Living in the soil, roundworms can infect plants via their roots, which is why many plants have evolved to produce an immune response when the worms are detected. Now, scientists have harnessed that response to create an eco-friendly form of crop protection.

Led by Senior Research Associate Murli Manohar, along with professors Daniel Klessig and Frank Schroeder, a team from New York state's Boyce Thompson Institute started by isolating a roundworm metabolite known as ascr#18. That compound is a type of ascaroside pheromone, and is used by many species of worms to chemically communicate. When plants detect it, they "know" that roundworms are nearby.

The researchers proceeded to apply small amounts of ascr#18 to four crop plants: soybeans, rice, wheat and maize. They then infected those same plants with a virus, bacteria, fungus or oocmycete (water mold). When compared to a control group of untreated plants several days later, the treated ones had fared much better, as their immune-response boost made them significantly more resistant to the pathogens.

It was found that the amount of ascr#18 needed for optimal results varied between plant species. This was likely due to the fact that different plants express different amounts of ascaroside-detecting receptor proteins, plus the specific proteins that are expressed may vary in sensitivity.

In previous studies, Klessig and Schroeder showed that ascr#18 and other roundworm-produced pheromones also helped to protect plants such as tomato, potato, barley and Arabidopsis (a member of the mustard family). Significantly, because such compounds don't actually kill the pathogens – or anything else – their application should be a much more environmentally-friendly way to go than the traditional use of toxic pesticides.

Also taking part in the research were scientists from Cornell University, the University of Kentucky, Justus Liebig University in Germany, the University of California-Davis, and Colorado State University. The technology is now being commercialized by spinoff company Ascribe Bioscience, under the trade name Phytalix.

A paper on the study was recently published in the Journal of Phytopathology.