LC/MS coupled to PODIUM establishes the amino acid metabolomes of Sorghum bicolor.

Untargeted metabolomics is a well-known and reliable method to globally profile small molecules. A number of analytical tools can be used to accomplish this goal, but liquid chromatography mass spectrometry (LC/MS) is most often used due to its precision and sensitivity. Although the use of LC/MS results in large amounts of data, much of it is difficult and time consuming to analyze. Most importantly, LC/MS cannot conclusively identify small molecules; additional analytical tools are needed to address these limitations. Effort has been put into streamlining the analysis of data from LC/MS in untargeted metabolomics with recently created analytical pipelines like XCMS, CAMERA, and PODIUM. The advent of these technologies makes it possible to efficiently analyze large amounts of data and conclusively identify small molecules, thus expanding our knowledge of metabolites and their role in various biochemical pathways. In this research, we attempted to use PODIUM to analyze the data from an untargeted metabolomics experiment in order to identify metabolites derived from amino acids. The aim of the experiment had two parts: (1) to feed Sorghum bicolor seedlings with isotopically labeled amino acids and analyze them using PODIUM and (2) to tentatively identify small molecules derived from the amino acids. To do this, plants were fed individually with one of 15 amino acids, which were expected to be direct precursors for natural products. These amino acids were labeled with Carbon-13 ( C) so that labeled products could be distinguished and traced back to their precursor amino acid. Metabolites were quantified by identifying isotope peak pairs using LC/MS and the PODIUM analytical pipeline. Carbon-12 ( C) amino acids were also fed as controls. Overall, this research will utilize PODIUM to identify metabolites and will determine the relationship between metabolites and the amino acids responsible for their synthesis.