Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/16/2011
Publication Date: 9/1/2012
Citation: Foroud, N.A., McCormick, S.P., MacMillan, T., Badea, A., Kendra, D.F., Ellis, B.E., Eudes, F. 2012. Greenhouse studies reveal increased aggressiveness of emergent Canadian Fusarium graminearum chemotypes in wheat. Plant Disease. 96(9):1271-1279. Interpretive Summary: Fusarium Head Blight is caused by species of the fungus Fusarium which produce trichothecene mycotoxins. Ingestion of trichothecene-containing grain can result in a variety of symptoms including diarrhea, hemorrhaging and feed refusal. Previous studies have shown that the trichothecenes are also factors in the severity of the plant disease. In this study we found that the type of trichothecene produced by the fungus may also be a factor in the severity of the disease. Although North American Fusarium usually produces the trichothecene 15-ADON, strains that produce a related toxin, 3-ADON, have been increasingly found in North America. Wheat cultivars with moderate disease resistance had both more disease and higher toxin levels in the grain after infection with strains that produce the mycotoxin 3-ADON. Wheat growers can use this information to plant more highly resistant cultivars in regions where 3-ADON-producing Fusarium has been found.
Technical Abstract: The role of Fusarium graminearum trichothecene-chemotypes in disease outcomes was evaluated in a series of wheat lines with different levels of resistance to Fusarium Head Blight (FHB). Four inocula, each consisting of a composite of four strains with either 15-acetyldeoxynivalenol (ADON) chemotypes from ‘traditional’ or emergent populations, a 3-ADON chemotype, or a nivalenol (NIV) chemotype, were compared. The evaluated wheat included Canadian lines with different levels of FHB resistance/susceptibility, and double haploid lines developed from crosses of these lines. Highly resistant lines were resistant to infection by all of the F. graminearum chemotypes evaluated. In the moderately-susceptible/resistant wheat lines, the 3-ADON producers and the emergent 15-ADON population were generally more aggressive and resulted in higher Fusarium Damaged Kernel scores and levels of trichothecene accumulation. The data presented in this study demonstrate the importance of growing highly resistant wheat cultivars in the current climate of an evolving F. graminearum population, and suggest that moderate levels of FHB resistance may not be sufficient to minimize trichothecene contamination of grain from F. graminearum-infected wheat.