毛茛科中花瓣缺失的分子机制研究

项目名称： 毛茛科中花瓣缺失的分子机制研究

项目编号： No.31300196

项目类型： 青年科学基金项目

立项/批准年度： 2014

项目学科： 生物科学

项目作者： 国春策

作者单位： 中国科学院植物研究所

项目金额： 24万元

中文摘要： 花瓣通常是花中最显眼的器官，起到吸引传粉者的作用。但是，有些植物（包括被子植物中一些比较大的分支，如胡椒科、檀香科、桑科、榆科和壳斗科等）在进化的过程中丢失了花瓣，产生了无瓣花。导致花瓣丢失的遗传和分子机制尚不清楚，但在毛茛科中被发现与APETALA3-3（简称AP3-3）基因的不表达或者低表达密切相关。我们前期的研究发现尽管AP3-3的沉默能够导致花瓣的缺失，但其表型与野生的无花瓣物种有明显不同。通过分析，我们认为导致花瓣缺失的根本原因并不是AP3-3的沉默或者下调，而是AGAMOUS1（简称AG1）基因表达范围的外扩。据此，我们提出了一个可以验证的工作模型。本项目拟在已有工作的基础上，设计实验验证这个模型，揭示毛茛科中花瓣缺失的分子机制，探讨花瓣在毛茛科及其他类群中多次丢失的遗传基础和适应意义。由于涉及到对相关调控元件的鉴定和功能分析，本项目属于调控进化的范畴，有望取得创新性研究结果。

中文关键词： 毛茛科；花瓣缺失；MADS-box基因；平行进化；分子机制

英文摘要： Petals are usually the showiest organs of a flower with dimorphic perianth, and function to attract pollinators. Nevertheless, there are plant groups (including several species-rich lineages of angiosperms, such as the Piperaceae, Santalaceae, Moraceae, Ulmaceae, and Fagaceae) in which petals no longer exist, so that the flowers become apetalous. The mechanisms underlying petal losses are still unclear, yet it has been indicated that the parallel petal losses within the buttercup family (Ranunculaceae) are strongly correlated with decreased or eliminated expression of the APETALA3-3 (AP3-3) gene. Our own study, instead, showed that while silencing of AP3-3 can indeed lead to the loss of petals, it actually generated a phenotype that is different from those of naturally occurring apetalous species. Based on this observation, we argued that expansion of another gene, AGAMOUS1 (AG1), rather than inactivation or down-regulation of AP3-3 itself, was the real cause for parallel petal losses in naturally occurring apetalous species. A work model was therefore proposed to explain the genetic basis for the process. In this project, we propose to conduct a series of experiments to test whether our work model is correct, to uncover the molecular basis for parallel petal losses within the Ranunculaceae, and to shed light on

英文关键词： Ranunculaceae；petal losses；MADS-box genes；parallel evolution；molecular mechanism