Genetically modified (GM) soy refers to soybean plants with altered genetic material, typically by introducing specific genes from other organisms into the soybean’s DNA. This modification aims to give the plant new, desirable characteristics, such as resistance to herbicides or pests.
Understanding Genetic Modification
Genetic modification involves manipulating an organism’s DNA. DNA, or deoxyribonucleic acid, is the hereditary material found in almost all living organisms, carrying the instructions for development and functioning. Genes are specific segments of DNA that serve as the basic physical and functional units of heredity. They contain the instructions for making proteins or controlling other genes. Genetic modification works by identifying a gene for a desired trait in one organism and then transferring that gene into the DNA of another organism. This process allows the recipient organism to express the new trait.
Methods for Modifying Soy
The primary techniques used to genetically modify soy involve two main approaches: Agrobacterium tumefaciens-mediated transformation and gene gun technology. Both methods aim to deliver new genetic material into soybean cells, which can then grow into a whole plant expressing the desired trait.
Agrobacterium tumefaciens-mediated transformation leverages a natural process. Agrobacterium tumefaciens is a soil bacterium that can naturally transfer a segment of its own DNA, called T-DNA, into the genome of plant cells. Scientists modify this bacterium by removing the genes that cause plant tumors and inserting the desired genes into the T-DNA region of its plasmid, a small, circular piece of DNA. The modified Agrobacterium is then introduced to soybean plant tissue. The bacterium infects the plant cells and transfers the engineered T-DNA into the plant’s chromosomes.
The gene gun, also known as biolistic technology or particle bombardment, offers a physical method for gene delivery. This technique involves coating microscopic particles with the DNA containing the desired gene. These DNA-coated particles are then propelled at high velocity into plant cells, physically penetrating the cell walls and membranes. Once inside the cell, the introduced DNA can integrate into the plant’s own genome.
After either transformation method, the plant cells that have successfully incorporated the new gene are selected, often using a marker gene that confers resistance to an antibiotic or herbicide. These selected cells are then regenerated into whole soybean plants through tissue culture, ensuring that the new trait is present in every cell of the resulting plant. The regenerated plants are then grown and monitored to confirm the stable integration and expression of the introduced gene.
Traits Introduced in GM Soy
Soy is genetically modified to introduce traits that benefit agricultural production, focusing on improved weed and pest management, with one of the most common being herbicide tolerance, notably to glyphosate, the active ingredient in herbicides like Roundup. These genetically modified soybeans, often referred to as “Roundup Ready” soy, contain a gene from a soil microorganism that produces an enzyme resistant to glyphosate. This allows farmers to spray glyphosate to control weeds without harming the crop. This tolerance enables more efficient weed control, as a broad-spectrum herbicide can be applied over the growing crop, reducing competition from weeds and potentially improving yields.
Another trait introduced into some GM soy varieties is insect resistance. This is achieved by incorporating genes from the bacterium Bacillus thuringiensis (Bt), which produce proteins that are toxic to specific insect pests. While Bt soy varieties have been developed and commercialized in some regions, such as South America, their adoption in other areas like the U.S. has faced considerations related to pest resistance development and market demand. The presence of these insecticidal proteins reduces the need for external insecticide applications, protecting the crop from damage.
Bringing GM Soy to Market
Bringing genetically modified soy from the laboratory to commercial availability involves a multi-stage process. After successful genetic modification and initial laboratory confirmation, the modified soy plants undergo extensive testing. This includes greenhouse trials to verify the stability and expression of the introduced trait. Plants demonstrating consistent performance are then moved to controlled field trials to assess their characteristics under agricultural conditions.
Throughout this development, GM soy undergoes rigorous safety and environmental impact assessments. Regulatory authorities worldwide evaluate the potential effects on human and animal health, as well as the environment, before a GM crop can be approved for cultivation or use in food and feed. These assessments examine the molecular characteristics of the modified plant, compare its composition and agronomic properties to conventional counterparts, and analyze any potential allergenic or toxicological concerns. The regulatory phase is typically the longest part of the development process, often taking several years. Only after meeting stringent safety and regulatory requirements can GM soy be released to farmers for commercial planting.