained two MYB regulatory factors i.e. HpMYB39 and HpMYB-like involved in betalain biosynthesis based on analyses of transcriptome data. In this study, bioinformatics, space-time expression, subcellular localization, yeast two hybrid, bimolecular fluorescence complementation (BiFC), virus-induced gene silencing (VIGS) and genetic transformation will be used to further screen key MYB regulatory factors involved in betalain biosynthesis of dragon fruit. Furthermore, their function will be verified. The study will elucidate the molecular mechanism underlying the regulation of betalain biosynthesis. The present results could help to understand the regulation mechanism of betalain biosynthesis in plants and provide a theoretical basis for the color improvement of dragon fruit.