Maize geneticist Surinder Chopra is working to transfer from sorghum to corn the natural ability to withstand the fungus anthracnose. A portion of the corn crop, especially in the Midwest corn belt, is lost to the disease each year.

The ultimate goal of McNellis’s research is to develop apple tree rootstocks that confer good resistance to fire blight. “But a more realistic goal is to develop gene activity markers that can be used to look at very young trees to see if that gene is active or not,” he says. “That would allow breeders to select trees for traits—give them a way of winnowing through a large number of trees to find the ones that will likely have the traits that they want.”

Gene expression also is at the heart of research on disease resistance in corn, Pennsylvania’s top field crop. Geneticist Surinder Chopra is working to transfer from sorghum to corn the natural ability to withstand the fungus anthracnose. A portion of the corn crop, especially in the Midwest corn belt, is lost to the disease each year.

Scientists know that the compounds that provide fungal resistance in sorghum are responsible for the maroon-colored pigments that characterize Indian corn and that turn sorghum colorful in the fall.

“When sorghum is challenged with anthracnose fungi, the plant responds to the stress by releasing a chemical compound to its leaves that acts as a fungicide,” Chopra explains. “Sorghum and corn are closely related plants, and we believe that corn has the same genes as sorghum that are responsible for the production and release of fungicides, called phytoalexins. But for reasons that we are trying to understand, those genes are not ‘turned on’ in corn. We are studying how to make those genes express themselves in corn and protect the plants from the fungus.”

From previous research, scientists know that modified versions of compounds that provide fungal resistance in sorghum are responsible for the maroon-colored pigments that characterize Indian corn and that turn sorghum colorful in the fall. “We have been studying gene expression of corn at the molecular level, trying to discover what genes control pigmentation,” Chopra says. “We believe the pigmentation pathway can become the basis for study of certain compounds that are induced in corn when plants are challenged or stressed by disease. Using anthracnose as a pathogen, and sorghum as a similar resistant plant, the goal is to transfer that anthracnose resistance into corn.”