Scientists at the University of Adelaide have engineered a failing tuberculosis antibiotic into a powerful herbicide capable of tackling two invasive weeds endemic in Australia without harming people or bacterial cells. The approach, which involves making structural modifications to molecules to stop weeds from growing, could revolutionize the development of herbicides and offer farmers and homeowners a faster and more economical solution to dealing with weed infestation plan.

Future herbicides may soon be based on failed antibiotics.

A molecule originally designed to fight tuberculosis, though not used as an antibiotic in the lab, is now showing potential as a formidable foe against the weeds that infest our gardens and cost farmers billions of dollars every year.

While the failed antibiotic was ill-suited for its original purpose, University of Adelaide scientists discovered that by tweaking its structure, the molecule could effectively kill two of Australia's most problematic weeds, annual ryegrass and wild radish, without harming bacteria and human cells.

"This discovery could be a game-changer for the agricultural industry.” Lead researcher Dr Tatiana Soares da Costa from the Waite Institute at the University of Adelaide said. “Many weeds are now resistant to existing herbicides on the market, and costing farmers billions of dollars each year. Using failed antibiotics as herbicides offers a shortcut to more rapid development of new, more effective herbicides that target destructive and invasive weeds that farmers struggle to control.”

Researchers at the university's Herbicide and Antibiotic Innovation Lab have discovered that superbugs and weeds share molecular similarities. They took advantage of these similarities, and by chemically modifying the structure of a failed antibiotic, they were able to block the production of lysine, which is required for weed growth.

"There are no commercial herbicides like this on the market. In fact, in the past 40 years, hardly any new herbicides with new mechanisms of action have entered the market," Dr Andrew Barrow said. He was a postdoctoral fellow in Tatiana Soares da Costa's group at the Waite Institute at the University of Adelaide.

Weeds are estimated to cost Australian agriculture more than $5 billion annually. Annual ryegrass in particular is one of the most serious and costly weeds in southern Australia.

"This short-cut strategy saves valuable time and resources, so it can speed up the commercialization of much-needed new herbicides," said Dr. Soares da Costa.

"It's also important to note that use of failed antibiotics does not lead to antibiotic resistance because the herbicide molecules we discovered do not kill bacteria. They specifically target weeds and have no effect on human cells," she said.

It's not just farmers who could benefit from this discovery. It could also lead to the development of new herbicides to combat the pesky weeds that grow in our backyards and driveways, the researchers say.

"Our repurposing method has the potential to uncover widely applied herbicides that can kill a wide variety of weeds," Dr Barrow said.

Dr. Tatiana Soares da Costa and her team are now looking for more herbicide molecules to bring new, safe herbicides to market by repurposing other failed antibiotics and collaborating with industry.

Collected by Lifeasible. As a biotechnology company, Lifeasible is specialized in agricultural science, offering a wide variety of agro-related services and products for environmental and energy solutions. The company now provides plant genetic engineering, plant transformation, plant tissue culture, analytical services, plant breeding, forest genetic improvement, plant organelles and sweet protein research.