"What makes a racehorse fast?" Exploring the role of photosynthetic and metabolic performance in growth of photosynthetic cells

“是什么让赛马跑得快？”

• 批准号: 517516852
• 负责人: Professor Dr. Zoran Nikoloski, Ph.D.
• 金额: --
• 依托单位: Arbeitsgruppe Bioinformatik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/517516852?language=en
• 关键词: What; makes; racehorse; fast; Exploring

Supplying the rapidly growing world population will require an increase in food production in the near future. Increasing the photosynthetic performance of crop plants is considered a promising approach here, as it is far from its biological limits. Particularly high photosynthetic outputs often occur in organisms that have to cope with special stress conditions. For example, Chlorella ohadii, a green microalga recently isolated from a desert biological soil crust, exhibits the fastest growth rate and highest photosynthetic rate per chlorophyll ever reported for a photosynthetic organism. The question arises, what defines the upper limit for the growth of a photosynthetic cell? We have already shown that the high growth rates of C. ohadii result from its high metabolic flexibility. Accordingly, the main goal of this project is to decipher bottlenecks in the metabolic pathways of photosynthetic cells that limit the growth of algae and plants. This goal will be achieved by the following approaches: first, we want to comparatively investigate the metabolic rates (fluxes) in the central and photosynthetic metabolism of very fast (C. ohadii) and slower (C. reinhardtii) growing microalgae under different conditions to identify reactions or combinations of reactions that could be causative for the different growth rate ("potential bottlenecks"). Second, we aim to determine the absolute concentrations of key enzymes that catalyze the most important reactions in the central and photosynthetic metabolic pathways. This will allow us to determine their in vivo kcat levels to better assess metabolite fluxes based on metabolic models. Third, we will use transgenic approaches to test whether and which of the identified reactions limit the growth of the slower-growing, genetically accessible alga C. reinhardtii. For this, we want to replace C. reinhardtii genes with orthologs from the fast-growing alga C. ohadii or alter the expression of native C. reinhardtii genes. Finally, we aim to investigate the effects of these metabolic interventions on growth and photosynthetic rates, as well as metabolite fluxes and carbon allocation patterns in the metabolic network of the engineered strains. In the long term, the knowledge gained from the microalgal systems will be used to modify crops to produce higher yields.

为了满足迅速增长的世界人口的需求，在不久的将来需要增加粮食产量。提高作物的光合性能被认为是一种很有前途的方法，因为它远远超出了其生物学极限。特别高的光合作用输出常常发生在必须科普特殊压力条件的生物体中。例如，Chlorella ohadii，一种最近从沙漠生物土壤结皮中分离的绿色微生物，表现出最快的生长速率和最高的光合作用生物体的每叶绿素光合速率。问题来了，什么定义了光合作用细胞生长的上限？我们已经证明，C。Ohadii由其高代谢灵活性产生。因此，该项目的主要目标是破译限制藻类和植物生长的光合细胞代谢途径中的瓶颈。这一目标将通过以下方法实现：首先，我们想比较研究的代谢率（通量）在中心和光合代谢的非常快（C。ohadii）和较慢（C. reinhardtii）在不同条件下生长微藻，以鉴定可能导致不同生长速率的反应或反应组合（“潜在瓶颈”）。第二，我们的目标是确定催化中心和光合代谢途径中最重要反应的关键酶的绝对浓度。这将使我们能够确定它们的体内kcat水平，以更好地评估基于代谢模型的代谢物通量。第三，我们将使用转基因方法来测试是否以及哪些已确定的反应限制了生长较慢的、遗传上可接近的BKC的生长。莱因哈德氏菌为此，我们要替换C。reinhardtii基因与来自快速生长的C.reinhardtii的直系同源物。ohadii或改变天然C. reinhardtii基因最后，我们的目标是研究这些代谢干预对生长和光合速率的影响，以及代谢产物通量和碳分配模式的代谢网络的工程菌株。从长远来看，从微藻系统中获得的知识将用于改造作物，以提高产量。