Database Product Description
- Host Organism
- Glycine max L. (Soybean)
- Glyphosate herbicide tolerance.
- Trait Introduction
- Microparticle bombardment of plant cells or tissue
- Proposed Use
- Production of soybeans for animal feed (mostly defatted toasted meal and flakes) and human consumption (mostly oil, protein fractions, and dietary fibre).
- Product Developer
- Monsanto Company
Summary of Regulatory Approvals
Summary of Introduced Genetic Elements Expand
Characteristics of Glycine max L. (Soybean) Expand
Donor Organism Characteristics Expand
Modification Method Expand
Characteristics of the Modification Expand
Environmental Safety Considerations Expand
Food and/or Feed Safety Considerations Expand
Soybean (Glycine max) is grown primarily for its seed, which has many uses in the food and industrial sectors, and represents one of the major sources of edible vegetable oil and of proteins for livestock feed use. The major producers of soybeans were the United States, Brazil, Argentina, China, India, Paraguay and Canada.
A major food use of soybean in North America and Europe is as purified oil, used in margarines, shortenings, and cooking and salad oils. It is also a major ingredient in food products such as tofu, tempeh, soya sauce, simulated milk and meat products, and is a minor ingredient in many processed foods. Soybean meal is used as a supplement in feed rations for livestock.
Weeds are a major production problem in soybean cultivation. Typically, weeds are managed using a combination of cultural (e.g. seed bed preparation, using clean seed, variety selection, and planting date) and chemical controls. Depending on the production area and the prevalent weed species, herbicides may be applied before planting (e.g. pendimethalin, trifluralin, metribuzin), after planting but before emergence (e.g. pendimethalin, linuron, imazethapyr), and/or after emergence (e.g. bentazon, acifluorfen, fomesafen). Commonly, several different herbicides are required to adequately control weeds in soybean fields.
The soybean line GTS 40-3-2 was developed to allow for the use of glyphosate, the active ingredient in the herbicide Roundup®, as a weed control option. This genetically engineered soybean line contains a form of the plant enzyme 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) that allows GTS 40-3-2 to survive the otherwise lethal application of glyphosate. The EPSPS gene put into GTS 40-3-2 was isolated from a strain of the common soil bacterium Agrobacterium tumefaciens called CP4 and the form of EPSPS enzyme produced by this gene is tolerant to glyphosate.
The EPSPS enzyme is part of an important biochemical pathway in plants called the shikimate pathway, that is involved in the production of aromatic amino acids and other aromatic compounds. When conventional plants are treated with glyphosate, the plants cannot produce the aromatic amino acids needed to grow and survive. EPSPS is present in all plants, bacteria, and fungi. It is not present in animals, which do not synthesize their own aromatic amino acids. Because the aromatic amino acid biosynthetic pathway is not present in mammals, birds or aquatic life forms, glyphosate has little if any toxicity for these organisms. The EPSPS enzyme is naturally present in foods derived from plant and microbial sources.
GTS 40-3-2 was developed by introducing the CP4 EPSPS gene into a commercial soybean variety using particle-acceleration (biolistic) transformation. The glyphosate tolerance trait expressed in GTS 40-3-2 has since been transferred into more than one thousand commercial soybean varieties by traditional breeding techniques.
GTS 40-3-2 has been tested in field trials in the United States, Central and South America, Europe, Central Europe and Canada since 1991. Data collected from over 150 field trials conducted over a three-year period prior to commercialization in the United States demonstrated that GTS 40-3-2 did not differ significantly from conventional soybeans in morphology, seed production (yield), agronomic characteristics (such as time to flowering and pod set, or vigor) and tendency to weediness. GTS 40-3-2 did not negatively affect beneficial or nontarget organisms, and was not expected to impact on threatened or endangered species.
Soybean does not have any weedy relatives with which it can crossbreed in the continental United States and Canada. Cultivated soybean can naturally cross with the wild annual species G. soja, however G. soja, which occurs naturally in China, Korea, Japan, Taiwan and the former USSR, is not naturalized in North America. Additionally, soybean plants are almost completely self-pollinated and reproductive characteristics such as pollen production and viability were unchanged by the genetic modification resulting in GTS 40-3-2. It was therefore concluded that the potential for transfer of the glyphosate tolerance trait from the transgenic line to soybean relatives through gene flow (outcrossing) was negligible in managed ecosystems, and that there was no potential for transfer to wild species in Canada and the continental United States.
The food and livestock feed safety of GTS 40-3-2 soybean was established based on: the evaluation of the similarity of the structure and function of CP4 EPSPS protein to this same enzyme naturally present in foods and livestock feeds; the fact that CP4 EPSPS protein constitutes a small amount of the protein in GTS-40-3-2 soybeans so there is little dietary exposure; the lack of toxicity or allergenicity of EPSPS proteins from plants, bacteria and fungi; and by direct laboratory studies of the CP4 EPSPS protein. The nutritional equivalence and wholesomeness of GTS 40-3-2 soybeans compared to conventional (non-GM) soybeans was demonstrated by the analysis of key nutrients, including proximates (e.g. protein, fat, fibre, ash, and carbohydrates), amino acid and fatty acid composition, as well as anti-nutrients. A number of these parameters were also measured in glyphosate-treated soybeans. The equivalence of GTS 40-3-2 soybeans to conventional soybeans was confirmed in numerous feeding studies with rats, fish, broiler chickens, quail, and cows.
Links to Further Information Expand
This record was last modified on Monday, January 13, 2014