CAREER: Glycogen metabolism kick-starts photosynthesis in cyanobacteria

事业：糖原代谢启动蓝细菌的光合作用

• 批准号: 2414925
• 负责人: Xin Wang
• 金额: $ 89.76万
• 依托单位: University of Florida
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-11-01 至 2026-05-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2414925&HistoricalAwards=false
• 关键词: CAREER; Glycogen; metabolism; kick; starts

Life on Earth depends on photosynthesis to harvest solar energy. During the day, plants and other photosynthetic organisms use solar energy to fix carbon dioxide and store excess carbon as carbon polymers such as starch or glycogen. At night, these storage carbons are broken down as the energy source for dark survival. The dark-to-light transition represents a universal environmental stress for photosynthetic lifeforms. For example, many metabolites necessary for photosynthetic reactions upon light exposure are limited or depleted due to metabolic reactions conducted in dark. It is important for photosynthetic organisms to have a mechanism in place to cope with this stress and ensure healthy photosynthetic performance upon exposure to light. How photosynthetic organisms achieve this dark-to-light transitions remains unclear. This research project applies cutting-edge biochemical and systems biology approaches to dissect the molecular mechanisms that allow this dark to light transition to occur in a model photosynthetic blue green alga. Knowledge gained from this research will how storage polymers like glycogen pave the way for carbon dioxide fixation to occur during the dark to light transition and eventually lead to ways to improve photosynthetic efficiency for crop productions. The research project also provides training opportunities for one postdoctoral researcher, one graduate student, and several undergraduate students. Components of this research are also integrated in a cluster education program as well as in the form of a special topics course on Synthetic Biology to broaden the training opportunity and strengthen scientific literacy for both undergraduate and graduate students. Cyanobacteria experience drastic metabolic changes under daily light/dark cycles. The smooth metabolic transition from dark to light is crucial for healthy photosynthetic performance and the overall fitness of phototrophs. It is known that glycogen metabolism is involved in supporting the initiation of the Calvin-Benson-Bassham (CBB) cycle reactions during dark-to-light transitions in the cyanobacterium Synechococcus elongatus PCC 7942. However, the molecular mechanisms of how glycogen metabolism supports photosynthesis are not clear. This project applies proteomics, metabolomics, metabolic flux analysis, and photochemical analyses to characterize the coping mechanism of cyanobacteria for the dark-to-light transition stress. The research activities will illustrate the status of a stalled CBB cycle, and understand how glycogen metabolism helps replenish and restart carbon fixation reactions, as well as protecting Photosystem I from photoinhibition during dark-to-light transitions. Discoveries from the research will significantly advance the understanding on a fundamental mechanism employed by photosynthetic lifeforms to cope with the dark-to-light transition stress and further our knowledge on energy balance between photosynthetic light reactions and carbon fixation. Results from the study also benefit photosynthesis redesign research in the field of synthetic biology for sustainable food supply.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.

地球上的生命取决于光合作用来收获太阳能。白天，植物和其他光合生物使用太阳能固定二氧化碳并将多余的碳作为碳聚合物（例如淀粉或糖原）储存。到了晚上，这些储物碳被分解为黑暗生存的能源。黑暗到光的过渡代表了光合生命形式的普遍环境压力。例如，由于在黑暗中进行的代谢反应，光合作用反应所需的许多代谢产物受到限制或耗尽。对于光合生物来说，具有应对这种压力的机制并确保在暴露于光线后确保健康的光合作用的机制很重要。光合生物如何实现这种黑暗到光线的过渡尚不清楚。该研究项目采用了尖端的生化和系统生物学方法来剖析分子机制，使这种黑暗到光转换发生在模型的光合蓝绿色藻类中。从这项研究中获得的知识将如何在黑暗到光过渡期间发生二氧化碳固定量之类的储存聚合物铺平道路，并最终导致提高作物生产的光合作用效率的方法。该研究项目还为一位博士后研究员，一名研究生和几位本科生提供培训机会。这项研究的组成部分还纳入了集群教育计划，以及有关合成生物学的特殊主题课程的形式，以扩大培训机会并增强本科生和研究生的科学素养。蓝细菌在每天的光/黑暗周期下经历了急剧的代谢变化。从黑暗到光的平滑代谢过渡对于健康的光合作用和光养的整体适应性至关重要。众所周知，糖原代谢参与了支持在蓝细菌cyanobacterium synechocococcus elongatus pcc 7942中加尔文·本森·巴萨姆（CBB）周期反应的开始。该项目采用蛋白质组学，代谢组学，代谢通量分析和光化学分析来表征蓝细菌的应对机理，以呈黑暗到光线过渡应力。研究活动将说明停滞的CBB周期的状态，并了解糖原代谢如何有助于补充和重新启动碳固定反应，并保护光系统I在黑暗到光线过渡过程中免受光抑制。研究的发现将大大提高对光合生命形式采用的基本机制的理解，以应对黑暗到光线的过渡压力，并进一步我们对光合光反应和碳固定之间的能量平衡的了解。该研究的结果还受益于可持续食品供应的合成生物学领域的光合作用重新设计研究。该奖项反映了NSF的法定任务，并且使用基金会的知识分子优点和更广泛的影响评估标准，被认为值得通过评估来获得支持。