Corn Gene Fights Multiple Leaf Diseases

One little gene in corn can make the difference in susceptibility to three major leaf diseases, according to USDA researchers. Three diseases – southern corn leaf blight, northern leaf blight, and gray leaf spot – all cause lesions on corn leaves worldwide and the latter two are significant problems for Midwest corn growers.

The discovery, by a team of USDA Agricultural Research Service scientists and university colleagues, could potentially help plant breeders build disease-resistance traits into future corn plants.

The researchers examined 300 corn varieties from around the world to look for those with resistance to the three diseases in order to determine which genes underlie disease resistance. When they tested the lines for resistance, they found that if a corn variety was resistant to one disease, chances were favorable that it was also resistant to the other two.

The researchers applied a statistical analysis technique called “association mapping” to identify regions of the genome associated with variation in disease resistance. According to Balint-Kurti, the scientists knew there was a strong correlation between resistance of one disease and the other two. They postulated that some resistance genes conferred resistance to two or more different diseases, and they identified a gene that seemed to confer multiple disease resistance.

This gene, a GST (glutathione S-transferase), is part of a family of genes known for their roles in regulating oxidative stress and in detoxification. Both of these functions are consistent with a role in disease resistance.

Read more from USDA-ARS.