Collaborative Research: Systems analysis of the interplay between oxygenic photosynthesis and nitrogen fixation in a unicellular cyanobacterium

合作研究：单细胞蓝藻含氧光合作用与固氮之间相互作用的系统分析

• 批准号: 1933660
• 负责人: Himadri Pakrasi
• 金额: $ 83.61万
• 依托单位: Washington University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-08-15 至 2024-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1933660&HistoricalAwards=false
• 关键词: Collaborative; Research; Systems; analysis; interplay

Modern agriculture is critically dependent on fertilizers as the source of biologically available nitrogen. Chemical synthesis of fertilizers is energy intensive, and the process generates greenhouse gases that are a major driver of climate change. Moreover, application of fertilizers invariably leads to run-off related issues that are detrimental to the environment. One potential solution is development of nitrogen-fixing crop plants. This is a grand challenge in biology, since oxygen is a potent inhibitor of nitrogenase, the enzyme that catalyzes nitrogen fixation. Oxygenic photosynthetic organisms are the primary producers of oxygen in the biosphere. Among them, some cyanobacterial strains can also fix nitrogen using the energy captured during photosynthesis. The central objective of this project is to develop a deep understanding of the biological system in cyanobacteria that accommodates the two antagonistic processes, photosynthesis and nitrogen fixation. Success in these efforts will unravel design principles to develop nitrogen-fixing crop plants and will have far reaching implications in basic biology as well as biotechnology. The project activities also include (i) providing training for local and international undergraduate students and (ii) outreach activities for scientifically underprivileged individuals, organized by the International Center for Energy, Environment and Sustainability at Washington University.Unicellular diazotrophic cyanobacteria are the only cellular platforms in which oxygenic photosynthesis and nitrogen fixation coexist. These microbes have developed sophisticated strategies to perform these antagonistic processes in the same cell by temporally separating them. Cyanobacteria are the only prokaryotes with a well characterized circadian clock that is thought to coordinate these two processes. However, a detailed understanding of the molecular mechanisms by which these organisms adjust their metabolism to accommodate both nitrogen fixation and photosynthesis is lacking. The plan is to use a recently developed genetic modification system for the unicellular diazotrophic strain Cyanothece sp. ATCC 51142 to strategically probe these questions. During this project, a systems biology approach is deployed to dissect the regulatory hierarchies that coordinate photosynthesis and nitrogen fixation. Overall, these studies help unlock the puzzle of the integration of photosynthesis and nitrogen fixation in a single cell. They provide a quantitative map of the highly orchestrated changes occurring during the day-night diel cycle informing how regulatory events affect metabolism as well as how the products of metabolism reset regulation.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

现代农业严重依赖肥料作为生物有效氮的来源。化肥的化学合成是能源密集型的，这一过程产生的温室气体是气候变化的主要驱动力。此外，施用化肥不可避免地会导致与径流有关的问题，对环境有害。一个潜在的解决办法是发展固氮作物。这在生物学上是一个巨大的挑战，因为氧气是固氮酶的有效抑制剂，而固氮酶是催化固氮的酶。在生物圈中，光合生物是氧气的主要生产者。其中，一些蓝藻菌株还可以利用光合作用过程中捕获的能量固定氮。该项目的中心目标是深入了解蓝细菌中的生物系统，该系统可容纳两个拮抗过程，光合作用和固氮作用。这些努力的成功将揭示开发固氮作物的设计原则，并将对基础生物学和生物技术产生深远的影响。项目活动还包括：（一）为当地和国际本科生提供培训;（二）由华盛顿大学国际能源、环境和可持续发展中心为科学上处于弱势的个人举办外联活动。这些微生物已经开发出复杂的策略，通过暂时分离它们来在同一细胞中执行这些拮抗过程。蓝细菌是唯一的原核生物与一个很好的特点生物钟，被认为是协调这两个过程。然而，缺乏对这些生物体调节其代谢以适应固氮和光合作用的分子机制的详细了解。该计划是使用最近开发的单细胞重氮营养菌株蓝杆菌ATCC 51142的遗传修饰系统，以战略性地探索这些问题。在这个项目中，系统生物学的方法被部署到解剖协调光合作用和固氮的监管层次。总的来说，这些研究有助于解开光合作用和固氮在单个细胞中整合的谜团。他们提供了一个高度协调的变化发生在昼夜周期通知如何调控事件影响新陈代谢以及如何代谢的产品重置regulation.This奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。