花椰菜花球发育调控相关基因CDAG1的功能及调控机制研究

Curd is a specialized organ of cauliflower (Brassica oleracea L. var. botrytis), which is resulted by overproliferation of inflorescence meristem. The formation of curd is the most remarkable trait that differentiates cauliflower from other crucifers. Moreover, curd is the most important edible organ of cauliflower.Then the quality and yield of curd is crucial for the economic value of cauliflower. However, the formation and development of cauliflower curd is still poorly understood. In our previous study,a novel gene, named CDAG1(Curd Development Associated Gene 1) was first cloned by our team. The function analysis of this gene in Arabidopsis showed that overexpression of CDAG1 can make the transgenic Arabidopsis display more flowering branches and flower buds, stronger roots, improved biomass. Moreover, overexpression of CDAG1 in cauliflower also indicated that the overexpression of CDAG1 can significantly improve the cauliflower organ development. Theses results implied that the important roles of CDAG1 in regulationg plant development. In the present study, several methods such as transcriptome analysis, Co-Immunoprecipitation (Co-IP) Mass spectrometer, Protoplast transformation, Yeast two hybrid and RNAi were used to further identify the genes regulated by CDAG1, and the key factors interacted with CDAG1. Following that the function of the genes and factors should be elucidated, and the final subject of the study is to elucidate the roles of CDAG1 in regulating the formation of curd in cauliflower from the molecular level. The findings should give new insights into the nature basis of organ development in cauliflower.

花球是花椰菜区别其他十字花科植物，由花序分生组织构成的特化器官，也是花椰菜唯一的产品器官，直接决定其经济价值。但对花椰菜花球形成及发育机制的认识仍很有限。我们前期克隆到一个在花椰菜器官发育，特别是花球发育中发挥重要作用的新基因，命名为CDAG1。研究表明，在拟南芥中过表达CDAG1可使转基因拟南芥花枝及花蕾数目显著增多、根系更加发达、生物量显著提高。该基因在花椰菜自身中的过表达分析也表明，CDAG1过表达可显著促进花椰菜的器官发育。但CDAG1的功能仍有待阐释。本项目拟采用转录组分析、Co-IP结合质谱分析、原生质体瞬时表达结合酵母双杂交分析、RNAi分析等多种方法进一步对参与CDAG1调控路径的关键基因、与CDAG1发挥协同调控作用的关键因子进行鉴定、克隆，进而揭示他们的功能，最终阐释CDAG1在花椰菜花球发育过程中的分子功能和调控特征。研究对揭示花椰菜器官发育的分子基础具有重要意义。

在生殖发育过程中形成由花序分生组织构成的花球是花椰菜区别于其他十字花科植物的最主要特征。花球也是花椰菜唯一的产品器官，直接决定花椰菜的经济价值。但长期以来对花椰菜花球的形成及其在后期发育过程中调控机制认识十分有限。CDAG1（Curd Development Associated Gene 1）是一个从花椰菜中分离到的与花球发育相关的基因，其功能未知，为首次报道。为此，项目对CDAG1的基因结构及其在花椰菜中的表达特征、功能及其调控特征进行了深入探究。研究表明，CDAG1在花椰菜不同组织中表现为显著差异表达，其中在幼嫩分生组织中表现为高表达。在拟南芥及花椰菜中过表达CDAG1可显著提高转基因株系的生物量，特别是可使花椰菜花球产量提高30%。细胞学分析表现，CDAG1可通过对细胞数目和细胞大小的正向调控而在高产量性状形成过程中发挥重要作用。进一步研究证实，CDAG1可能参与了乙烯介导的调控路径。相关研究为进一步揭示CDAG1在花椰菜器官发育，特别是花球发育中的功能奠定了坚实基础,并为高产作物及经济植物基因工程育种提供了优质基因资源。依托本项目已发表SCI论文（IF>3.0）3篇，核心期刊论文1篇，申请专利2项，培养3名研究生。