斑叶草CYC类基因启动子控制两侧对称花形成的调控功能研究

Zygomorphic flower evolved from an actinomorphic ancestor, where it likely facilitated species diversification through adaptation to insect pollination. Investigations throughout angiosperms show that zygomorphy is controlled by CYC-like genes. It is necessary for CYC-like genes to maintain their expression in developing flowers to establish the zygomorphic morphology. The CYC binding sites found in promoters of CYC-like genes provide an interpretation for the dosalized sustainable expression of CYC-like genes in zygomorphic lineages. However, how is the dorsal-specific expression pattern estabalished for CYC-like genes? What cis-elements or trans-factors are CYC-like genes acted on for their dorsal-specific expression? All of these question remain unresolved now..Gesneriaceae is the basal family of Lamiales s.l., with primitive and diverse forms of bilateral symmetry flowers. It is therefore an interesting family from the point of view of the evolution of floral symmetry and their regulatory mechanism. Chirita pumila, with zygomorphic flower, has established efficient transgenic system which making it an ideal system to study the molecular regulatory mechanisms of related genes. Here, we selecte C. pumila as materials for the study of transcriptional regulatory mechanism of CYC-like genes through transgenic technology..Last，we would clarify the mechanism of dorsal-specific CYC-like genes expression pattern at transcriptional level and the function of some cis-regulatory factors in controlling zygomophic development.

两侧对称花被认为由辐射对称花进化而来，并通过对传粉者的适应促进了物种多样性。大量研究表明，在被子植物范围内CYCLOIDEA(CYC)类基因广泛参与了两侧对称花的形成。CYC类基因的背特性持续表达是两侧对称花形成的关键。已有的研究已经揭示，CYC结合位点的进化保证了其表达的持续性。但是，CYC类基因背特性的表达模式是如何实现的，可能受到哪些顺式和反式因子的调控等问题至今还仍未解决。.苦苣苔科隶属于广义唇形目，具有丰富而原始的两侧对称花类群，是研究两侧对称花形成机制的理想类群。该科的斑叶草具有典型的两侧对称花，并建立了成熟的转基因体系，为控制两侧对称花发育相关基因的调控机制研究提供了有力保障。本项目拟以斑叶草为材料利用转基因手段在转录调控方面全面开展CYC类基因控制两侧对称花形成的调控功能研究，揭示CYC类基因时空特异性表达的转录调控机制和关键调控因子在控制斑叶草两侧对称花形成中的功能。

本项目以苦苣苔科的斑叶草为研究材料开展了控制花对称性的CYC类基因的转录调控机制研究。首先对斑叶草中CYC类基因在花发育早期的表达模式与CpCYC基因启动子启动的GUS报告基因表达模式展开了比较研究，最终确定控制CpCYC1和CPCYC2基因特异性表达模式的关键启动子调控区段，并总结出了其实现特异性表达模式的调控方式。然后，通过对CpCYC基因启动子进行的精细片段截短分析，分别确定了控制CpCYC基因在不同区域表达的最小调控区域及其功能。最后经DNA-蛋白互作分析结合元件的瞬时表达活性分析确定元件的保守序列和边界。最终我们鉴定到了控制CpCYC基因特异性表达的三个已知转录因子的结合元件和一个具有抑制活性的新元件。经全面的综合分析，本项目以期揭示斑叶草两侧对称花形成的调控机制。该项目研究结果对进一步理解两侧对称花形成的分子机理和进化机制具有重要的理论意义。