Bilateral BBSRC-FAPESP: Cellular and regulatory basis for early plant organ growth

生物学中的一个中心问题是了解基因如何导致器官生长到特定的形状和大小。植物很容易解决这个问题，因为它们的总体生长主要是由于细胞数量的增加和单个细胞大小的增加(不需要考虑细胞移动和细胞死亡造成的“修剪”)。此外，通过对作物生长和产量的合理控制，了解植物中的器官生长为实际应用提供了一条明确的途径。然而，理解植物生长的一个主要瓶颈是，尽管我们知道几个控制器官整体大小和形状的基因，但我们不知道这些基因在细胞内控制什么过程(如细胞分裂或细胞质量增加)，从而对器官的总大小和形状产生净影响。我们的目标是通过研究模式物种拟南芥的花器官发育的早期阶段来回答这个问题。最近的两个事态发展带来了解决上述问题的前所未有的机会。一个是建立方法，允许对生长器官中的细胞几何和细胞分裂进行定量的3D分析。通过使用这些方法，该项目的英国合作伙伴最近发现，在器官发育过程中，一种名为锯齿状(JAG)的关键器官生长调节因子在协调细胞体积与细胞分裂方面具有意想不到的作用。第二个是开发技术，在器官形成的明确阶段检测由给定调控基因控制的所有基因--这可以揭示由调控基因控制的细胞功能的全套。我们的巴西/荷兰合作伙伴一直在开发这些方法，并应用它们来了解控制花器官发育的基因的作用。利用英国和巴西/荷兰合作伙伴的互补专业知识、资源和生物学兴趣，我们将把这两种方法扩展到控制植物器官生长的一组关键基因：锯齿(JAG)、AINTEGUMENTA(ANT)和CIN-TCP基因。我们将测试细胞大小和细胞分裂之间的协调是否是这些基因在器官生长的早期阶段靶向的一个关键特征。我们还将测试这些基因是否针对细胞分裂的特定步骤，并阐明这些调控基因的活动在器官生长过程中是如何结合的。最后，我们将确定在器官发育的早期阶段由JAG和CIN-TCP基因控制的基因集-这将显示这些基因的功能在多大程度上重叠，并揭示这些基因所针对的关键细胞功能，以决定器官如何生长。发展生物学目前的优先事项之一是开发能够模拟和预测器官和有机体生长方式的计算机模型。解决这项提案中的问题将是将这些模型与可以通过实验控制的分子机制联系起来的关键。最终，这些知识将允许对植物器官生长进行合理的修改，这对作物的表现有明显的影响。除了解决一个具有战略意义的基本生物学问题外，我们的工作还将在英国和巴西机构之间建立新的互惠互利的长期科学联系。

A central problem in Biology is to understand how genes cause organs to grow to a specific shape and size. Plants are convenient to address this question because their overall growth results primarily from the increase in cell numbers and increase in the size of individual cells (cell movement and "pruning" by cell death do not need to be considered). In addition, understanding organ growth in plants offers a clear path to practical use through the rational manipulation of crop growth and yield. A major bottleneck for understanding plant growth, however, is that although we know several genes that control the overall size and shape of organs, we do not understand what processes these genes control within cells (such as cell division or increase in cell mass) to result in a net effect on the total size and shape of organs. We aim to answer this question, by studying the early stages of floral organ development in the model species, Arabidopsis. Unprecedented opportunities to address the question above arise from two recent developments. One is the establishment of methods that allow quantitative, 3D analysis of cell geometry and cell division in growing organs. Using these methods, the UK partner in this project has recently found that a key regulator of organ growth, called JAGGED (JAG), has an unanticipated role in co-ordinating cell volume with cell division in developing organs. The second is the development of techniques for detection of all genes controlled by a given regulatory gene, at well-defined stages of organ formation - this can reveal the repertoire of cellular functions that are controlled by a regulatory gene. Our Brazilian/Dutch partners have been developing these methods and applying them to understand the role of genes that control floral organ development. Taking advantage of the complementary expertise, resources and biological interest of the UK and Brazilian/Dutch partners, we will extend both approaches to a key set of genes that control plant organ growth: JAGGED (JAG), AINTEGUMENTA (ANT) and CIN-TCP genes. We will test whether the co-ordination between cell size and cell division is a key feature of targeted by these genes at the early stages of organ growth. We will also test whether these genes target specific steps in cell division and clarify how the activities of these regulatory genes are combined during organ growth. Finally, we will identify the sets of genes controlled by JAG and CIN-TCP genes in the early stages of organ development - this will show to what extent the function of these genes overlap, and reveal the key cellular functions targeted by these genes to determine how the organs grow. One of the current priorities in developmental biology is to develop computer models that can simulate and predict the way organs and organisms grow. Addressing the questions in this proposal will be essential for connecting these models with molecular mechanisms that can be controlled experimentally. Ultimately, this knowledge will allow rational modification of plant organ growth, which has an obvious impact on crop performance. In addition to addressing a fundamental biological question with strategic relevance, our work will establish new and mutually beneficial long-term scientific links between UK and Brazilian institutions.