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Contribution to Book
Molecular Genetic Control of Protein Composition and Quality in Soybean
Designing value-added soybeans for markets of the future (1991)
  • M. P. Scott, United States Department of Agriculture
  • W. J. P. Lago, United States Department of Agriculture
  • N. C. Nielsen, United States Department of Agriculture
Soybean meal is an important source of vegetable protein. However, problems such as amino acid balance, digestibility and antigenic properties tend to diminish its nutritional quality. This report summarizes our progress toward improving the amino acid balance of soybean protein. Our work has employed a molecular genetic approach to add sulfur-containing amino acids within the structure of the glycinin family of seed storage proteins, which comprise the majority of the protein in soybean seed. Through this approach, modifications in glycinin proteins are made by altering cloned cDNAs encoding glycinin subunits. Then these cDNAs are used to drive an in vitro transcription/translation system. Subsequently, the proteins made in this system are tested for ability to
assemble into complexes that are similar to those that occur in the seed. This system has been used to identify a hypervariable region in the protein that tolerates extensive deletions or insertions, and other regions in the subunits where conservative point mutations can be made. Using this information, a series of modified glycinin genes have been constructed that encode subunits with increased amounts of sulfur amino acids. Several of these constructs are expressed in transgenic tobacco plants resulting in the accumulation of modified
proteins in the seed. Therefore, we expect that insertion of these modified genes in soybean lines that lack undesirable glycinin subunits should result in considerable improvement of seed protein quality.
Publication Date
Richard F. Wilson
American Oil Chemists' Society
Publisher Statement
Works produced by employees of the U.S. Government as part of their official duties are not copyrighted within the U.S. The content of this document is not copyrighted.
Citation Information
M. P. Scott, W. J. P. Lago and N. C. Nielsen. "Molecular Genetic Control of Protein Composition and Quality in Soybean" Champaign, IllinoisDesigning value-added soybeans for markets of the future (1991) p. 91 - 101
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