Researchers at Colorado State University have developed a new herbicide-resistance trait for dicot crops such as cotton, soybean, and tomato. The trait enables tolerance to widely used auxin herbicides, including dicamba and 2,4-D. The team also created a DNA marker to quickly identify resistant plants. These tools support faster and more precise breeding of herbicide-tolerant crops.
Auxin herbicides remain a key tool for controlling broadleaf weeds, including those resistant to other chemistries like glyphosate. However, many dicot crops are sensitive to these herbicides, which limits their use in production systems. A naturally occurring mutation first identified in Bassia scoparia revealed a new mechanism of resistance that does not rely on herbicide breakdown. Recent research shows this mutation alters auxin signaling at the receptor level, offering a novel and transferable trait. This approach could expand weed-control options while helping maintain crop yield and reduce resistance pressure.
The technology is based on a mutation in the AUX/IAA16 gene that changes how plants respond to auxin herbicides. An insertion disrupts normal RNA splicing, producing a modified protein that weakens interaction with the receptor complex. Because auxin herbicides rely on this interaction to trigger plant death, the reduced binding lowers herbicide sensitivity while preserving normal growth.
New findings further confirm that this mutation reduces degradation of AUX/IAA16 in the presence of auxins, stabilizing the protein and limiting downstream signaling. In Arabidopsis thaliana, engineered lines showed strong tolerance to dicamba and 2,4-D, with minimal impact on root growth under treatment. A linked molecular marker enables rapid screening, and the trait can be deployed through gene editing, transgenic approaches, or mutagenesis. The function of this mutation has also been demonstrated in tobacco and soybean, data available upon request.
Available for Exclusive Licensing
TRL: 3
Todd Gaines
Jacob Montgomery
Neeta Soni-Castillo
Eric Patterson
Eric Westra
Sarah Morran
Jessy McGowan
Jessy.McGowan@colostate.edu
970-491-7100