The role of cell geometry, growth and mechanics in plant cell division.

细胞几何形状、生长和力学在植物细胞分裂中的作用。

• 批准号: 357135584
• 负责人: Dr. Richard S Smith
• 金额: --
• 依托单位: John Innes Centre
• 依托单位国家: 德国
• 项目类别: Research Units
• 财政年份: 2017
• 资助国家: 德国
• 起止时间: 2016-12-31 至 2018-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/357135584?language=en
• 关键词: role; cell; geometry; growth; mechanics

Since plant growth is symplastic, plants must create their form by precisely regulating cell growth and division. It has been proposed that plants have default rules for symmetric cell division, defined as divisions where the daughter cells have the same fate. Proposed rules have been based on the geometry of the cell, growth directions, or mechanical stresses, although none of these seems able to capture plant-wide cell behaviour. Since these factors are interrelated, it seems likely that there is an underlying default rule for all cells, and the differences observed are due to different growth rates, the mechanical environment perceived by the cell or other parameters. It has also been reported that non-symmetric or formative divisions often do not follow the default rule, and that there is an association between geometric asymmetry and daughter cell fate asymmetry.  In this project we will use a computational morphodynamics approach to quantify growth and cell division in 3D, to determine which parameters the cell is using to orient division. We will build a 3D mechanical model of the tissue under study, in order to determine the stresses that cell perceives, and how these may be integrated into the determination of division plane orientation. We will then extend the model to understand how rules might be modified for formative divisions.We will primarily use two biological systems developed by other partners in the RU. The emergence of Arabidopsis lateral root is the focus of the Maizel lab, and the development of the Arabidopsis ovule and integuments is the focus of the Schneitz lab. Both are good systems to study primary morphogenesis, as they begin with relatively few cells, have variable and often highly anisotropic growth, and result in the specification of non-trivial shapes with several different cell types. The systems show promise for full 3D imaging, and in the case of lateral root emergence, full 3D time-lapse. We will use these systems to determine the default rules for cell division in the Arabidopsis lateral root and the ovule, with the goal to unify the many different but seemingly related division rules proposed previously. We will investigate how formative divisions can be integrated into the model, and whether they are just a straightforward variation of the underlying mechanism. We will also investigate the relationship between geometry asymmetry and fate asymmetry in these systems.

由于植物生长是共生的，因此植物必须通过精确调节细胞生长和分裂来创造其形态。有人提出，植物具有对称细胞分裂的默认规则，即子细胞具有相同命运的分裂。提议的规则是基于细胞的几何形状、生长方向或机械应力，尽管这些似乎都无法捕获全植物的细胞行为。由于这些因素是相互关联的，所有细胞似乎都存在潜在的默认规则，并且观察到的差异是由于不同的生长速率、细胞感知的机械环境或其他参数造成的。据报道，非对称或形成性分裂通常不遵循默认规则，并且几何不对称与子细胞命运不对称之间存在关联。  在这个项目中，我们将使用计算形态动力学方法来量化 3D 生长和细胞分裂，以确定细胞使用哪些参数来定向分裂。我们将为所研究的组织建立 3D 力学模型，以确定细胞感知的应力，以及如何将这些应力整合到划分平面方向的确定中。然后，我们将扩展该模型，以了解如何针对形成性分裂修改规则。我们将主要使用 RU 中其他合作伙伴开发的两个生物系统。拟南芥侧根的出现是 Maizel 实验室的重点，拟南芥胚珠和珠被的发育是 Schneitz 实验室的重点。两者都是研究初级形态发生的良好系统，因为它们从相对较少的细胞开始，具有可变且通常高度各向异性的生长，并导致几种不同细胞类型的非平凡形状的规范。该系统有望实现全 3D 成像，并且在侧根出现的情况下，实现全 3D 延时拍摄。我们将使用这些系统来确定拟南芥侧根和胚珠细胞分裂的默认规则，目标是统一之前提出的许多不同但看似相关的分裂规则。我们将研究如何将形成性划分整合到模型中，以及它们是否只是底层机制的简单变体。我们还将研究这些系统中几何不对称性和命运不对称性之间的关系。