DAS-44406-6

DAS-44406-6 is a genetically engineered soybean that has had its DNA modified to withstand all broadleaf herbicides in the phenoxy auxin group (such as 2,4-D) as well as the herbicides glyphosate and glufosinate. It is made by Dow AgroSciences LLC, which petitioned the USDA to deregulate (legalize) DAS-44406-6 in October 2011. 2,4-D Soybeans such as this one are highly controversial, as 2,4-D was one of the chemicals in Agent Orange.

2011: Petition for Deregulation
On October 19, 2011, Dow AgroSciences petitioned the USDA to deregulate DAS-44406-6. The petition describes the soybean as follows:


 * "DAS-444Ø6-6 soybean is a transgenic soybean product that provides tolerance to the herbicides 2,4-dichlorophenoxyacetic acid (2,4-D]), glyphosate and glufosinate. This herbicide-tolerant soybean will provide growers with greater flexibility in selection of herbicides for the improved control of economically important weeds; allow an increased application window for effective weed control; and provide an effective weed resistance management solution to the increased incidence of glyphosate resistant weeds.


 * "DAS-444Ø6-6 soybean plants have been genetically modified to express the aryloxyalkanoate dioxygenase-12 (AAD-12), double mutant 5-enolpyruvylshikimate-3-phosphate synthase (2mEPSPS), and phosphinothricin acetyltransferase (PAT) proteins. The AAD-12 protein is an enzyme with an alpha ketoglutarate-dependent dioxygenase activity which results in metabolic inactivation of the herbicides of the aryloxyalkanoate family. The aad-12 gene, which expresses the AAD-12 protein, was derived from Delftia acidovorans, a gram-negative soil bacterium. The 2mEPSPS protein has a decreased sensitivity to the herbicide glyphosate, allowing the enzyme to function in the presence of the herbicide and thereby making the plant tolerant to glyphosate. The 2mEPSPS protein is encoded by a modified version of the epsps gene from corn (Zea mays). The PAT enzyme acetylates the primary amino group of phosphinothricin rendering it inactive. The pat gene expressing the PAT protein was derived from Streptomyces viridochromogenes.


 * "The aad-12, 2mepsps and pat genes were introduced into DAS-444Ø6-6 soybean using Agrobacterium-mediated transformation. Molecular characterization by Southern blot analyses of DAS-444Ø6-6 soybean confirmed that a single, intact DNA insert containing the aad-12, 2mepsps and pat gene expression cassettes was stably integrated into the soybean genome. Southern blot analyses also confirmed the absence of the plasmid backbone DNA in DAS-444Ø6-6 soybean. The integrity of the inserted DNA was demonstrated in five different breeding generations. Data from segregating generations confirmed the predicted Mendelian inheritance pattern. These data confirmed the stability of DAS-444Ø6-6 soybean during traditional breeding procedures.


 * "The AAD-12, 2mEPSPS and PAT proteins in DAS-444Ø6-6 soybean were characterized biochemically and measured using protein-specific enzyme linked immunosorbent assays (ELISA). Protein expression was analyzed in leaf, root, whole-plant and grain tissues collected throughout the growing season from DAS-444Ø6-6 soybean plants treated with 2,4-D, glyphosate, glufosinate, all three herbicides in combination, or not treated with any of these herbicides. The results showed a low level of expression of the AAD-12, 2mEPSPS, and PAT proteins across herbicide treatments and environments, indicating a low exposure to humans and animals."

On July 13, 2012, the USDA published a notice in the Federal Register alerting the public that the petition was available for public review. The USDA would accept public comments submitted on or before September 11, 2012.

Related SourceWatch articles

 * Dow
 * Biotechnology
 * 2,4-D
 * Biotech Riders in the 2012 Farm Bill
 * Glufosinate
 * Roundup
 * Glyphosate
 * Glyphosate Resistant Weeds

External resources

 * Petition for Deregulation of Dow 2,4-D, Glyphosate and Glufosinate Tolerant, USDA.