1a. Objectives (from AD-416)
The overall goal of this project is to contribute to the effective control of toxigenic Fusarium, especially those responsible for FHB of small grain cereals, in order to enhance food safety and crop production in the U.S. and around the world. The proposed project is designed to produce a robust evolutionary framework for understanding the genetic and phenotypic diversity, geographic distribution and population biology of toxigenic fusaria, and will result in novel technologies for the rapid detection, identification and control of toxigenic fusarial pathogens of critical importance to food safety and food security. This framework will also support and facilitate work by the global Fusarium research community. The specific objectives are: Objective 1: characterize the genetic diversity and mycotoxin potential of Fusarium head blight and other fusarial pathogens, develop novel pathogen detection technologies, and expand web-accessible informational database to facilitate the rapid and accurate identification of toxigenic fusaria via the Internet. Objective 2: Determine the global population structure of F. graminearum and identify genetic variation associated with population-level difference in growth, reproduction, and toxin accumulation phenotypes as a means to improve pathogen modeling and surveillance. Objective 3: Characterize the mechanisms that drive the diversification and adaptive evolution of virulence genes in Fusarium genomes as well as host defense genes involved in immunogenicity and disease response.
1b. Approach (from AD-416)
Toxins produced by plant-pathogenic Fusarium pose a significant threat to food safety and place a major burden on the world’s agricultural economy. The primary objectives of the proposed research are to: 1) Characterize the genetic diversity and mycotoxin potential of Fusarium head blight (FHB) and other fusarial pathogens, develop novel pathogen detection technologies, and expand web-accessible informational databases to facilitate the rapid and accurate identification of toxigenic fusaria via the Internet; 2) Determine the global population structure of F. graminearum and identify genetic variation associated with population-level differences in growth, reproduction, and toxin accumulation phenotypes as a means to improve pathogen modeling and surveillance; and 3) Characterize the mechanisms that drive the diversification and adaptive evolution of virulence genes in Fusarium genomes as well as host defense genes involved in immunogenicity and disease response. These complementary objectives are directed at developing robust pathogen control strategies through elucidating the evolution, population structure, phenotypic diversity, host range, geographic distribution, and adaptive potential of toxigenic fusaria. In addition, the planned research will produce enhanced methods for identification and characterization (e.g. toxin type, toxin accumulation potential, and host preference) of Fusarium responsible for mycotoxin contamination of cereals and other food. The information and molecular tools developed as a result of this project will address the needs of small grain cereal producers, food and feed processors, the United States Department of Agriculture (USDA), Federal Grain Inspection Service (FGIS), the USDA Animal and Plant Health Inspection Service (APHIS), and the Food and Drug Administration (FDA).
3. Progress Report
This research is directed at developing robust Fusarium head blight cereal pathogen control strategies and enhanced methods for identification and characterization of species responsible for mycotoxin contamination of cereals and other food. The following two complementary approaches were employed. First, Fusarium pathogens were characterized genetically to develop novel pathogen detection technologies and to expand web-accessible informational databases to facilitate the rapid and accurate identification of toxin-producing pathogens via the Internet. Secondly, global population genetic studies were conducted to improve Fusarium head blight pathogen surveillance.
1. Some Fusarium pathogens prefer wheat, others prefer corn. Understanding the spectrum of pathogens that cause Fusarium head blight of wheat and barley and ear rot of corn, and the toxins they produce, are essential for developing robust disease control strategies and cultivars with broad based resistance to these economically devastating diseases. To assess possible host preferences and toxin potential, Agricultural Research Service (ARS) scientists from the Bacterial Foodborne Pathogens and Mycology Research Unit in Peoria, IL, DNA typed 560 Fusarium isolates from wheat, barley and maize. Although F. graminearum was the dominant head blight pathogen of wheat and barley, ear rot of corn was caused exclusively by F. boothii, suggesting that the latter species is better adapted to infect corn. Because the exotic pathogen F. boothii was recently detected within the U.S., annual surveys are needed to monitor whether this new pathogen is spreading into major production areas and to guide selection of corn cultivars with the greatest resistance to this pathogen.
Boutigney, A., Ward, T.J., Van Coller, G.J., Flett, B., Lamprecht, S.C., O Donnell, K., Viljoen, A. 2011. Analysis of the Fusarium graminearum species complex from wheat, barley, and maize in South Africa provides evidence of species-specific differences in host preference. Fungal Genetics and Biology. 48(9):914-920.