From stem cell activity to shoot morphology

植物的形态依赖于持续活跃的干细胞系统的活性，这种干细胞系统称为分生组织。虽然动态信号级联是建立可转化为功能形态的稳定模式的核心，但人们对基本细胞参数(如细胞大小、细胞形状或细胞力学)的贡献知之甚少。在我们第一个FOR2581资助阶段的结果的基础上，我们现在将通过利用我们分离和表征的表皮大细胞(BCE)突变体来解决这些问题。BCE表型的致病基因是核糖体RNA加工因子，因此我们将在目标1下研究核糖体发生缺陷如何导致大而形状不均匀的细胞。在目标2中，我们将使用BCE突变体作为工具来研究细胞大小、体积和力学在从分子到组织水平的形态发生过程中的作用。最后，我们将在目标3中询问分生组织定义区域中的细胞参数如何对新梢形态发生做出贡献，以及物理细胞状态如何通过自主和非自主机制影响细胞决策。我们将在图像分割、细胞机械特征记录和数学建模等领域与FOR2581的其他小组密切合作，将我们的多水平数据合成为可测试的假设和预测。综上所述，这一建议将利用第一个资助阶段中描述的BCE突变体，以促进我们对基本细胞参数(如细胞大小、形状或力学)与经过充分研究的信号系统之间的相互作用的理解，这些信号系统协同作用，产生稳定的新梢形态发生模式。

Plant form is dependent on the activity of continuously active stem cell systems, called meristems. While it is well established that dynamic signaling cascades are central for setting up stable patterns that can be translated into functional morphologies, much less is known about the contribution of basic cellular parameters, such as cell size, cell shape or cell mechanics. Building on our results from the first FOR2581 funding phase, we will now address these issues by leveraging the Big Cells in Epidermis (bce) mutant we have isolated and characterized. The causal gene for the bce phenotype is a ribosomal RNA processing factor and we will hence study how defects in ribogenesis give rise to large and unevenly shaped cells under aim 1. In aim 2, we will use the bce mutant as a tool to study the role of cell size, volume and mechanics in morphogenetic processes from the molecular to the tissue level. Finally, we will ask how cellular parameters in defined domains of the meristem contribute to shoot morphogenesis and how physical cell state impinges on cell decision making by autonomous and non-autonomous mechanisms in aim 3. We will work closely with other groups of FOR2581 in areas including image segmentation, recording of mechanical features of cells and mathematical modelling to synthesize our multilevel data into testable hypotheses and predictions. Taken together, this proposal will leverage the bce mutant characterized in the first funding phase to advance our understanding of the interplay of basic cellular parameters, such as cell size, shape or mechanics, with well-studied signaling systems that act in concert to give rise to stable morphogenetic patterns of the shoot.