University of Toronto professor finds key protein in fight against plant disease

A University of Toronto botanist has identified a protein that ultimately could provide chemical-free ways to protect crops from disease.

“Finding this protein, called DIR1, could help make it possible to genetically engineer crops that resist disease-causing organisms,” says Robin Cameron, a professor of botany at U of T and the senior investigator of the study, which appears in the Sept. 26 issue of Nature. “In the long run, having a better understanding of the whole process of disease resistance in plants could eliminate the need for fungicides or bacteriocides.”

When disease strikes a plant, its immune system sends up a warning “flare” telling different areas of the plant to resist infection. “This process is kind of like vaccination, only better,” Cameron says. Once the signal-dependant on DIR1-is triggered by one disease, it gives the plant systemic acquired resistance (SAR) to many other diseases. The exact role of DIR1 in the signal process is not yet clear, she says.

Cameron, along with colleagues at the Salk Institute in La Jolla, Calif., the John Innes Centre in Norwich, U.K. and the Noble Foundation in Ardmore, Okla., studied a mutant strain of weed with abnormal DIR1 that does not develop SAR when exposed to a certain bacterial disease. “Our studies indicate that the normal protein, DIR1, is required to either make or move the warning signal around the plant,” she says.