Increasing seed yields by the targeted modulation of brassinosteroids (based at Rothamsted Research)

种子是植物生长的主要繁殖物，同时也是最重要的农产品，至少占世界粮食供应的70%。随着人口的增加和农业用地的减少，提高作物产量变得越来越迫切。增加种子作物品种的种子规模和数量是实现这一目标和改善粮食安全的重要途径。在种子是作物最重要的部分的情况下，例如油菜、小麦、玉米和水稻，提高产量的最好方法是种植种子数量更多的植物，而不会伴随着种子大小或质量的下降。在植物中，如油籽，种子是在豆荚中产生的，每荚种子数量通常与种子产量呈正相关。油菜素类化合物控制着种子产量、开花时间和抗逆性等一系列重要的农艺性状。油菜素内酯生物合成或信号基因在拟南芥和水稻中的过度表达导致了种子产量的增加。然而，在许多情况下，这些基因的结构性过度表达导致了对植物生长和产量的不良负面影响。这意味着油菜素类固醇合成或信号传递的变化可能会对感兴趣的性状造成积极和消极影响的结合。因此，组织特异性启动子的使用代表了一种通过调节油菜素类固醇水平和利用它们在植物发育中的作用来提高作物产量的策略。该项目将专注于在不同的组织特异性启动子的控制下将选定的油菜素类固醇相关基因导入拟南芥，并研究其对种子产量性状的后续影响。具体地说，我们将识别增加植物胚珠数量的基因，从而导致每荚种子数量的增加。然后，我们将测试这些引入的基因提高种子产量的能力。该项目将结合分子、发育和细胞生物学技术，提供植物遗传学、基因组学以及生物信息学、统计学和显微技术方面的培训。

Seeds constitute the main propagule for plant growth and at the same time are the most importantagricultural product, accounting for at least 70% of the world's food supply. With rising populationand diminishing agricultural land, it is increasingly urgent to improve crop yields. Increasing seed sizeand number in seed crop species are important routes to achieving this goal, and improving foodsecurity. In situations where seeds are the most important part of the crop, e.g. oil-seed rape, wheat,maize, and rice, the best way to increase yield is to produce plants that have a higher number of seedswith no concomitant decrease in seed size or quality. In plants, such as oilseeds, where seeds areproduced in pods, seed number per pod is often positively correlated with seed yield. In addition,there is also a positive correlation between oil content in seeds and seed number per pod.Brassinosteroids control a large number of agronomically important traits including seed yield,flowering time, and stress tolerance. Over-expression of brassinosteriod biosynthetic or signallinggenes in Arabidopsis and rice have resulted in concomitant increases in seed yield. However, in manycases constitutive over-expression of these genes led to undesirable negative effects on plant growthand yield. This implies that changes in brassinosteroid synthesis or signalling can cause a combinationof positive and negative effects on traits that are of interest. Therefore, the use of tissue specificpromoters represents a strategy for increasing crop yield by modulating the level of brassinosteroidsand harnessing their role in plant development.The project will focus on introducing selected brassinosteroid-related genes into Arabidopsis underthe control of distinct tissue-specific promoters and investigating the subsequent effects on seed yieldtraits. Specifically, we will identify genes that increase the number of ovules in a plant leading to anincreased number of seed per pod. We will then test the ability of these introduced genes to increaseseed yield overall.The project will use a combination of molecular, developmental, and cell biological techniques andprovide training in the disciplines of plant genetics, genomics as well as bioinformatic, statistical, andmicroscopy techniques.