Kansas State University researchers have discovered how weeds develop resistance to the popular herbicide glyphosate, a finding that could have broad future implications in agriculture and many other industries, according to an article on the Kansas State Research and Extension website.
Their work is detailed in an article that appears in the March 12 edition of the Proceedings of the National Academy of Sciences.
“Herbicide resistance in weeds has been a huge problem, not only in Kansas and the U.S. but many parts of the world,” said Mithila Jugulam, a K-State weed scientist and co-author of the PNAS article.
“What we found that was new was how these weeds have evolved resistance to glyphosate in such a short time. If you look at the evolution of glyphosate resistance in Palmer amaranth, based on our research, it appears to have occurred very rapidly.”
“We found that glyphosate-resistant Palmer amaranth plants carry the glyphosate target gene in hundreds of copies,” Jugulam said. “Therefore, even if you applied an amount much higher than the recommended dose of glyphosate, the plants would not be killed.”
Bikram Gill, director of Kansas State University’s Wheat Genetics Resource Center who has worked in plant genetics for nearly 50 years, said the researchers knew pretty quickly that the genetic makeup of resistant weeds was different.
“Normally, the genetic material in all organisms – including humans – is found in long, linear DNA molecules, called chromosomes,” said Gill, another co-author of the study. “But when (K-State researchers) Dal-Hoe Koo and Bernd Friebe, the chromosome experts on the team, looked at these glyphosate-resistant weeds, the glyphosate target gene, along with other genes actually escaped from the chromosomes and formed a separate, self-replicating circular DNA structure.”