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Research Highlights

Research Highlights
Researchers are Working to Improve Herbicide Resistance in Soybeans

Photo: United Soybean Board

By Julie Meyer

In the face of the challenges posed by herbicide-resistant weeds in North Central United States soybean fields, molecular biologist Feng Qu, at the Ohio Agricultural Research and Development Center, has a novel solution. 

With checkoff support from the North Central Soybean Research Program and the United Soybean Board, Qu is collaborating with a team of researchers from three states using molecular techniques to equip soybean with tolerance to herbicides not currently used on soybean.  

“We are using CRISPR-Cas technology to engineer herbicide resistance, herbicide tolerance in soybeans,” says Qu. “We already have soybeans genetically tolerant to Roundup and because of the long-time use, weeds have become resistant to Roundup. We are trying to engineer the normal herbicide tolerance trait in soybeans so we can use other types of herbicides that are not currently widely used.”

CRISPR is the acronym for Clustered Regularly Interspaced Short Palindromic Repeats, which works together with Cas (CRISPR-associated protein) as “molecular scissors” that cut one or both strands of DNA at certain locations to allow for improvements in plants and animals.

Specifically, Qu and his research team are using CRISPR technology to modify three soybean genes: ALS, PDS, and HPPD. This would enable soybean to tolerate the corresponding herbicides: Imazapyr, fluridone, and mesotrione. These classes of herbicides are considered relatively safe but are not currently used on soybean because the crop’s intolerance.

“For example, there is a type of herbicide that I use in aquculture used to kill weeds in water,” Qu says. “This herbicide has been rigorously tested and proven to be quite safe. But soybeans are not tolerant to this herbicide.”

This herbicide corresponds with the soybean PDS gene. To gain tolerance to herbicide, the PDS gene needs to lose susceptibility to the herbicide, which is where CRISPR is used. Qu says that he wants to give soybeans the tools to fight and withstand these herbicides to stay alive.

Unlike older herbicide tolerance traits, such as Round-up and Dicamba tolerance, the new traits are being developed using CRISPR technology, which is considered a natural process and doesn’t directly introduce non-plant genes. 

“The most widespread use of CRISPR technology has focused on removing, or knocking out, unwanted traits or genes that we don’t want. That is not what we are interested in,” says Qu. “We are using CRISPR to improve plant genes, and one of the improvements is to increase the herbicide tolerance trait.”

The process is challenging as the team does not want to lose the current herbicide tolerance in the process, but have the outcome include both current and new tolerances. 

Qu and his team see the outcomes of this project as soybean seed stock equipped with three new herbicide tolerance traits. The traits could be individual or combined in the same seed.  Soybean growers will then have the ability to use three novel classes of herbicides with diverse modes of action. Furthermore, two or more herbicides could be combined to delay the emergence of resistant weeds, providing durable weed control. 

The collaborators in this study include Bing Stacey, University of Missouri; Tom Clemente, University of Nebraska; and Bob Stupar, University of Minnesota.

To find research related to this Research Highlight, please visit the National Soybean Checkoff Research Database.