Metabolome is the complete set of small molecules within one organism, and metabolomics is the study of small molecules in a cell or biological system. According to metabolic pathway, small molecules can be classified as primary and secondary. On one side, small molecules are products of proteins made from genes. On the other side, they are the end phenotype distinguished as a valued commodity such as an oil, carbohydrate or essential nutrient like beta carotene. Two essential elements in the study of metabolomics are the chemical composition of metabolome, the connectivity among small molecules. The flux of these molecules within a plant cell is a key to commodity production but can also describe cellular physiological developmental and physiological responses to the environment. Developments in informatics, flux analysis and biochemical modeling are adding new dimensions to the field of metabolomics. Metabolomics has direct relevance not only to fundamental biological studies, but also to areas such as nutrition, crop quality traits, drug discovery and diagnostics.
Even though several genomic research projects are addressing molecular genetics of soybean seed composition and yield, an understanding of the metabolites associated with these traits is lacking. The NCSB scientists have taken initiative to profile and identify secondary metabolites, small molecules and small peptides from soybean seeds through a combination of fingerprinting and target analysis methods. Major research objectives of these efforts are: a) to develop soybean metabolic fingerprinting technologies for the identification of potential compounds and small molecules for human health and nutrition, and b) to establish a comprehensive set of chemical standards for soybean metabolites moving toward construction of a metabolome map with a focus on seed and the drought effects on seed development.
At NCSB, based on existing research efforts on soybean metabolomics, complete and validated state-of-the-art chromatographic and detection procedures will be used to analyze, identify and quantify large numbers of soybean small molecules with GC/MS and LC/MS methods. We are in the process of acquiring a state-of-art high resolution and high throughput LC/MS system, which will greatly facilitate the metabolomics and proteomics efforts. Since no single analytical procedure identifies all molecules in a plant, multiple methods will be used to identify and catalogue targets. For novel metabolite identification, in conjunction with LC/MS methods, purification and offline-NMR spectroscopy will be used for structural elucidation in cooperation with NMR facilities in the Department of Chemistry at MU. Development of high resolution LC/MS procedures for metabolite profiling and the identification of small molecules using these procedures are also under way at NCSB member labs. Research efforts to build metabolome database of soybean, compromised by spectra data, retention time indexes, together with temporal and spatial distribution information is in progress at NCSB. By performing parallel analyses on different tissues with targeted and non-targeted analysis, it will be possible to distinguish the presence or absence of small molecules and associate the small molecule accumulation profiles with a specific tissue, developmental time point or stress response. Flux analysis with stable isotope labeling will be employed for addressing changes in key metabolic pathways underlying stress responses, such as temperature-regulated oleic acid composition in soybean seeds.