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Xinyu Fu (Walker lab)

Date & Location: October 15, 2019, at 12p; Room 168 Plant Biology Building

Subject: Quantifying Fluxes Through Photosynthetic Metabolism Using 13CO2-Tracers

Abstract: Metabolic flux is the output of the integrated interactions between genes, proteins, and metabolites at the network level, and thus provides an accurate representation of the physiological states of plants. Quantifying fluxes through the plant metabolic network is critical to predict or validate the metabolic consequences of genetic manipulation and environmental perturbations. Recent advances in stable-isotope-assisted metabolomics and computational modeling have enabled us to resolve metabolic fluxes through photosynthetic metabolism using 13CO2 as a tracer. Challenges pertaining to this emerging technology include 1) establishment of a labeling cuvette with precise control of 13CO2 concentration, 2) capacity to quench tissues quickly to analyze metabolites with turnover times in the order of seconds or less, 3) multiple analytical platforms are required to quantify the isotopic patterns in central metabolites, and 4) determination of appropriate time points to describe the dynamic labeling process before central metabolites are uniformly 13C-labeled.

To address these challenges, we have designed a gas exchange cuvette with custom gas mixing system and a cryospray quenching system. Our aim is to integrate metabolic flux analysis with leaf-level gas exchange measurements to quantify the fluxes through photosynthesis and photorespiration in response to changing environments. Our long term goal is to identify optimization strategies to increase carbon assimilation rates.

Speaker Lab: Dr. Berkley Walker