Organising Tissue Cell Polarity and Growth in Plants

与我们制造的大多数东西（如汽车和电话）不同，我们周围的生物结构是通过生长产生的：一棵树是从一颗种子生长出来的，一个人类的孩子是从一个微小的受精卵生长出来的。这种增长不是由外部力量引导的，而是由内部规则自我组织和协调的。复杂的结构可以从这个过程中产生，因为组织的生长和变形以不同的速度发生，并优先在特定的方向上。一个主要的挑战是理解这种通过成长进行自我构建的过程是如何运作的。回答这个问题可能使我们能够以一种预测的方式调节生长结构，从而使我们能够更有效地利用、管理和与生命系统互动。实现这一目标的一个主要障碍是，我们目前对生长组织中定向是如何指定和协调的知之甚少。我们最好的假设是，这个过程取决于每个细胞都有一个极性，就像一个内部指南针，但这种极性是如何在组织中传播和协调的，目前还不清楚。本项目旨在通过研究植物的极性协调以及极性协调如何导致组织向特定方向生长来解决这一问题。植物细胞被壁包围，这阻碍了细胞间的直接交流。因此，极性协调被认为是间接运作的，由小分子介导，如植物激素生长素，可以通过细胞壁扩散。我们最近提出了一个关于这个过程如何导致组织间协调极性的一般假设，这个项目的一个主要目的是通过实验和计算方法的结合来测试这个假设和其他假设。为了理解极性协调的机制，我们的目标是在生长的叶组织中打开与极性控制有关的细胞斑块的基因。通过激活小块组织中的这些基因，我们希望看到周围组织的极性是如何受到影响的，以及这是如何影响细胞生长的，我们可以通过生物成像来详细跟踪。这些实验将在正常植物和某些极性成分通过突变被去除的植物中进行。我们还打算开发计算建模系统，使我们能够确定特定的假设是否可以解释观察到的极性和生长变化模式。这将涉及开发新的软件来处理组织的细胞性质以及它们生长和变形的方式。将这些实验和计算方法结合起来，我们应该能够对极性和生长是如何协调的有一个新的更深入的理解，从而提高我们管理和利用生物系统的能力。

Unlike most things that we manufacture, like cars and phones, the biological structures we see around us are generated through growth: a tree grows from a seed and a human child grows from a microscopic fertilised egg. This growth is not guided by an external hand but is self-organised, coordinated by internal rules. Complex structures can arise from this process because growth and deformation occur at varying rates over tissues and preferentially in particular directions. A major challenge is to understand how this process of self-construction through growth operates. Answering this question may allow us to modulate growing structures in a predictive way and thus enable us to exploit, manage and interact with living systems more effectively. A major block to achieving this goal is that we currently understand little about how orientations are specified and coordinated within growing tissues. Our best working hypothesis is that this process depends on each cell having a polarity, like an internal compass, but how this polarity is propagated and coordinated across a tissue remains unclear. This project aims to address this problem by studying polarity coordinated in plants and how it may lead to tissue growing out in particular orientations. Plant cells are surrounded by walls which impede direct communication from one cell to another. Polarity coordination is therefore thought to operate indirectly, mediated by small molecules, such as the plant hormone auxin, that can diffuse through the cell wall. We have recently developed a general hypothesis for how this process may lead to coordinated polarity across tissues and a major aim of this project is to test this and other hypotheses through a combination of experimental and computational methods.To understand the mechanism of polarity coordination, we aim to switch on genes that have been implicated in polarity control in patches of cells within growing leaf tissue. By activating these genes in small patches of tissue we hope to see how the polarity of the surrounding tissue is affected and how this affects the growth of the cells, which we can follow in detail with bioimaging. These experiments will be conducted in normal plants and also plants in which certain polarity components have been removed through mutation. We also intend to develop computational modelling systems that will allow us to determine whether particular hypotheses can account for the observed patterns of polarity and growth change. This will involve developing new software to deal with both the cellular nature of tissues and the way they grow and deform. Taken together these experimental and computational approaches should enable us to arrive at a new and deeper understanding of how polarity and growth are coordinated and thus advance our ability to manage and exploit biological systems.