9602190 Hughes The long term goal of this proposal is to thoroughly understand the regulatory mechanisms controlling the biosynthesis of the essential amino acid, methionine, in plants, especially soybean that has a low methionine content. This knowledge may enable us to determine how to alter these regulatory mechanisms to develop nutritionally improved plants that produce increased levels of methionine. The major goals are focussed on an important enzyme involved in methionine biosynthesis, cystationine gamma-synthase (CS), and its gene and/or gene family in soybean. CS is the branch point enzyme leading to methionine production from aspartate. In order, to understand the molecular and metabolic mechanisms that regulate methionine systhesis, the following specific aims will be addressed: I. What is the role of cystathionine gamma-synthase in methionine systhesis? II. What regulates the expression of the gene encoding cystathionine gamma-synthase? Plants are the major source of dietary proteins for umans and livestock. The essential amino acid content of these dietary proteins is very important because these amino acids are necessary to ensure proper growth in humans and livestock that are unable to synthesize them. Therefore, these amino acids are usually supplemented into their diets.
