Emily Mackie, Andrew Barrow and Tatiana Soares da Costa. Credit: University of Adelaide
Key points:
- Future weed killers might be based on failed antibiotics, such as one originally created to treat tuberculosis.
- The altered antibiotic proved effective at killing two problematic weeds in Australia.
- The team is now looking at discovering more herbicidal molecules by re-purposing other failed antibiotics.
A molecule that was developed to treat tuberculosis but failed to progress out of the lab as an antibiotic is now showing promise as a powerful foe for weeds that cost farmers billions of dollars each year.
The failed antibiotic wasn’t a good fit for its original purpose, but scientists at the University of Adelaide discovered that once they altered its structure, it proved effective at killing two of the most problematic weeds in Australia—annual wild radish and ryegrass—without harming bacterial and human cells.
“Using failed antibiotics as herbicides provides a shortcut for faster development of new, more effective weed killers that target damaging and invasive weeds that farmers find hard to control,” said lead researcher Tatiana Soares da Costa from the University of Adelaide’s Waite Research Institute.
In a paper published in Communications Biology, researchers at the University’s Herbicide and Antibiotic Innovation Lab discovered there were molecular similarities between bacterial superbugs and weeds. They exploited these similarities and, by chemically modifying the structure of the failed antibiotic, were able to block the production of amino acid lysine, which is essential for weed growth.
“It’s also important to note that using failed antibiotics won’t drive antibiotic resistance because the herbicidal molecules we discovered don’t kill bacteria. They specifically target weeds, with no effects on human cells,” said Soares da Costa.
Researchers say besides aiding farmers, it could also lead to the development of new weed killers to target pesky weeds growing in our backyards. The team is now looking at discovering more herbicidal molecules by re-purposing other failed antibiotics.