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

Washington State University, Pullman WA

Investigators

Abstract

This project explores the intersection between photorespiration and one carbon metabolism, two plant biochemical pathways that are of critical importance to plant growth and consequently human nutrition. Photorespiration is a plant process that recycles toxic products created as a byproduct of photosynthesis and is an essential process of plant growth. Rates of photorespiration are linked to elevated temperature 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 generate models predicting how current and future climatic conditions influence plant performance and yields. These models would inform breeding and engineering 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 are taught integrative approaches to plant biology, broadening their education and learning opportunities in collaborative scientific research. The aim of this activity is to instill positive attitudes towards science, and encourage creative and critical thinking by providing trainees with greater access to the scientific process early in their educational training. Underrepresented undergraduate and graduate students participate in several university programs designed to provide information on existing research opportunities to underrepresented groups at Washington State University 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 metabolism 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 determine 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, metabolite analyses, and labeling-assisted metabolic flux analysis are used to test the role of these two enzymes 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.