Updated February 1, 2021:
Soybeans are primarily used for animal feed and as a source of vegetable oil. Though defatted soybean meal is the ‘gold standard’ source of protein for most animal feeds, it has less than needed amounts of sulfur-containing amino acids, cysteine and methionine. The overarching goal of this project is to develop soybean plant by improving incorporation of sulfur-containing amino acids in protein at the expense of other uses for sulfur that may be important for other parts of the plant but less crucial to the developing seed. Genetic and biochemical approaches are being used to manipulate the activity of enzymes that are responsible for amino acid composition and characterize the changes in metabolism and other biomass components. A number of lines were analyzed compositionally including, lipid and protein levels, and protein amino acid composition that impacts protein quality. Improved methods for analysis of sulfur metabolic intermediates were developed on a new, more sensitive instrument. Molecular biology was used to construct the plant transformation vectors used to genetically engineer soybeans for value-added amino acid compositions with altered sulfur content.