Updated November 18, 2020:
So far, extensive efforts to fortify soybean with sulfur-containing amino acids, specifically methionine, have had very limited success. In this project, we employed a potentially promising “push-pull” approach, which will both ‘push’ methionine levels by engineering biosynthetic pathways for this amino acid and also ‘pull’ free methionine by creating storage proteins with increased number of codons for methionine inclusion. The end goal of the proposed “push-pull” approach is to alter seed metabolism to favor the production of seed storage proteins enriched in sulfur-containing codons.
To implement this approach, we developed novel soybean genotypes with these three traits: (1) production of high free Methionine; (2) production of reduced Methionine-poor 7S and increased Methionine-rich 11S storage proteins; and (3) production of modified 11S (i.e., GY1) storage proteins with increased Methionine codons. These soybean genotypes were developed by exploiting the sequenced soybean genome, published information on Methionine metabolism and multiplexed genome editing by CRISPR/Cas9.