Quantifying plant phenotypes with isotopic labeling and metabolic flux analysis

Authors: Allen, Douglas - Doug

Submitted to: Current Opinion in Biotechnology
Publication Type: Review Article
Publication Acceptance Date: 9/2/2015
Publication Date: 2/1/2016
Publication URL: http://handle.nal.usda.gov/10113/62952
Citation: Allen, D.K. 2016. Quantifying plant phenotypes with isotopic labeling and metabolic flux analysis. Current Opinion in Biotechnology. 37:45-52. doi:10.1016/j.copbio.2015.10.002.

Interpretive Summary: Agricultural productivity centers around the amount of harvestable biomass obtained from crops. Biomass is produced by the plant through metabolism that converts sugars and amino acids into lipids, protein, starch and cell wall that are the primary components of most tissues. The reactions necessary for these interconversions are complicated, distributed across multiple locations in plant cells, and in some cases the participating reactions are not well characterized. In addition the use of enzymes in different tissues such as roots, seeds and leaves can vary and is dependent upon the supply of nutrients, the availability of resources such as light and carbon dioxide or oxygen and environmental parameters like temperature. One of the few tools that can assess the operation of these networks is metabolic flux analysis. Metabolic flux analysis combines isotopic tracer experiments with computational analyses to establish the use of different metabolic pathways in plants. Here we describe recent progress including studies that inspect nutrient deprivation and recent advances in methodology. Research that aims to quantify the use of metabolic pathways is important because it can guide metabolic engineering strategies to alter biomass composition or increase yield.

Technical Abstract: Analyses of metabolic flux using stable isotopes in plants have traditionally been restricted to tissues with presumed homogeneous cell populations such as developing seeds, cell suspensions, or cultured roots and root tips. It is now possible to describe these and other more complex tissues such as leaves and in more depth using novel methods in mass spectrometry, isotope labeling strategies, and transient labeling-based flux analyses. Such studies are necessary for a systems level description of plant function that more closely represents biological reality, and provides insights into the genes that will need to be modified as natural resources become ever more limited and environments change.