Decoding how signalling from the plant cell wall controls cell fate decisions in the shoot apical meristem

固执的生活方式强加给植物的一个决定性特征是它们对环境的显著发育可塑性。在这种可塑性的基础上，不断活跃的多能干细胞为新器官的终身胚胎后形成提供燃料。由于植物细胞被包裹在细胞壁中，因此不能移动，它们各自的命运决定程序强烈地依赖于生物体内的相对位置。此外，植物的生长在很大程度上依赖于由细胞壁重塑介导的细胞扩张，突出了细胞壁是植物形态发生的主要决定因素。假设细胞壁的状态受到细胞表面受体的持续监测，直接将细胞壁状态连接到细胞内的基因调控网络。然而，这些细胞壁信号通路在植物发育中的作用，以及细胞壁特性和力学对细胞行为和细胞特性的贡献还不是很清楚。我们以前的结果表明，细胞壁信号成分参与了细胞特性的维持，细胞壁属性的控制对于干细胞种群的永久存在和器官发生是必不可少的。这些结果表明，植物细胞壁不仅参与细胞分化，而且反馈发育转变，为研究直接的物理环境如何能够指导植物细胞命运的决定铺平了道路。因此，在拟议的研究框架内，我们的目标是破译细胞壁信号如何控制模式植物拟南芥的细胞身份。为此，我们将研究干细胞中细胞壁属性是如何控制的，并揭示来自细胞壁的信号如何影响特定细胞类型的转录特征。此外，我们将评估细胞壁信号如何与茎顶端分生组织模式的已知调节因子相交，并确定细胞壁触发的信号转导的分子成分。

A defining feature of plants, imposed by a sessile lifestyle, is their remarkable developmental plasticity in response to the environment. At the basis of this plasticity are continuously active pluripotent stem cells, which fuel the life-long post-embryonic formation of new organs. Since plant cells are encased in cell walls and thus immotile, their individual fate-specification program is strongly dependent on the relative position within the organism. In addition, plant growth to a large extent relies on cell expansion mediated by cell wall remodelling, highlighting the cell wall as a major determinant of plant morphogenesis. It is assumed that the state of the cell wall is under constant surveillance by cell surface receptors directly linking cell wall state to intracellular gene-regulatory networks. However, the role of these cell wall signalling pathways in plant development and the contribution of cell wall properties and mechanics to cell behaviour and cell identity are not well understood. Our previous results demonstrate that cell wall signalling components are involved in maintenance of cell identity and that control of cell wall properties is essential for the perpetuation of stem cell populations and organogenesis. These results point to a scenario in which the plant cell wall is not only involved in cell differentiation, but also feeds back on developmental transitions, paving the way to study how the immediate physical environment is able to guide cell fate decisions in plants. In the framework of the proposed research, we therefore aim to decipher how cell wall signalling controls cell identity in the model plant Arabidopsis thaliana. To this end, we will study how cell wall properties are controlled in stem cells and unravel how signals from the cell wall affect the transcriptional signatures of specific cell types. Moreover, we will assess how cell wall signalling intersects with known regulators of shoot apical meristem patterning and identify molecular components of cell wall-triggered signal transduction.