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News Release

January 04, 2007

Research by U of G Prof Makes 'Top Science Stories' List

Research by a University of Guelph professor on how an invasive weed is engaging in underground chemical warfare by poisoning the allies of native trees has been named one of the top science stories of 2006 by Discover magazine.

Guelph ecologist John Klironomos made headlines last May when he published a study that found that the weed garlic mustard (Alliaria petiolata), which grows abundantly in Canada and the United States, releases chemicals under the soil that are detrimental to the fungi that native trees depend on for growth and survival.

It was the first study to show that invasive plants are hurting indigenous species by thwarting the ecological relationship between roots and certain fungi.

Now Discover magazine has included Klironomos’ research in its Top 100 Science Stories of 2006 issue released this week. According to the magazine, the issue contains the most important and interesting science stories of the year. Klironomos’ study, which was conducted with Kristina Stinson of Harvard University and a team of other researchers from Guelph, the United States and Germany, was named one of the “Top Six Environment Stories.”

“It is great that our research was picked up by Discover,” said Klironomos, who is currently conducting research in France. “It’s an excellent opportunity to tell our story to the general public.”

Garlic mustard targets and poisons arbuscular mycorrhizal fungi, the main fungal allies of native trees like maple, ash and other hardwoods. The fungi have long microscopic threads that create a subterranean network, allowing for the exchange of nutrients with indigenous trees. The fungi rely on the trees for energy, and the trees rely on the fungi for nutrients.

“This noxious weed is disrupting an intimate symbiosis between native species and fungi that has been going on for millions of years,” Klironomos said. “This is affecting current and future generations of trees and changing the habitat.”

Once garlic mustard produces these compounds and has invaded an area, even removing the weed doesn't help much. "The compound is still in the soil and it's hard to plant any native plants in the area and have them establish properly,” he said.

The research was originally published in the May issue of the Public Library of Science.