Pioneer Hi-Bred International Inc. has plans to introduce hybrids and varieties with an alternative trait for resistance to both glyphosate and sulfonylurea herbicides towards the end of this decade. Scientists at Verdia, a firm which Pioneer’s parent company, DuPont, bought in 2004 and integrated into Pioneer’s crop genetics research and development division, developed an enzyme exhibiting glyphosate N-acetyltransferase (GAT). This enzyme renders glyphosate ineffective in a different way than current glyphostate-resistance technologies.

Glyphosate operates by inhibiting the enzyme enolpyruvyl-shikimate-3-phosphate synthase (EPSPS) that leads to the biosynthesis of essential aromatic amino acids. The inhibition does not allow plants to survive. Researchers have found some microbial EPSPS enzyme variants that are not inhibited by glyphosate. Plants that contain these enzyme variants can even survive in the presence of high concentrations of the herbicide.