CHE 598 Seminar: Using Metabolic Flux Analysis To Discover The Fundamental Links Between Photosynthesis And Plant Metabolism
About the event
SPEAKER: Dr. Berkley Walker, Associate Professor, Michigan State University
BIOGRAPHY:
Berkley Walker studies the multi-scale impact and mechanisms of photosynthesis…with a special emphasis on how photorespiration interacts with central metabolism and plant nutrition. While always interested in science, he original set off to be an entrepreneur, founding an energy bar company in high school and running it while earning an undergraduate degree in microbiology. After undergraduate studies and a stint as a product manager for an instrumentation company he decided that the scientists have all the real fun and returned to graduate school. He received his PhD at Washington State University and postdoctoral training with the United States Department of Agriculture at the University of Illinois before accepting an Alexander von Humboldt fellowship to Heinrich-Heine University in Duesseldorf, Germany. He is currently an associate professor in the Department of Energy-Michigan State University Plant Research Laboratory. He is a respected researcher and has published over 50 peer-reviewed journal articles, submitted a patent for an improvement to photosynthesis and given over 50 oral presentations domestically and internationally. He receives funding from multiple Department of Energy programs and currently holds two National Science Foundation grants to support the fantastic researchers in his lab.
ABSTRACT:
Photorespiration is a key component of plant metabolism that recycles inhibitory metabolites produced as a byproduct when the CO2-fixing enzyme, rubisco, reacts with oxygen instead of CO2. Because of photorespirations sensitivity to CO2 concentrations and temperature, it is an important driver of plant response to climate change. Photorespiration requires 30-40% of photosynthetic energy in illuminated leaves and releases carbon dioxide, greatly reducing rates of net carbon assimilation in many plant species and comprising a large portion of total metabolic flux. Photorespiration has been a perennial target for crop improvement, but many questions about its in vivo function remain unresolved. For example: What is the role of photorespiration in photoprotection? What is the temperature response of the photorespiratory pathway itself, and how does well does it adapt? Do photorespiratory intermediates, like glycine and serine, proceed according to the “textbook pathway” or are they diverted to support amino acid synthesis in planta? and, Does the large flux of carbon in photorespiration supply other aspects of metabolism like one-carbon synthesis? The answers to these questions are important for designing “next generation” improvement strategies for photorespiration and for understanding the fundamental responses of plants to future climates. Here I discuss our progress addressing these questions using gas exchange measurements, biophysical measures of photosynthetic energy use, metabolic flux analysis, and reaction-kinetic simulations of photorespiration.