重瓣性是园林植物的主要观赏性状，然而在重要园林观赏植物矮牵牛中，有关其花器官数目控制的分子调控机理还很不明晰。本项目以矮牵牛C类基因，PMADS3与FBP6这两个矮牵牛重瓣形成的核心C类基因为立足点，利用酵母单、双杂交和染色质免疫共沉淀测序(ChIP-Seq)等技术，对其上下游基因和水平互作因子进行大规模筛选。在对筛选结果进行多角度验证的基础上，利用超量表达和RNAi技术构建矮牵牛相关单、双突变体，并结合课题组前期工作中保存的自然重瓣、花瓣变异突变体以及转基因获得的雄蕊瓣化、花器官增多、花分生组织延迟终止或不中止株系等材料，对矮牵牛单重瓣形成的分子基础进行全面剖析，以阐明矮牵牛C类基因在单重瓣性状形成过程中的功能定位和调控网络。本项目的实施，不仅可以深入解析重瓣矮牵牛形成的分子机制，丰富目前的花发育理论，并且在实施过程中有望实现人工重瓣花。

Double flowered trait is the main ornamental character of landscape plants. It is known that ABCDE model and AG/WUS feedback loop play a vital role in the flower development of the model plant -- Arabidopsis thaliana. However, the molecular mechanism which regulates the flower organ number in Petunia Hybrida, one of major landscape plants, still remains obscure. Based on the research of type C genes - PMADS3 and FBP6 that control the formation of double flower in petunia, our project will use yeast one-hybrid and two-hybrid systems, chromatin immunoprecipitation sequencing and some other techniques to screen C genes' upstream and downstream genes, and their horizontal interaction factors on a large scale. In order to illustrate the function and regulatory network of C genes in the formation of petunia's double flower, after the multiple confirmation of the result, we will fully analyze the molecular mechanism of the double flower's formation in Petunia with our materials including 1) transgenic petunia mutants, obtained by the transformation with overexpression and RNAi vectors; 2) wide petunia mutants, presenting characteristics of natural double flowered and natural mutations in petal. The implementation of our project will not only analyze the molecular mechanism of petunia's double flower's formation deeply, then enrich the theory of flower development, but also acquire man-made double flower petunia.