Submitted to: Fungal Genetics Conference/Asilomar
Publication Type: Abstract Only
Publication Acceptance Date: March 20, 2005
Publication Date: March 20, 2005
Citation: Gale, L.R., Bryant, J.D., Ochocki, G.E., Ward, T.J., Kistler, H.C. 2005. Fusarium graminearum in the U.S.: Heterogeneous and in flux [abstract]. Fungal Genetics Newsletter 52 (Suppl):63. Technical Abstract: From a previous survey of diversity in Fusarium graminearum collected from 86 fields in 53 counties in 9 Midwestern states in 1999 and 2000, we identified a small population in North Dakota and Minnesota (7%) that produced 3-acetyl, deoxynivalenol (3ADON) that were genetically distinct (Nm = 0.5) from the predominant 15-acetyl, deoxynivalenol (15ADON) producing F. graminearum. Collections in 2003 from 40 wheat fields in 24 counties in North Dakota, and 9 fields in 7 counties in Minnesota resulted in 2,133 isolates. The 3ADON type was widespread and at high frequency (21% in ND, 24% in MN). Further analysis with primers targeting three VNTR loci demonstrated that recombination in F. graminearum, although occurring, may be an infrequent event, as only 70 potential recombinants between the two populations were identified. Chemotyping in collections from 2001-2003 indicates that 15ADON is still the only type in other Midwestern states, though the nivalenol type was the most frequent in isolates from Louisiana. The predominance of the nivalenol type in Louisiana and the build-up of the 3ADON type in Minnesota and North Dakota suggest that selection is a principle evolutionary force acting on populations of F. graminearum. At the same time this study demonstrates the need for continual monitoring of the population composition, as F. graminearum in the U.S. is certainly not as homogeneous as previously believed.