Comparative Metabolomics Analysis of Seed Composition Accumulation in Soybean (Glycine max L.) Differing in Protein and Oil Content

Efforts to enhance protein and oil contents in soybean seeds are significant; however, a negative correlation usually exists between protein and oil levels. This observation emphasizes the need to understand the spatiotemporal dynamics and interactions in protein and oil accumulation during soybean seed development. The current study used LC-MS/MS methodology to conduct high-throughput metabolomic analyses, aiming to understand metabolite compositions and spatial distributions in soybean varieties with extreme protein and oil content phenotypes including HPHO, HPLO, LPHO and LPLO lines. Comparative investigations revealed distinct variances in the metabolic characteristics of these four lines. Key metabolites associated with oil and protein synthesis were screened out using these data and included glucose, citric acid, α-ketoglutaric acid, glycerate 3-phosphate, glyceraldehyde 3-phosphate, succinic acid, cis-aconitic acid. Pathway analyses of differentially abundant metabolites indicated significant increases in the activity of the Calvin cycle, TCA cycle, glycolysis, and shikimic acid pathways. Simultaneously, reductions were observed in pathways related to the conversion of glucose into pentose, ascorbate and aldarate. This modification supports incorporating carbon sources into amino and fatty acid synthesis pathways in protein- and oil-rich soybean seeds. These results provide a basis for future initiatives to develop soybean cultivars with enhanced protein and oil yields.