Collaborative Research: Investigating the Role of Cytosolic One-carbon Metabolism in Photorespiration

本项目将探索光呼吸和单碳代谢之间的交集，这两种植物生化途径对植物生长和人类营养至关重要。光呼吸是一种植物循环利用光合作用产生的有毒产物的过程，是植物生长所必需的重要过程。光呼吸速率与温度和二氧化碳浓度的增长有关，这意味着未来的光呼吸速率将随着气候的变化而变化。碳代谢对植物生长同样至关重要，也是叶酸等必需维生素的来源。该项目的目标是帮助建立预测当前和未来气候条件如何影响植物性能和产量的模型，并为育种和工程方法提供信息，以优化植物生产力和对人类营养和健康重要的植物化合物的生产。在这个跨学科的项目中，将向高中、本科生、研究生和博士后学员讲授植物生物学的综合方法，拓宽他们在合作科学研究中的教育和学习机会。其目的是灌输对科学的积极态度，鼓励创造性和批判性思维，让受训者在他们的教育培训早期有更多的机会接触科学过程。未被充分代表的本科生和研究生的参与将通过参加几个大学项目来完成，这些项目旨在向华盛顿州立大学和密歇根州立大学的未被充分代表的群体提供有关现有研究机会的信息。这个项目的主要面向公众的推广活动是在华盛顿州立大学举办的科学之声表演，这是一个独特的植物科学家和音乐家之间的合作，产生了一个ted式的活动，旨在提高人们对植物科学重要性的认识。传统上，光呼吸被认为是有明确定义的，代谢灵活性很小。然而，PI最近的工作表明，光呼吸通量可以选择性地划分为细胞质中四氢叶酸结合的一碳（C1）单位的代谢。这可能为传统的光呼吸途径提供了一个溢出，并对光呼吸、光合作用和叶面氮同化的能量学和碳平衡具有重要意义。因此，确定胞质C1代谢对光呼吸的贡献是很重要的，特别是在对影响光呼吸速率的条件（如干旱和高温）的响应中。该项目的目标是确定胞质C1代谢在光呼吸中的作用。据推测，两种细胞质C1酶，甲酸-四氢叶酸连接酶和丝氨酸羟甲基转移酶，参与光呼吸过程中产生的甲酸和丝氨酸的加工。反向遗传学、叶片气体交换、代谢生命分析和标记辅助代谢通量分析将用于测试这两种酶在C1和光呼吸途径之间碳代谢协调中的作用。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This project will explore the intersection between photorespiration and one carbon metabolism, two plant biochemical pathways that are of critical importance to plant growth and human nutrition. Photorespira-tion is a plant process that recycles toxic products created as a byproduct of photosynthesis and is an essential process needed by the plant to grow. Rates of photorespiration are linked to growing tempera-ture and carbon dioxide concentration, meaning that future rates of photorespiration will change with changing climates. One carbon metabolism is similarly vital to plant growth, and also is the source for essential vitamins like folate. The goal of this project is to help generate models predicting how current and future climatic conditions influence plant performance and yields, and inform breeding and engineer-ing approaches to optimize plant productivity and the production of plant compounds important for human nutrition and health. During this interdisciplinary project, high school, undergraduate, graduate, and post-doctoral trainees will be taught integrative approaches to plant biology, broadening their education and learning opportunities in collaborative scientific research. The aim is to instill positive attitudes towards science, and encourage creative and critical thinking by providing trainees with greater access to the sci-entific process early in their educational training. Participation of underrepresented undergraduate and graduate students will be accomplished by taking part in several university programs designed to provide information on existing research opportunities to under-represented groups at Washington State Universi-ty and Michigan State University. The main public-facing outreach activity of this project is a Sounds of Science performance at Washington State University, a unique collaboration between plant scientists and musicians resulting in a TED-talk styled event aimed to increase awareness of the importance of plant science. Traditionally, photorespiration has been considered well defined with little metabolic flexibility. However, the PI’s recent work suggests that photorespiratory flux can alternatively be partitioned into the metabo-lism of tetrahydrofolate-bound one-carbon (C1) units in the cytosol. This may provide an overflow for the traditional photorespiratory pathway and has important implications for the energetics and carbon balance of photorespiration, photosynthesis, and foliar nitrogen assimilation. Therefore, it is important to define the contribution of cytosolic C1 metabolism to photorespiration, particularly in response to conditions that influence rates of photorespiration (e.g. drought and high temperature). The goal of the project is to de-termine the role of cytosolic C1 metabolism in photorespiration. It is hypothesized that two cytosolic C1 enzymes, formate-tetrahydrofolate ligase and serine hydroxymethyltransferase, participate in processing of formate and serine generated during photorespiration. Reverse genetics, leaf gas exchange, metabo-lite analyses, and labeling-assisted metabolic flux analysis will be used to test the role of these two en-zymes in the coordination of carbon metabolism between the C1 and photorespiratory pathways.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.