Novel Form of 2-4 D Resistance in Broad Leaf Crops using Gene Editing

Background

2,4-D is an herbicide is used to selectively kills most broadleaf weeds in grasses (crops, turf, pasture, range).  It is one of the oldest and most widely available herbicides and defoliants in the world, having been commercially available since 1945.

In 2010, Dow published that it had created genetically modified soybeans made resistant to 2,4-D by insertion of a bacterial aryloxyalkanoate dioxygenase gene, aad1.  Dow intended it to be used as an alternative or complement to Roundup Ready crops due to the increasing prevalence of glyphosate-resistant weeds.  As of April 2014, genetically modified maize and soybeans resistant to 2,4-D and glyphosate have been approved in Canada. In September 2014, the USDA also approved Dow’s maize and soybeans, and in October, the EPA registered the “Enlist Duo” herbicide containing 2,4-D and glyphosate.

These current 2,4-D resistant crops (among others) use a transgene from bacteria and are subject to GMO regulations.

Advantages

• Can generate resistance in broad-leaf crops (e.g., sunflower, tomato, soybean, cotton, canola, flax)
• Use of gene editing is not considered a transgenic approach in the US (among other countries) and thus not subject to GMO regulations

Last updated: December 2019