Collaborative Research: Improving plant productivity and models of carbon exchange by resolving mechanisms of excess carbon release in photorespiration

合作研究：通过解决光呼吸中过量碳释放的机制来提高植物生产力和碳交换模型

• 批准号: 2030295
• 负责人: Aaron Liepman
• 金额: $ 13.5万
• 依托单位: Eastern Michigan University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-03-01 至 2025-02-28
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2030295&HistoricalAwards=false
• 关键词: Collaborative; Research; Improving; plant; productivity

During photosynthesis, plants use energy from sunlight to convert carbon dioxide from the atmosphere into biomass. This biomass includes the food, fiber and fuel required by humans and other life on this planet. During this conversion, the initial step of photosynthesis can react with atmospheric oxygen instead of carbon dioxide, which produces compounds that must be recycled. This recycling process, called photorespiration, requires large percentages of the plant’s energy reserves and releases carbon dioxide, thereby reducing plant growth and productivity. Photorespiration is affected by environmental conditions, increasing relative to photosynthesis as temperature rises. This research project explores the temperature response of photorespiration to determine how it will respond under future climates and seeking strategies to improve its efficiency. Findings from this proposal will be integrated into education activities and disseminated widely. Diverse students will be engaged via a research collaboration with a primary undergraduate institution serving under-represented students. Additionally, the potential for this work to improve crop productivity and the importance of models in plant biology will be disseminated by continuing Sounds of Science performances. The Sounds of Science is a unique collaboration where composers create music from research data provided by a plant scientist. Presentations where the investigators present an overview of the research and the compositions are performed will be recorded in partnership with local public media and have the potential to reach a public audience of ~500,000 Michigan residents.Photorespiration is the second largest metabolic flux of carbon in an illuminated leaf and occurs when rubisco, the initial enzyme of carbon fixation, binds with oxygen instead of carbon dioxide and produces a molecule that must be recycled. Photorespiration recycles this molecule into Calvin-Benson cycle intermediates at the great cost of carbon. Understanding the mechanisms of carbon dioxide release during photorespiration is critical for predicting plant responses to climate change and potentially engineering plants with improved carbon assimilation and productivity. When temperature increases, photorespiration releases even more carbon dioxide per rubisco oxygenation, but the mechanism of this increase is unknown. The objective of this proposal is to resolve the mechanisms of this excess carbon dioxide release at high temperatures using an innovative combination of metabolic modeling, in vivo gas exchange, and isotopic labeling approaches. The central hypothesis of this proposal is that excess carbon dioxide release occurs from photorespiration at elevated temperatures when intermediates react non-enzymatically in the peroxisome with hydrogen peroxide produced from photorespiration. This hypothesis assumes that under ambient temperatures hydrogen peroxide is efficiently detoxified by the enzyme catalase, but under elevated temperatures catalase is unable to remove hydrogen peroxide quickly enough to minimize non-enzymatic decarboxylation reactions. The results of this project will reach across disciplinary boundaries with the strong potential to improve earth-system models of carbon cycling and to identify key traits for adapting photosynthesis to real-world growing conditions.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.

在光合作用期间，植物利用阳光的能量将大气中的二氧化碳转化为生物量。这种生物质包括人类和该星球上其他生命所需的食物，纤维和燃料。在此转换过程中，光合作用的初始步骤可以与大气中的氧气反应，而不是二氧化碳，该氧化物产生必须回收的化合物。这种回收过程称为光呼吸，需要大部分植物的能源储量并释放二氧化碳，从而降低植物的生长和生产率。光呼吸受环境条件的影响，随着温度的升高，相对于光合作用而增加。该研究项目探讨了光呼吸的温度响应，以确定其在未来的气候下如何响应并寻求提高其效率的策略。该提案的发现将纳入教育活动并广泛传播。多样化的学生将通过与一家为代表性不足的学生提供的小学本科机构进行研究合作。此外，这项工作的潜力提高了作物生产率，模型在植物生物学中的重要性将通过持续的科学表演来传播。科学的声音是独特的合作，作曲家从植物科学家提供的研究数据中创建音乐。调查人员提出研究概述和作品的演讲将与当地公共媒体合作记录，并有可能吸引约500,000密歇根州居民的公众受众。光通用是在碳纤维固定的初始碳纤维时，与碳纤维的初始载体相结合时，碳的第二大代谢通量是第二大的代谢通量必须回收的分子。 Calvin-Benson循环以碳的巨大成本中间。了解光呼吸过程中二氧化碳释放的机制对于预测植物对气候变化的反应以及具有提高的碳同化和生产力的潜在工程植物的反应至关重要。当温度升高时，光呼吸会每次rubisco氧合释放更多的二氧化碳，但是这种增加的机制尚不清楚。该提案的目的是通过代谢建模，体内气体交换和同位素标记方法的创新组合在高温下解决这种过量的二氧化碳释放的机制。该提议的中心假设是，当中间体在过氧化酶与光刺激产生的过氧化氢中反应在过氧化酶中反应时，二氧化碳的释放过多。该假设假设在环境温度下，过氧化氢是通过酶过氧化酶有效排毒的，但是在升高的温度下，过氧化氢酶无法迅速去除过氧化氢以最大程度地减少非酶脱羧反应。该项目的结果将跨越纪律界限，具有改善碳循环的地球系统模型的强大潜力，并确定将光合作用适应现实世界增长状况的关键特征。这项奖项反映了NSF的法定任务，并通过使用该基金会的知识分子优点和广泛的影响来评估NSF的法定任务，并被视为诚实的支持。