Delaware researchers strive to fight rice disease

The fungus Magnaporthe oryzae may soon cause fewer headaches for rice farmers if University of Delaware research continues to be successful. 

The research on the fungus, which causes the No. 1 rice killer, rice blast disease, was published in in December in Frontiers in Plant Science and in Current Opinion in Plant Biology.

"Rice is a food the world relies on -- it accounts for about one-fifth of all the calories humans consume," Harsh Bais, associate professor of plant and soil sciences at Delaware’s College of Agriculture and Natural Resources and the lead professor of the research, said. "So it's critical to find ways to reduce the impact of rice blast disease, especially as global population is expected to exceed 9 billion by 2050, and the need for more food increases."

The University of Delaware research team found that rice blast fungus invades a rice plant and causes an increase of abscisic acid, suppressing the plant’s defense mechanisms. This occurs when limited water is available for rice plants, causing a stress hormone to close off the evaporation of water from the plant and increasing the virulence of the fungus.

Abscisic acid causes rice blast fungus to expand, but it also helps save the plant during drought, which has made the study and production of a fungicide particularly difficult.

"The rice blast fungus uses abscisic acid to its own advantage, which is absolutely wild," Bais said. "People have been struggling to find targets for controlling rice blast, and now we have one, with abscisic acid. It's one of those classic holy grails because this fungus affects not only rice, but also barley and wheat."

In addition to the leadership of Bais, the first author of both research articles was graduate student Carla Spence. The co-authors included postdoctoral researcher Venkatachalam Laksmanan and Nicole Donofrio, associate professor of plant and soil sciences.