Organising Tissue Cell Polarity and Growth in Plants

与我们制造的大多数东西不同，比如汽车和手机，我们周围的生物结构是通过生长产生的：树是从种子长出来的，人类孩子是从微小的受精卵长出来的。这种增长不是由外部手引导的，而是自我组织的，由内部规则协调。这个过程中可能会出现复杂的结构，因为生长和变形在组织上以不同的速度发生，并且优先在特定的方向上发生。一个主要的挑战是理解这种通过增长进行自我建设的过程是如何运作的。回答这个问题可能会让我们以一种预测性的方式调节不断增长的结构，从而使我们能够更有效地开发、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，这一过程依赖于每个细胞都有一个极性，就像内部指南针一样，但这种极性是如何在组织中传播和协调的尚不清楚。这个项目旨在通过研究植物中协调的极性以及它如何导致组织在特定方向上生长来解决这个问题。植物细胞被墙壁包围，阻碍了一个细胞与另一个细胞的直接交流。因此，极性协调被认为是间接起作用的，由小分子介导，如植物激素生长素，可以通过细胞壁扩散。我们最近开发了一个关于这一过程如何导致组织间极性协调的一般假说，该项目的一个主要目标是通过实验和计算方法的结合来检验这一假说和其他假说。为了了解极性协调的机制，我们的目标是开启与生长中的叶组织内细胞斑块的极性控制有关的基因。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的生长的，我们可以用生物成像来详细跟踪这一点。这些实验将在正常植物中进行，也将在通过突变移除某些极性成分的植物中进行。我们还打算开发计算模型系统，使我们能够确定特定的假设是否能够解释观察到的极性和生长变化的模式。这将涉及开发新的软件，以处理组织的细胞性质以及它们生长和变形的方式。综上所述，这些实验和计算方法应该使我们能够对极性和生长是如何协调的达成新的、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.