Rice Research Newton Fund: Exploiting a Cyanobacterial CO2 Concentrating Mechanism to Increase Photosynthesis and Yield in Rice

水稻研究牛顿基金：利用蓝藻二氧化碳浓缩机制提高水稻的光合作用和产量

基本信息

批准号：
BB/N013662/1
负责人：
Martin Parry
金额：
$ 43.48万
依托单位：
Lancaster University
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2016
资助国家：
英国
起止时间：
2016 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=BB%2FN013662%2F1
关键词：
Rice Research Newton Fund Exploiting

项目摘要

Food security is internationally recognised as one of the major global challenges of the 21st century. By 2050, it is predicted that world food production will have to increase by 50% to meet demand. This is against the pressures of global climate change and resource limitations. Meeting this challenge is going to require the development of innovative strategies to make use of our unprecedented knowledge of modern bioscience in the post genomic era. Since rice is the most important human food, consumed by more than half of the world's population, developing new highly-productive rice varieties will be fundamental to meeting the 2050 goal.Whilst substantial gains in rice yield have been obtained by traditional breeding, achievement of major increases in the future will require novel approaches. Improved photosynthesis has been identified as a major target for bioengineering for enhanced yield of C3 crop plants. Improving photosynthetic efficiency does not simply increase the amount of carbohydrate produced per hectare of land, but it also increases the amount produced per unit of water and per unit of nitrogen. This means not only environmental sustainability, but also higher income and better food security for small farmers.The properties of the carbon-fixing enzyme Rubisco (ribulose-1:5-bisphosphate carboxylase/oxygenase) are known to limit the efficiency of photosynthesis in land plants. Rubisco catalyses the combination of RuBP (ribulose-1,5-bisphophate) with CO2, but also catalyses the reaction of RuBP with oxygen, leading to photorespiration, a process in which NH3 and previously fixed CO2 are lost. Some land plants (C4 plants) and bacteria have evolved mechanisms that concentrate CO2 near Rubisco and thereby both increase photosynthetic CO2 assimilation and decrease the competing wasteful reaction with oxygen. However, rice lacks this ability. As a result, rice utilizes a Rubisco enzyme that has higher CO2 affinity but is slower than Rubisco enzymes in plants with carbon-concentrating mechanisms such as maize. Consequently, the plants must devote considerable amounts of protein, and thereby, nitrogen, to allow Rubisco to carry out adequate carbon fixation, reducing yield and biomass production. Replacing endogenous Rubisco with a faster enzyme with less CO2 specificity, along with a carbon concentrating mechanism (CCM), could significantly improve CO2 fixation, according to published models.We propose to engineer the nuclear genome of rice to express components of the cyanobacterial beta-carboxysome, including a faster Rubisco enzyme. We will identify transgenic lines of rice with the required levels of carboxysome shell proteins, internal proteins, and cyanobacterial Rubisco, which can then be crossed to express all of the novel proteins in the same line. , we will install a combination of bicarbonate transporters in order to supply CO2 to the engineered carboxysome. Finally we will also reduce the expression of the chloroplast stromal carbonic anhydrase and endogenous rice Rubisco through RNA silencing technology Based on promising results with the model plant tobacco, we believe it is time for forge ahead with a project that could bring the cyanobacterial CCM into rice for the future.

粮食安全在国际上被认为是21世纪的全球主要挑战之一。到2050年，预测世界粮食产量必须增加50％才能满足需求。这违背了全球气候变化和资源限制的压力。应对这一挑战将需要制定创新策略，以利用我们在后基因组时代对现代生物科学的前所未有的知识。由于大米是最重要的人类食品，被全世界人口的一半以上所消耗，因此开发新的高产大米品种将是实现2050年目标的基础。通过传统育种获得了大米产量的大量收益，未来的主要增长将需要新颖的方法。改进的光合作用已被确定为生物工程的主要目标，以提高C3作物植物的产量。提高光合效率不仅会增加每公顷土地生产的碳水化合物量，而且还增加了每单位水和每单位氮的产生量。这不仅意味着环境可持续性，而且对小农民的收入和更好的粮食安全性。已知碳固定酶Rubisco（Ribulose-1：5-双磷酸羧化酶/氧合酶）的特性限制了陆地工厂光合作用的效率。 Rubisco催化了Rubp（Ribulose-1,5-噬液）与CO2的组合，但也催化了Rubp与氧气的反应，导致光呼吸，这一过程丢失了NH3和以前固定的CO2。一些土地植物（C4植物）和细菌具有进化的机制，可以将二氧化碳浓缩在Rubisco附近，从而增加了光合二氧化碳的同化，并减少了与氧气相互竞争的浪费反应。但是，稻米缺乏这种能力。结果，水稻利用了具有更高二氧化碳亲和力但比含碳浓缩机制（例如玉米）的植物中的rubisco酶慢的Rubisco酶。因此，这些植物必须投入大量蛋白质，从而允许Rubisco进行足够的碳固定，减少产量和生物量的产生。根据已发表的模型，用更快的二氧化碳特异性以及碳浓缩机制（CCM）的更快酶以及碳浓缩机制（CCM）代替内源性Rubisco，可以显着改善二氧化碳的固定。我们将鉴定出具有所需水平的羧基壳蛋白，内部蛋白质和蓝细菌rubisco的转基因品系，然后可以将其交叉以表达同一条线上的所有新型蛋白质。，我们将安装碳酸氢盐转运蛋白的组合，以便向工程羧化体提供二氧化碳。最后，我们还将通过模型植物烟草的有希望的结果，通过RNA沉默技术来减少叶绿体基质碳酸酐酶和内源性米布斯科的表达，我们相信现在是时候锻造了一个可以将蓝细菌CCM带入米饭的项目。