Primulina genus is an ideal wild ornamental flower and emerging model for studying biosynthesis, diversity, and evolution of flower pigment. However, the molecular mechanism underlying anthocyanin biosynthesis and regulation in Primulina remains unknown. Here, changes in anthocyanin content and the expression profiles of anthocyanin biosynthetic structural genes were examined in developing Primulina swinglei flowers and three other organs. Seventy-three R2R3-MYB transcription factor genes were identified from transcriptome of P. swinglei flowers, two of which, PsMYB1 and PsMYB2, are candidate regulators of anthocyanin biosynthesis according to clustering analysis. Furthermore, transient over-expression studies using tobacco leaves showed distinct pigment accumulation following co-infection with PsMYB1 and MrbHLH1 (a previously confirmed anthocyanin regulator from Morella rubra). Additionally, dual luciferase assays showed that PsMYB1 trans-activated the PsANS promoter, with the addition of MrbHLH1 resulting in a 5-fold increase in the intensity of this interaction. PsMYB1 did not, however, have any effect on the PsF3H promoter. The expression profile and dual luciferase assays showed that PsMYB2 plays no roles in anthocyanin regulation. Therefore, PsMYB1 is proposed to be the transcription factor gene regulating anthocyanin biosynthesis in P. swinglei.

中文翻译：

---

R2R3-MYB转录因子的鉴定涉及调节樱草花中花色苷的生物合成。

报春花属是理想的野生观赏花和新兴模型，用于研究花色素的生物合成，多样性和进化。但是，报春花中花色苷生物合成和调控的分子机制仍然未知。在这里，在发育的报春花和其他三个器官中检查了花色苷含量的变化和花色苷生物合成结构基因的表达谱。根据聚类分析，从秋千花的转录组中鉴定出73个R2R3-MYB转录因子基因，其中两个PsMYB1和PsMYB2是花色苷生物合成的候选调节剂。此外，使用烟草叶片的瞬时过表达研究表明，在与PsMYB1和MrbHLH1（先前已确认的来自Morella rubra的花色苷调节剂）共感染后，明显的色素积聚。此外，双重荧光素酶测定法显示，PsMYB1反式激活了PsANS启动子，添加了MrbHLH1，导致这种相互作用的强度增加了5倍。但是，PsMYB1对PsF3H启动子没有任何影响。表达谱和双重荧光素酶测定表明，PsMYB2在花色苷调节中不起作用。因此，PsMYB1被认为是调控秋千花青素生物合成的转录因子基因。加上MrbHLH1会导致这种相互作用的强度增加5倍。但是，PsMYB1对PsF3H启动子没有任何影响。表达谱和双重荧光素酶测定表明PsMYB2在花色苷调节中不起作用。因此，PsMYB1被认为是调控秋千花青素生物合成的转录因子基因。加上MrbHLH1会导致这种相互作用的强度增加5倍。但是，PsMYB1对PsF3H启动子没有任何影响。表达谱和双重荧光素酶测定表明PsMYB2在花色苷调节中不起作用。因此，PsMYB1被认为是调控秋千花青素生物合成的转录因子基因。