For generations, farmers have relied on the spraying of herbicides to prevent invasive plants and weeds from choking their soybean, corn and wheat crops. But over the last several years, this tried-and-true system has been faltering.

Weeds are quickly evolving resistance to even the most advanced herbicides, including glyphosate – better known as Roundup – which was first introduced to farmers in the 1970s by agrochemical giant Monsanto. Herbicide-resistant weeds have brought farmers to their knees, desperate for solutions for protecting their crops.

Todd Gaines, an associate professor in the Department of Agricultural Biology, is one of weeds’ worst enemies. His expertise is in the molecular and genetic underpinnings of the most highly evolved superweeds of the world, with the goal of helping farmers target these foes with new, genetically precise and sustainable methods.

Gaines is now leading a project aimed at changing the game of weed control by using an entirely new mode of action to combat the most out-of-control weed species, king among them, a noxious, highly herbicide-resistant weed called Palmer amaranth.

Biotech company partnership
Gaines is partnering with biotechnology company AUM LifeTech to research the application and methods of an emerging gene-silencing weed control technology. Their method uses molecular tools called antisense oligonucleotides, which are next-generation single-stranded nucleic acid molecules, to infiltrate the cells of weed plants and target single strands of RNA. The molecular targets would be so specific that the crops would remain untouched.

Their goal is to optimize a delivery system in the form of a nanoparticle-based, shelf-stable spray. If they’re successful, their technology would give farmers a non-genetically modified, environmentally conscious tool to control weeds that are rapidly gaining the upper hand against legacy herbicides.

“This is the most exciting thing I have ever worked on in terms of promise,” Gaines said. “If we can solve this problem, this will be something every single person out there managing weeds will be affected by.”

He added that among his larger goals is to help make farming systems more sustainable, both by helping farmers maintain their livelihoods, and by making products that are safe for the public and the environment. “We need to help ensure we are not harming other organisms, while also managing these weeds.”

DARPA funding
Gaines and collaborator Veenu Aishwarya, founder and Chief Executive Officer of AUM LifeTech, are funded by the Defense Advanced Research Projects Agency for their two-year project, in which they will prove out the fundamental technology and test a delivery system.

Their system will focus on Palmer amaranth as a test case, a hardy and aggressive pigweed that exhibits extensive herbicide resistance and is a growing problem for commodity farmers. Its genome has been sequenced thanks in part to an international weed genomics consortium that Gaines also leads.

Antisense oligonucleotide technology is better known in life science applications because of its promise as a targeted therapeutic device for a host of diseases, including neurological and autoimmune disorders. But Aishwarya has long seen the potential for these single-stranded DNA molecules to be useful in agricultural settings, and he wants to expand his company in that direction.

“Since our gene silencing products use a non-GMO and non-permanent approach, this makes this technology very attractive for such applications,” said Aishwarya in a press release announcing the partnership.

A chance encounter with Gaines at an agricultural biotechnology conference several years ago paved the way for the partnership; now, AUM LifeTech’s proprietary gene silencing technology will form the basis of the RNA-targeting system he and Gaines will develop and test together.

“Todd’s work in collaboration with AUM LifeTech in RNA targeting to develop next-generation herbicides is an exciting example of CSU’s leadership in life science breakthroughs for agricultural applications,” said Alan Rudolph, vice president for research and a former program manager at DARPA. “The awarding of DARPA funds to address the intractable problem of herbicide resistance speaks to the extraordinary work of Todd and his team in developing new, molecular strategies to combat the worst effects of invasive plant species on our food supply.”