叶片是植物光合作用的主要器官，叶片形态和大小对植物本身适应环境很重要，也直接影响农作物的产量，因此研究叶片发育的关键保守机制具有重要现实和理论意义。顶枝理论认为叶片由侧枝进化而来，申请人通过正向遗传学筛选并分析叶片和侧枝均有缺陷的突变体，系统地研究了控制叶片发育的关键转录调控机制。发现了调控叶片发育的重要转录抑制机制；阐明了降解调控机制与转录抑制机制协同精确调控叶片发育；找到了控制叶片发育和侧枝形成的关键转录激活因子。这些发现揭示了叶片发育的重要保守新机制，成果分别发表在Plant Cell、PNAS、Cell Res、New Phytol等国际主流期刊上。本项目拟在以上工作的基础上，进一步鉴定调控叶片发育的新基因，完善叶片发育的保守分子调控网络，为作物分子设计育种提供必要的基因资源和理论依据。

Plant leaves are the main organs for photosynthesis. The final leaf size and morphology are not only important for plant survival but also affect crop yields. Thus, it has both theoretic and practical significances to identify the grand conserved molecular mechanisms in leaf development. The “telome theory” suggests that leaves evolved from lateral branches. To identify the conserved mechanisms in control of leaf development, I screened and analyzed the mutants defective in both leaves and branches using forward genetics. I systemically elucidated the key and conserved transcription regulation mechanisms during leaf development. I discovered the important roles of a novel transcriptional repression mechanism in leaf development. I demonstrated that degradation regulation finely tunes leaf size and morphology by coordinating the transcriptional repression. I also uncovered a class of transcription activators which play key roles in control of leaf development and shoot branching. These findings reveal novel conserved mechanisms in control of leaf growth and development, and provide new clues to further identify the grand conserved mechanisms in leaf development. These achievements are published in the international mainstream journals including Plant Cell, PNAS, Cell Res, New Phytol, etc. The project will further identify more components in the conserved molecular regulation networks of leaf development, and provide the gene resources and theoretical bases for molecular design breeding in crops.