本项目拟在苦苣苔科选择斑叶草和大岩桐作为模式体系，开展CYC类基因控制花朝向的分子调控和进化机制研究。我们首先进行CYC类基因启动子系列截短的转基因GUS信号分析，确定其具有控制花朝向转录活性的启动子最小区段；经过对启动子最小区段系列碱基替代的定点突变分析和候选元件的获得性功能分析，揭示CYC类基因作用于花朝向的顺式调控元件。然后，利用顶向朝向辐射对称花突变体，我们进一步开展全长启动子转基因互补性功能分析，最终确定这些被揭示的花朝向顺式调控元件的形态功能。在上述研究基础上，通过在斑叶草、大岩桐以及相关类群之间的比较和综合分析，本项目预期全面揭示CYC类基因对花朝向的调控过程及其分子进化机制。该项目对全面了解CYC类基因的功能以及被子植物花适应性进化的分子机制具有重要理论意义。

This project will select Chirita pumila and Sinningia speciosa as a pair of model systems to explore the molecular regulation and evolutionary mechanism of CYC-like genes in controlling floral orientation in Gesenriaceae. First, we conduct a series of deletion analyses in the 5’ regulatory region of CpCYC and SsCYC genes transformed with GUS reporter gene, respectively, aiming to recognize the minimal promoters controlling floral orientation. Then, we perform a series of analyses of substitution mutations in candidate minimal promoters to determine the cis-elements specific for the floral orientation. We further carry out transgenic gain-of-function and functional complement tests of the detected cis-elements related to CYC-like gene specific transcription and function in controlling floral orientation in Chirita pumila and Sinningia speciosa. Furthermore, this project will conduct comparative analyses in the regulatory regions of CpCYC and SsCYC genes, including putative variation in related position and DNA sequence of cis-elements, and comprehensive analyses of molecular-phenotypic evolution of floral orientation between the two model systems, to reveal the regulation process and molecular evolutionary mechanism of CYC-like genes in controlling floral orientation. This project is significant in fully understanding the function of CYC-like genes, providing insight into the molecular mechanism underlying the floral adaptive evolution in angiosperms.