Molecular analysis of transfer cell development in maize endosperm

几千年来，人类和动物都依赖植物种子作为生存的重要食物来源。事实上，植物种子，尤其是农作物（如水稻、大麦、小麦和玉米）的种子，在文化上具有重要意义，因为它们被认为是人类文明兴起的原因，也是农业和动物驯化的开始。今天，农作物种子以人类饲料和动物饲料的形式占世界热量摄入的三分之二，它们作为能源或生物燃料的来源也具有重要的商业价值。植物种子是有性繁殖的结果，代表着下一代的开始；因为种子发芽并长成幼苗，然后成为一株成熟的植物。种子在母体植物深埋的雌性性器官中发育。在发育的早期阶段，种子高度依赖于从母体组织获取营养，而这些营养的摄取是由专门的种子转移组织介导的。如果这种转移组织没有正确形成或功能不正确，种子发育就会受到影响，通常会导致形成较小的种子，或导致种子流产。最近对作物种子的研究表明，存在一些只在转移细胞组织中表达的基因，尽管这些基因的功能尚不清楚。我们已经确定了一小组转移细胞特异性基因，它们编码非常小的蛋白质，也位于玉米的这个组织中。我们发现，通过改变这些基因和蛋白质的功能，转移细胞组织发育异常，导致形成较小的玉米种子。这些结果表明，这些基因是玉米种子转移组织正常发育所必需的。因此，我们建议研究这些蛋白质在种子发育过程中的生物学功能，以深入了解该组织的发育是如何被调节的。因为我们还发现了与这些特定蛋白质相互作用的其他蛋白质，我们将分析它们在调节玉米种子转移组织的发育中是否同样重要。通过了解转移细胞组织是如何形成的，以及它如何能够在调节从母体组织向发育中的种子吸收营养方面发挥作用，我们可以利用这些信息来优化玉米以及其他谷物的产量和晶粒大小。

For thousands of years, humans and animals have depended on plant seeds as a food source important for their survival. In fact plant seeds, especially seeds from crop plants (such as rice, barley, wheat and maize), are of great cultural importance, as they are thought to be responsible for the rise of human civilizations and the beginning of agriculture and animal domestication. Today, crop seeds account for two-thirds of the world's caloric intake in the form of human feed and animal fodder, and they also have an important commercial value as a source of energy or biofuel. Plant seeds are formed as a result of sexual reproduction, and represent the beginning of the next generation; for seeds germinate and grow into seedlings, thereafter becoming a mature plant. Seeds develop within the deeply embedded female sexual organs of the mother plant. During early stages of development, seeds are highly dependent on obtaining their nutrients from the maternal tissues, and the uptake of such nutrients is mediated by a specialized seed transfer tissue. If this transfer tissue is not formed properly or functions incorrectly, seed development is affected, often leading to smaller seeds being formed, or seeds aborting. Recent studies of crop seeds have shown the existence of several genes that are only expressed in the transfer cell tissue, although the function of these genes remains unknown. We have identified a small group of transfer cell-specific genes that encode very small proteins also located in this tissue in maize. We have found that by altering the function of these genes and proteins, the transfer cell tissue develops abnormally, resulting in smaller maize seeds being formed. These results suggest that these genes are necessary for the correct development of the maize seed transfer tissue. We therefore propose to investigate the biological function of these proteins during seed development, with the aim of gaining insight into how development of this tissue is regulated. Because we have also identified other proteins that interact with these specific proteins, we will analyze whether they are equally important in regulating the development of the maize seed transfer tissue. By understanding both how the transfer cell tissue is formed and how it is able to fulfil its role in regulating the uptake of nutrients from the maternal tissue to the developing seed, we can use this information to optimise grain yield and grain size not just in maize, but also in other cereals.