Engineering Soybean for Enhanced Sulfur Amino Acid Content

Abstract

Soybean [Glycine max (L.) Merr.] is an important protein source in human diets and animal rations. Additionally, human consumption of soybean protein is reported to provide specific health benefits. Since methionine and cysteine contents limit the nutritional value of soybean, efforts involving both traditional breeding and genetic engineering have been employed in attempts to increase the presence of these essential amino acids. Traditional breeding has been primarily utilized to increase the total protein content but not to enhance the sulfur amino acid content of soybean. Although mutagenesis in conjunction with traditional breeding is a viable approach for enhancing the sulfur amino acid content of soybean, genetic engineering appears to be a more realistic approach. Introduction of methionine‐rich heterologous proteins has resulted in a modest increase of this amino acid in soybean. Either elevating the expression of endogenous methionine‐rich proteins or introducing synthetic proteins containing a high percentage of essential amino acids are other possible approaches that may increase the nutritional quality of the seed. Even though considerable progress has been made in enhancing the methionine content of soybean, several obstacles remain. A thorough understanding the sulfur assimilatory pathway in soybean is a prerequisite for improving the sulfur amino acid content. Expression of feedback‐insensitive forms of serine acetyl transferase and O‐acetylserine (thiol) lyase, two key enzymes in sulfur assimilatory pathway, could lead to an increase in the availability of sulfur amino acids. An adequate supply of sulfur amino acids in developing seeds may facilitate accumulation of sulfur‐rich proteins to a level sufficient to meet the nutritional requirement of livestock and poultry.

Do genetically modified crops affect animal reproduction? A review of the ongoing debate

“…On the other hand, more and more types of genetic materials and the systems for GM crops have been created, accompanying the improvement in genetic engineering. These include soybean with improved amino acid composition or potato with enhanced calcium content and other functional foods (Krishnan, 2005;Park et al, 2005;Hirschi, 2009). Owing to the development of GM crops, they are today distributed all over the world, frequently becoming part of human and -E-mail: fxshi@njau.edu.cn animal diets (Sanvido et al, 2007).…”

Allelopathic Behaviour of Cyperus Rotundus L. On Both CHORCHORUS OLITORIUS (BROAD LEAVED WEED) AND ECHINOCHLOA CRUS-GALLI (GRASSY WEED) ASSOCIATED WITH SOYBEAN

“…This characteristic separates it from the other types of pulses. Soybean is an excellent source of protein (Krishnan 2005). Soybean contains the chemical known as "Westin" Lecithin known to help break down the cholesterol in the blood (Polichett et al 1996).…”

Using Genomics to Study Legume Seed Development

“…For example, soybean (Glycine max) is now one of the most important seed crops in the world (Wilcox, 2004). Research on legume seed development has led to direct applications, such as seeds with more nutrients (Kinney, 1998;Wang et al, 2003;Krishnan, 2005), reduced allergens (Herman et al, 2003), and novel constituents, such as edible vaccines (Moravec et al, 2007). In the current genomic era, it is now possible to begin to understand what genes are required to make a legume seed and how regulatory networks are interconnected in legume genomes to program seed formation.…”