EFS12- Book of abstracts - Contact

SESSION 2: SECONDARY METABOLITES – BIOCHEMISTRY,
BIOSYNTHESIS, FEED AND FOOD SAFETY
P39 - PCR chemotyping of Fusarium graminearum, F.
culmorum and F. cerealis isolated from winter wheat
in Wallonia, Belgium
P. Hellin, G. Dedeurwaerder, J. Ghysselinckx, A. Legrève
Université catholique de Louvain – Earth and Life Institute, Applied Microbiology, Phytopathology,
Croix du Sud 2, Box L7.05.03, B-1348 Louvain-la-Neuve, Belgium
E-mail: pierre.hellin@uclouvain.be
Within the pathogen complex responsible for Fusarium head blight (FHB) are
some species that can produce mycotoxins that accumulate in the grains, creating
a threat to human and animal health. In Europe, type B trichothecenes, especially
deoxynivalenol (DON), are frequently found in grain batches. Most of the genes
involved in producing these mycotoxins (TRI genes) are grouped in a 12-gene
core cluster (TRI cluster). Fusarium graminearum, F. culmorum and F. cerealis
possess this cluster, but the presence or absence of certain TRI genes, as well as
their functionality, results in a strain capable of producing either nivalenol (NIV) or
deoxynivalenol and a related acetylated derivative (3- or 15-ADON). Because of
the different levels of toxicity in these secondary metabolites, it is important to
have a better knowledge of the population in Belgium in order to estimate the risk
posed by Fusarium species occurring in wheat ears. Two multiplex PCR
reactions, targeting the TRI3 and TRI13 genes, were used to differentiate the
strains of the three species cited above in terms of the possible chemotypes (NIV,
3-ADON and 15-ADON). In all, 105 single-spore strains of F. graminearum, 90 of
F. culmorum and 20 of F. cerealis, isolated from winter wheat, were tested. The
three chemotypes were identified in the F. graminearum population, with the vast
majority of the strains (93%) being of the 15-ADON chemotype. For F. culmorum,
the 3-ADON chemotype was prominent (76.6%) and the rest of the strains were of
the NIV chemotype. The 20 tested F. cerealis strains could produce only
nivalenol. The different proportions of chemotypes in F. graminearum and F.
culmorum and the existence mixed-chemotype populations in the field indicate
different specificities of the chemotypes in epidemics.
Keywords: Fusarium head blight, mycotoxin trichothecene, genotype
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