Northern Corn Leaf Blight Genes Now Identified

Northern corn leaf blight causes major yield losses if not detected and treated early. Resistance genes have been identified in corn, but the fungal disease has found ways to sneak around the plant's defenses. Now, researchers have figured out how the fungus is outsmarting corn, and this information may help corn fight back.

A new study from the University of Illinois led by plant pathologist Santiago Mideros has identified two of the genes that cause disease in corn. Several genes help corn resist different strains of northern corn leaf blight: Ht1, Ht2, Ht3, and HtN. These genes may signal proteins that protect the plant from fungus attacks, but the exact mechanism is unknown. The corn becomes susceptible again when the fungus evolves to avoid detection by the plant.

The interaction between corn and fungal genes has been known for decades, but scientists didn't know the molecular makeup of those genes in the fungus, or their location in the genome. To get this information, the research team mated different strains of the fungus and mapped the genes of the resulting progeny. They then confirmed the location for one fungal gene involved in the disease, AVRHt1, and found a candidate location for another, AVRHt2. The researchers also identified molecular markers that should make identifying disease-causing strains easier in the future.

For more information, read the news release at the ACES College News.