Anoxygenic Photosynthesis in Cyanobacteria

蓝藻的缺氧光合作用

• 批准号: 1939303
• 负责人: Trinity Hamilton
• 金额: $ 38.49万
• 依托单位: University of Minnesota-Twin Cities
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-06-01 至 2024-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1939303&HistoricalAwards=false
• 关键词: Anoxygenic; Photosynthesis; Cyanobacteria

Understanding the evolution of photosynthesis, the process of using light energy to convert carbon dioxide (CO2) into biomass, remains an outstanding question. A number of factors confound our ability to trace the evolution of photosynthesis: associated observed chemical limitations are not clearly defined in genetic information and horizontal gene transfer (the transfer of genetic information between microorganisms) hinders phylogenetic approaches. In the absence of characterized deeply-branching microorganisms, a robust phylogenomic framework, and undisputed biosignatures in the rock record, facultative anoxygenic photosynthesis in extant cyanobacteria represents an opportunity to better understand and constrain the evolution of photosynthesis. In this project, the investigator will characterize photosynthesis in an emerging model cyanobacterium, Leptolyngbya sp. strain hensonii, isolated from an anoxic, sulfide-rich sinkhole. This research will evaluate the genetic response of Leptolyngbya sp. strain hensonii to the presence of sulfide (which has been linked to inhibition of oxygenic photosynthesis) and the potential for a cyanobacterium to express a single photosystem based on environmental conditions. Collectively, the data will provide insight into the physiology and potential success of cyanobacteria prior to the evolution of oxygenic photosynthesis. The study will examine the role of life in the transformation and evolution of Earth's geochemical cycles and the evolution of photosynthesis, which is an outstanding question in geobiology. The project will train a graduate student and an undergraduate student. In addition, the research team will develop a demonstration for Market Science to broadly disseminate findings at Farmers' Markets in and around the Twin Cities area of Minnesota.The ability to harvest light and fuel cellular processes through phototrophy is arguably one the most important biological innovations in Earth history. Yet, understanding the evolution of photosynthesis remains an outstanding question in geobiology. Oxygenic photosynthesis is often cited as the most important microbial innovation having tipped the scale from a reducing early Earth to an oxygenated world that eventually lead to complex life. However, oxygenic phototrophs use two reaction centers: Photosystem II and Photosystem I for light-driven oxidation of water to fuel primary productivity. In extant sunlit environments where low oxygen concentrations and sulfide persist, some cyanobacteria can use sulfide as the electron donor to photosystem I, performing anoxygenic photosynthesis. In the absence of characterized deeply-branching isolates, a robust phylogenomic framework, and irrefutable biosignatures in the rock record, facultative anoxygenic photosynthesis in extant cyanobacteria represents a tractable system for examining the evolution of photosynthesis including the potential for an early evolving one-photosystem cyanobacterium. The proposed research plan will integrate a set of physiological studies coupled with systems biology approaches—transcriptomics and proteomics—to characterize an emerging model cyanobacterium isolated from a sulfidic, anoxic environment. The following objectives will guide this work: 1) define the molecular machinery necessary for anoxygenic photosynthesis; 2) characterize the effects of sulfide on photosystem II during anoxygenic photosynthesis; 3) determine oxidation kinetics of sulfide during anoxygenic photosynthesis; 4) examine the enhancement of carbon fixation in the presence of sulfide. The proposed research will examine the role of life in the transformation and evolution of Earth's geochemical cycles and the evolution of photosynthesis.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.

了解光合作用的演变，使用光能将二氧化碳（CO2）转化为生物质的过程仍然是一个杰出的问题。许多因素混淆了我们追踪光合作用演变的能力：相关的观察到的化学限制并未在遗传信息和水平基因转移（微生物之间的遗传信息转移）中明确定义，这阻碍了系统发育方法。在没有特征性的深度微生物，稳健的系统切开框架和无可争议的生物签名中，在岩石记录中，兼性的蓝细菌中的兼性无氧光合作用代表了更好地理解和约束光合作用的演变的机会。在该项目中，研究人员将在新兴模型蓝细菌（Leptolyngbya sp。）中表征光合作用。菌株Hensonii，从缺氧，富含硫化物的污水孔中分离出来。这项研究将评估Leptolyngbya sp。的遗传反应。将hensonii菌株与硫化物的存在（与抑制氧光合作用有关），并有可能根据环境条件表达基于环境条件的单一光系统。总体而言，数据将洞悉氰基光合作用之前的蓝细菌的生理和潜在成功。该研究将研究生命在地球地球化学周期的转化和演变中的作用以及光合作用的演变，这在地球学中是一个杰出的问题。该项目将培训研究生和一名本科生。此外，研究团队将为市场科学开发一个演示，以广泛传播明尼苏达州双城地区及其周围农贸市场的发现。通过光萎缩，通过光萎缩收获光线和燃料蜂窝过程的能力可以说是地球历史上最重要的生物创新之一。然而，了解光合作用的演变仍然是地球生物学中的一个杰出问题。氧光合物通常被认为是最重要的微生物创新，从而使量表从还原早期的地球变成了有时会导致复杂生活的氧化世界。但是，氧合照片使用两个反应中心：光系统II和光系统I用于水的氧化氧化，以促进主要生产力。在氧气浓度低和硫化物持续存在的过度阳光环境中，某些蓝细菌可以使用硫化物作为光系统I的电子供体，进行无氧光合作用。在没有特征性的深部分离株，稳健的系统生成框架和摇滚记录中无可辩驳的生物签名之中，额外的氰基杆菌中的兼性无氧光合作用代表了一种可拖延系统，可用于检查光合作用的演变，包括早期发展的单位cyabocys cyanob，包括早期的cyabocys cyanob。拟议的研究计划将整合一组生理研究，再加上系统生物学方法（转录组学和蛋白质组学），以表征从硫化，缺氧环境中分离出的新兴模型蓝细菌。以下对象将指导这项工作：1）定义无氧光合作用所需的分子机械； 2）表征硫化物对光合体光合作用过程中光系统II的影响； 3）确定硫化物的氧化动力学在无氧光合作用过程中； 4）检查在存在硫化物的情况下碳固定的增强。拟议的研究将研究生命在地球地球化学周期的转型和演变中的作用以及光合作用的演变。该奖项反映了NSF的法定任务，并通过评估基金会的智力优点和更广泛的影响来审查标准。