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SESSION 6: FUTURE CHALLENGE FOR EUROPE AND WORLDWIDE
P139 - Relationship between cadmium and type B
trichothecenes contamination in wheat kernels
S. Claude 1 , V. Atanasova-Penichon 1 , L. Pinson-Gadais 1 , C. Ducos 1 , M-N.
Verdal-Bonnin 1 , L. Denaix 2 , J. Y. Cornu 2 , F. Richard-Forget 1
1 INRA, UR1264 MycSA, 71 Avenue Edouard Bourleaux, CS20032, 33882 Villenave d'Ornon cedex-
France; 2 INRA, UMR 1220 TCEM, 71 Avenue Edouard Bourleaux, CS20032, 33882 Villenave d'Ornon
cedex-France
E-mail: fforget@bordeaux.inra.fr
Cadmium (Cd) and mycotoxins are among the most worrying contaminants that
may affect the safety of wheat kernels and derived products. Cadmium is a trace
element naturally occurring in the environment, entering agrosystems through
natural processes (geological materials) and anthropogenic activities such as
atmosphere deposition, sewage sludge disposal, fertilizer application. It is readily
taken up by wheat crops and transferred to edible parts where it can be
accumulated. The main mycotoxin hazards associated with wheat in Europe
results from the development of toxigenic Fusarium species (mainly Fusarium
graminearum) in the growing crop and the most frequently encountered mycotoxin
is deoxynivalenol or DON, belonging to the type B trichothecenes group. Cd and
DON contents in commercialized kernels for human consumption are strictly
regulated in Europe (EC N o 1881/2006 and EC N o 856/2005, respectively).
Although there is no complete understanding of how wheat responds to soil Cd,
increasing evidence indicates that the toxicity of Cd may be associated with
oxidative damage caused by reactive oxygen species. This Cd induced oxidative
stress together with the occurrence of Cd traces in kernels tissues are two factors
that can affect the infection and development of F. graminearum and its ability to
produce mycotoxins. Indeed reactive oxygen species and metals have been
reported to impact trichothecenes biosynthesis (Pinson-Gadais et al., 2008; Ponts
et al., 2007). To decipher this potential relationship, F. graminearum strains were
inoculated on kernels harvested from Cd-contaminated soils and in liquid media
supplemented with a gradient of Cd concentrations. Impact of Cd on fungal
growth and on DON biosynthesis was investigated together with the ability of Cd
to induce oxidative stress in the fungal cell and of F. graminearum to
bioaccumulate Cd. The resulting data that support the fact that DON
contamination of kernels can be significantly influenced by Cd soil contamination
will be discussed.
Keywords: Cadmium, type B trichothecenes, wheat
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