Control of formative cell divisions in the stomatal lineage in Arabidopsis

植物在胚后发育过程中表现出巨大的表型可塑性，不断形成新的器官。坚硬的植物细胞壁将细胞固定在组织内，这就是为什么细胞分裂的局部组织和时空控制对于构建植物体至关重要。新的植物器官依赖于所谓的形成或不对称分裂，即产生具有不同细胞命运的子细胞。形成性分裂通常存在于干细胞小生境和源自干细胞的细胞谱系中，例如在气孔发育期间，气孔是植物叶片上对生存至关重要的气体交换孔。气孔谱系中的形成性和不对称性细胞分裂在发育水平上已经得到了很好的描述，但其潜在的分子机制仍有待探索。该项目的目的是确定植物如何执行形成和不对称分裂，并探索如何使用拟南芥气孔谱系作为一个强大的系统完成极性，细胞命运和分化。该项目的第一部分解决了核心细胞周期机制如何调节，以允许不同数量的形成分裂的问题，并将定义细胞周期调节剂CYCD 7的作用;1，这是专门在气孔谱系的最后形成分裂，其上游调控。这一部分将细胞周期的时空调控与细胞分化过程联系起来，以显示形成性分裂是如何启动的，并且非常重要的是，也限制了功能性组织图案化。形成的，不对称的细胞分裂需要细胞物质不均匀地分布到子细胞，该项目的第二部分旨在确定植物细胞产生物理不对称的机制的蛋白质。这些项目建立在初步工作的基础上，包括多种有条不紊的方法。

Plants display an enormous phenotypical plasticity and continuously form new organs during their postembryonic development. The stiff plant cell wall fixes cells within tissues, which is why the local organization and spatiotemporal control of cell division is of central importance to build the plant body. New plant organs rely on so-called formative or asymmetric divisions, i.e. the production of daughter cells with different cellular fate. Formative divisions are typically found in stem cell niches and the cell lineages originating from stem cells, e.g. during the development of stomata, the gas exchange pores on plant leaves essential for survival. Formative and asymmetric cell divisions in the stomatal lineage have been well described at a developmental level, but the underlying molecular mechanisms remain underexplored. The aim of this project is to determine how plants execute formative and asymmetric divisions and to explore how polarity, cell fate and differentiation is accomplished using the Arabidopsis stomatal lineage as a powerful system. The first part of this project addresses the question of how the core cell-cycle machinery is regulated to allow a distinct number of formative divisions and will define the role of the cell-cycle regulator CYCD7;1 that is specifically expressed during the last formative division in the stomatal lineage, and its upstream regulation. This part links the spatiotemporal regulation of the cell cycle with the process of cell differentiation to show how a formative division is initiated and, very importantly, also restricted to allow functional tissue patterning. Formative, asymmetric cell divisions require the uneven distribution of cell material to the daughter cells and the second part of the project aims at identifying proteins for the mechanisms by which plant cells generate physical asymmetries. The projects build on preliminary work and comprises multiple methodically approaches.