University of Georgia professor Richard Hussey, a distinguished research professor in plant pathology at the UGA College of Agricultural and Environmental Sciences, has spent 20 years studying a worm-shaped parasite too small to see without a microscope. His discovery is vastly bigger. Hussey and his research team have found a way to halt the damage caused by one of the world's most destructive groups of plant pathogens through bioengineering.

Root-knot nematodes are the most economically important group of plant-parasitic nematodes worldwide. With about 2,000 species, they attack nearly every food and fiber crop grown. The nematodes also invade plant roots and, by feeding on its cells, they cause the roots to grow large galls—or knots—that damage the crop and reducing its yields.

Working with assistant research scientist Guozhong Huang and research technician Rex Allen, with a collaboration of Eric Davis at North Carolina State University and Those Baum at Iowa State University, Hussey discovered how to make plants resistant to root-knot nematode infection.

Hussey's group bioengineered plants that prevent the nematode from feeding on the roots, the results of which were published last September 26 in the journal “Proceedings of the National Academy of Sciences.”

Four common root-knot nematode species account for 95 percent of all infestations in agricultural land. By discovering a root-knot nematode parasitism gene that is essential for the to infect crops, the scientists have developed a resistance gene that is effective against all four species.

Using a technique called RNA interference, the researchers have effectively turned the nematode's biology against itself. They genetically modified Arabidopsis, a model plant, to produce double-stranded RNA to knock out the specific parasitism gene in the nematode when it feeds on the plant roots. This knocked out the parasitism gene in the nematode and disrupted its ability to infect plants.

Funding for the project came from the US Department of Agriculture's Cooperative State Research, Education, and Extension Service National Research Initiative, and the UGA College of Agricultural and Environmental Sciences.