Submitted to: Phytopathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/1/2005
Publication Date: 9/11/2005
Citation: Goswami, R., Kistler, H.C. 2005. Pathogenicity and in planta mycotoxin accumulation among members of the Fusarium graminearum species complex on wheat and rice. Phytopathology. 95:1397-1404.
Interpretive Summary: Fusarium head blight is a major threat to the profitable and dependable production of wheat and barley crops in the United States. By understanding the fundamental mechanisms by which these microorganisms cause disease, we may be able to develop novel, stable, and environmentally sensible disease management practices aimed at interfering with the essential processes of pathogenesis. This paper describes naturally occurring variability in the fungus with respect to its ability to cause disease that may be exploited for disease control. Once the environmental conditions required for epidemics and genetic potential of the fungus to cause disease are fully understood, management strategies could be tailored using these newly discovered requirements. The primary users of the research in this publication will be other scientists engaged in research to improve disease management on small grain crops.
Technical Abstract: Fusarium head blight (FHB), or scab, is a destructive disease of small grains caused by members of the Fusarium graminearum (Fg) species complex, comprised of at least nine distinct, cryptic species. Members of this complex are known to produce mycotoxins including the trichothecenes deoxynivalenol (DON) along with its acetylated derivatives and nivalenol (NIV). In this study, 31 strains, belonging to 8 species of this complex and originating from diverse hosts or substrates were tested for differences in aggressiveness and mycotoxin production. Large variation was found among strains, both in terms of their aggressiveness and the ability to produce trichothecenes on a susceptible cultivar of wheat; variation appears to be a strain-specific rather than species-specific characteristic. While pathogenicity was not influenced by the type of mycotoxin produced, a significant correlation was observed between the amount of the dominant trichothecene (DON and its acetylated forms or NIV) produced by each strain and its level of aggressiveness on wheat. Some isolates also were tested for their ability to infect a rice cultivar M201, commonly grown in the United States. While tested strains were capable of infecting rice under greenhouse conditions and causing significant amount of disease, no trichothecenes could be detected from the infected rice florets.