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SESSION 3: PATHOGENESIS – EPIDEMIOLOGY AND POPULATION
GENETICS
Genetic and phenotypic diversity of Fusarium
graminearum, and interactions between Fusarium
species in oats
H. U. Aamot 1 , I. S. Hofgaard 1 , G. Brodal 1 , T. Ward 2 , A. Elameen 1 , T. Vrålstad 3 ,
G. Larsen 1,4 , P. E. Clasen 3 , O. Elen 1 , S. Klemsdal 1
1 Bioforsk, Norwegian Institute for Agricultural and Environmental Research, Plant Health and Plant
Protection Division, Høgskoleveien 7, 1432 Ås, Norway; 2 Microbial Genomics and Bioprocessing
Research Unit, National Center for Agricultural Utilization Research, US Department of Agriculture,
Agricultural Research Service, Peoria, IL 61604, USA; 3 Norwegian Veterinary Institute, Pb 750
Sentrum, N-0106 Oslo, Norway. 4 NorwegianUniversity of Life Sciences, 1432 Ås, Norway
E-mail: heidi.udnes.aamot@bioforsk.no
In Norway, Fusarium avenaceum, F. graminearum, F. culmorum, F. langsethiae,
and F. poae are some of the most common fungal species causing Fusarium
Head Blight in cereals. F. graminearum has shown increased prevalence the last
decade, resulting in increased deoxynivalenol contamination of cereal grains. The
increased prevalence of F. graminearum in Norwegian cereals is likely to be
associated with the recent increased use of reduced tillage in combination with
weather conditions promoting development and dispersal of this fungal species.
Association to changes in fungal traits is also possible. In a study of Norwegian F.
graminearum, isolates were collected in two time periods: Before 1998 (“old
isolates”) and after 2004 (“new isolates”). All isolates belonged to lineage 7.
Three-acetyl-deoxynivalenol (3-ADON) was the dominating genotype; however
15-ADON genotypes were identified among recently collected isolates. The
presence of two populations of F. graminearum was indicated: One containing the
majority of old isolates, the other population containing a majority of new isolates
(including the 15-ADON genotypes). No differences in aggressiveness on wheat
were observed between the two populations. In a greenhouse study of
interactions between Fusarium species in oats, F. graminearum appeared as one
of the most competitive species. Although not explained by our data, we cannot
exclude the possibility that the increased prevalence of F. graminearum in
Norwegian cereals could be associated with traits important for fungal fitness.
Keywords: fungal interaction, deoxynivalenol, 3-ADON, 15-ADON
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