Elucidating the mechanism of starch granule initiation in developing wheat grains

尽管淀粉对人类很重要，但我们仍然不完全了解植物是如何制造淀粉的。淀粉是一种复杂的碳水化合物，由大量葡萄糖单元结合成聚合物组成，由植物产生作为能量储存。它存在于大多数植物的叶子中，为夜间生长提供能量，但它也大量积累在我们的许多主食中，如小麦、大米和土豆。因此，淀粉是我们饮食的主要组成部分，但它也是制造各种日常用品（如纸张、纺织品和药品）所必需的。对植物如何制造淀粉的充分了解将会带来新的方法来提高主食的营养价值，增加对健康的好处，同时也会提高用于制造的淀粉的质量。淀粉中的聚合物聚集成不溶的“颗粒”。虽然我们已经很好地了解了淀粉中的聚合物是如何合成的，但我们还不知道制造淀粉颗粒的过程是如何在植物中开始的。如果不了解颗粒的形成过程，我们就无法理解是什么控制了颗粒的形成。颗粒的数量影响颗粒的大小和形状，这强烈影响淀粉在消化过程中的表现，也影响淀粉在制造过程中的表现。在过去的几十年里，研究人员一直在使用一种名为拟南芥（Arabidopsis thaliana）的模式植物来更好地了解淀粉的合成过程。最近，我在了解拟南芥叶片淀粉颗粒起始方面取得了突破，并发现了几个参与该过程的新蛋白质。有趣的是，所有这些蛋白质也存在于其他植物中，包括我们的主要作物，如小麦。因此，现在是时候超越这种模式，将这种新知识应用到我们的作物上了。这个项目的目的是了解淀粉合成是如何开始在发展小麦籽粒。利用小麦遗传学和育种的最新进展，我将发现小麦突变体没有新发现的参与颗粒起始的蛋白质的功能版本。然后，我将研究由于突变的结果，在发育中的颗粒内颗粒形成的模式是如何变化的。与此同时，我还将通过寻找与现有蛋白质结合的其他蛋白质来发现与谷物中淀粉颗粒初始化有关的新蛋白质。我还将研究小麦突变体是否改变了淀粉的特性，这对制造食品和非食品产品很重要。这将包括测试从谷物中磨出的面粉是否改变了消化率，这可能会改变食物的热值。这项研究将有助于英国创新作物的发展，因为它将导致新的小麦品种的发展，这些品种的淀粉特性改变了，吃起来更健康，或者在制造业中使用的质量更高。

Despite its importance to humankind, we still do not fully understand how starch is made in plants. Starch is a complex carbohydrate that is composed of a large number of glucose units joined together into polymers, and is produced by plants as an energy store. It is found in leaves of most plants where it provides energy for growth at night, but it also accumulates in large amounts in many of our staple foods, such as wheat, rice and potato. Starch is therefore a major component of our diets, but it is also essential in manufacturing a variety of everyday items such as paper, textiles and pharmaceuticals. A full understanding of how plants make starch will lead to new ways of improving the nutritional value of our staple foods, with added health benefits, and also improving the quality of starch used for manufacturing.The polymers in starch assemble into insoluble 'granules'. While we have a good understanding of how the polymers in starch are synthesised, we do not yet understand how the process of making the starch granule begins in the plant. Without this knowledge of the granule initiation process, we can not understand what controls the number of granules that are made. The number of granules affects the size and shape of granules, which strongly influences how starch behaves during digestion, and also during manufacturing processes. Over the last decades, researchers have been using the model plant, a small weed named Arabidopsis thaliana, to better understand the starch synthesis process. Recently, I have made a breakthrough in understanding starch granule initiation in Arabidopsis leaves, and identified several new proteins involved in the process. Interestingly, all of these proteins are also present in other plants, including our staple crops such as wheat. Therefore, it is now time to move beyond the model and apply this new knowledge to our crops. The aim of this project is understand how starch synthesis is initiated in developing wheat grains. Using the latest advances in wheat genetics and breeding, I will find wheat mutants that do not have functional versions of the newly-discovered proteins involved in granule initiation. I will then study how the pattern of granule initiation changes within the developing grain as a result of the mutation. In parallel, I will also aim to discover new proteins involved in initiating starch granules in the grain by finding other proteins that bind to the existing ones. I will also study whether the wheat mutants have altered starch properties that are important for manufacturing food and non-food products. This will include tests for whether the flour milled from the grains have altered digestibility, which may alter the calorific value of foods. This research will contribute to the development of innovative crops in the UK, as it will lead to the development of new wheat varieties with altered starch properties that are healthier to eat, or of higher quality for use in manufacturing.