Bilateral NSF/BIO-BBSRC Synthesis of Microcompartments in Plants for Enhanced Carbon Fixation

NSF/BIO-BBSRC 双边合成植物微室以增强碳固定

• 批准号: BB/N016009/1
• 负责人: Martin Parry
• 金额: $ 61.58万
• 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%2FN016009%2F1
• 关键词: Bilateral; NSF; BIO; BBSRC; Synthesis

Global demand for food and fuel is steadily increasing, while gains in yield of many major food crops through traditional breeding have leveled off in recent years. The natural variation that has been the source of substantial crop improvement is becoming exhausted, so that new efforts, including input from synthetic biology will be needed to improve photosynthetic efficiency. More than 90% of biomass is derived directly from photosynthetic products. The properties of the carbon-fixing enzyme Rubisco (ribulose-1:5-bisphosphate carboxylase/oxygenase) limit the efficiency of photosynthesis in land plants. Rubisco can catalyze the combination of RuBP (ribulose-1,5-bisphophate) with CO2, but also can catalyze the reaction of RuBP with oxygen, leading to photorespiration, a process in which previously fixed CO2 is lost. Cyanobacteria and some land plants have evolved to deal with an increase of oxygen in the atmosphere by developing mechanisms that concentrate CO2 near Rubisco. However, many of the globally important crop plants lack this ability; instead, they utilise Rubisco enzymes that have higher CO2 affinity but are slower than Rubisco enzymes in plants with carbon-concentrating mechanisms such as maize. Consequently, these plants must devote considerable amounts of protein, and thereby, nitrogen, to allow Rubisco to carry out adequate amounts of carbon fixation, reducing yield and biomass production.One of the outstanding millenial goals is to find ways to improve photosynthetic yields for enhanced biomass production. Replacing endogenous Rubisco with a faster enzyme with less CO2 specificity, along with a carbon concentrating mechanism, is one way to significantly improve CO2 fixation, according to published computational models. We propose to undertake work to this end. We will install a novel cyanobacterial-based carbon-concentrating mechanism in a land plant chloroplast and provide the necessary molecular machinery to facilitate its operation. Regulatory modules will be produced to express components of the cyanobacterial carboxysome from the chloroplast genome and chloroplast membrane-targeted bicarbonate pumps from the nuclear genome. As a proof of principle, this work will be carried out in tobacco, a species in which chloroplast transformants can be most rapidly obtained. We have already established the ground work for this engineering feat, demonstrating that several of the components can be introduced; for example, to generate novel microcompartments within the tobacco chloroplast. We expect the knowledge gained from the project will inform subsequent efforts to enhance photosynthesis in other species, for example by introducing synthetic microcompartments into species such as soybean, in which technology is already available for chloroplast and nuclear transformation. Knowledge will be gained through biochemical and microscopic studies, for example about the effect of stoichiometry of cyanobacterial proteins on microcompartment size, morphology, and function in carbon concentration and photosynthesis. We will examine features of the gene regulatory sequences on the synthetic chloroplast operons needed to express proteins in the amounts and ratios needed for assembly of microcompartments. We expect the findings to be valuable also for future projects and additions of other capabilities to plants by synthesis of artificial microcompartments.

全球对粮食和燃料的需求正在稳步增长，而近年来通过传统育种获得的许多主要粮食作物的产量增长已经趋于平稳。自然变异一直是大幅改善作物的源泉，但它正在枯竭，因此需要新的努力，包括合成生物学的投入，以提高光合效率。超过90%的生物质直接来自光合产物。固碳酶Rubisco（核酮糖-1：5-二磷酸羧化酶/加氧酶）的性质限制了陆地植物光合作用的效率。Rubisco可以催化RuBP（核酮糖-1，5-二磷酸盐）与CO2的结合，但也可以催化RuBP与氧气的反应，导致光呼吸，这是一个失去先前固定的CO2的过程。蓝细菌和一些陆地植物已经进化到通过发展将CO2聚集在Rubisco附近的机制来处理大气中氧气的增加。然而，许多全球重要的作物植物缺乏这种能力;相反，它们利用具有更高CO2亲和力但比具有碳浓缩机制的植物（如玉米）中的Rubisco酶慢的Rubisco酶。因此，这些植物必须投入大量的蛋白质，从而氮，使Rubisco进行足够量的碳固定，减少产量和生物质生产。根据已发表的计算模型，用具有较低CO2特异性的更快的酶代替内源性Rubisco，沿着碳浓缩机制，是显著改善CO2固定的一种方法。我们建议为此开展工作。我们将在陆地植物叶绿体中安装一种新的基于蓝藻的碳浓缩机制，并提供必要的分子机制以促进其运作。将产生调控模块以表达来自叶绿体基因组的蓝藻羧基体的组分和来自核基因组的叶绿体膜靶向碳酸氢盐泵。作为原理的证明，这项工作将在烟草中进行，烟草是一种可以最快获得叶绿体转化体的物种。我们已经为这项工程壮举建立了基础工作，证明可以引入几种成分;例如，在烟草叶绿体内产生新的微区室。我们希望从该项目中获得的知识将为随后在其他物种中增强光合作用的努力提供信息，例如通过将合成微区室引入大豆等物种，其中技术已经可用于叶绿体和核转化。知识将通过生物化学和微观研究获得，例如关于蓝藻蛋白质的化学计量对微区室大小，形态和碳浓度和光合作用功能的影响。我们将研究合成叶绿体操纵子上的基因调控序列的特征，这些操纵子需要以组装微区室所需的量和比例表达蛋白质。我们希望这些发现对未来的项目和通过合成人工微区室来增加植物的其他能力也有价值。

项目成果

Towards engineering carboxysomes into C3 plants.

• DOI: 10.1111/tpj.13139
• 发表时间: 2016-07
• 期刊: The Plant journal : for cell and molecular biology
• 作者: Hanson MR;Lin MT;Carmo-Silva AE;Parry MA
• 通讯作者: Parry MA

Hybrid Cyanobacterial-Tobacco Rubisco Supports Autotrophic Growth and Procarboxysomal Aggregation

杂交蓝藻-烟草 Rubisco 支持自养生长和原羧基体聚集

• DOI: 10.1104/pp.19.01193
• 发表时间: 2019
• 期刊: Plant Physiology
• 影响因子: 7.4
• 作者: Orr, Douglas J.;Worrall, Dawn;Lin, Myat T.;Carmo-Silva, Elizabete;Hanson, Maureen R.;Parry, Martin A. J.
• 通讯作者: Parry, Martin A. J.