To increase soybean value for the entire value chain, selection of soybean germplasm and identification of soybean genes controlling protein synthesis and storage along with the development of markers for those genes, provide the opportunity to create soybeans with higher protein levels and will aid in the development of commercial soybean varieties with an improved nutritional bundle. The amount and quality of seed proteins depend on the biosynthesis of amino acids, especially the essential sulfur-containing amino acid methionine, and how much amino acids are finally incorporated into storage proteins. The proposed research project will employ a “push-pull” approach to improve protein-bound Met levels in soybean seeds. We will ‘push’ free Met levels by engineering biosynthetic pathways for this amino acid and also ‘pull’ Met by creating storage proteins with increased number of codons for Met inclusion. In addition, these two Met traits (i.e., increased free Met and expression of Met-rich storage proteins) will be combined with knock-out mutations in 7S (conglycinins) storage proteins. Our working hypothesis is that stacking these three Met traits using modern technologies and paradigms, such as CRISPR/Cas9, gene modeling and protein re-balancing, could overcome the major factors limiting successful improvement of soybean protein quality. Lastly, to determine if altering Met metabolism will affect plant growth and seed composition, this proposal will also measure growth and yield parameters, as well as the accumulation of other amino acids, protein, oil and sucrose associated with the introduced Met traits.