Rice Blast and Wheat Blast Impact Major World Crops
OARDC researchers have generated information critical to the development of disease-resistant varieties for rice and other crop plants, with a focus on rice blast, a devastating rice disease, with implications for wheat blast, an emerging disease in South America and the U.S.
Most plant diseases are caused by fungal pathogens and pose continual threats to sustainable crop production worldwide. OARDC research centers on understanding the host plant responses to rice blast, caused by the fungal pathogen Magnaporthe oryzae. Rice blast is a devastating disease and estimated to cost an estimated $66 billion in annual losses worldwide.
In an alarming development, wheat blast, caused by a related fungus, Magnaporthe grisea, has emerged in South America and recently detected in Kentucky. Rice blast and wheat blast pose great threats to global crop production and food security.
Disease-resistant cultivars are the most effective, economical, and environmentally sound means to manage rice blast, but no cultivar is resistant to all races of the rice blast fungus, and there are no wheat cultivars resistant to wheat blast. OARDC researchers are using tools of molecular genetics and genomics to generate key information for the development of resistant varieties for rice and other crop plant, centered on understanding how a fungal pathogen manipulates the host plant's defense and cause disease.
Specifically, Guo-Liang Wang and researchers have determined that the AvrPiz-t effector from the fungal pathogen Magnaporthe oryzae has both avirulence and virulence functions and suppresses the host ubiquitin proteosome system during infection. In addition, the Mitchell and Wang laboratories found that the AvrPiz-t gene is present in the two sequenced wheat blast strains from South America, suggesting the resistance gene Piz-t might be effective against wheat blast.
Rice is a model plant for cereal crops and the rice blast system is an advanced model for study of plant-fungal interactions. Our research demonstrates that modifications of the ubiquitination-related host targets may provide a novel approach to effectively control fungal diseases. The information generated from this project will also have direct and indirect applications in controlling important fungal diseases in other cereals crops such as wheat and corn grown in Ohio. Our expertise in the molecular genetics, genomics, bioinformatics of rice resistance and M. oryzae pathogenesis coupled with our expertise and capabilities in disease control and Extension, position us to lead national efforts to address these critical challenges in food production.
Guo-Liang Wang, Thomas K. Mitchell, Pierce A. Paul