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SESSION 5: DISEASE CONTROL AND FORECASTING MODELS
Maize kernel antioxidants and their potential
involvement in Gibberella and Fusarium Ear Rot
resistance
V. Atanasova-Penichon 1 , A. Picot 1 , L. Pinson-Gadais 1 , N. Ponts 1 , S. Pons 1 ,
G. Marchegay 1 , F. Turtaut 1 , M-N. Verdal-Bonnin 1 , C. Barreau 1,2 , J. Roucolle 3 ,
P. Carolo 4 , F. Richard-Forget 1
1 INRA UR1264 MycSA, 71 Avenue Edouard Bourlaux, CS20032, 33882 Villenave d'Ornon cedex-
France; 2 CNRS, INRA UR1264 MycSA, 71 Avenue Edouard Bourlaux, CS20032, 33882 Villenave
d'Ornon cedex-France; 3 Monsanto SAS Peyrehorade, Croix de Pardies, F-40300 Peyrehorade,
France; 4 Euralis Semences, 117 avenue de Vendôme, F-41000 Blois, FRANCE
E-mail: vessela.atanasova-penichon@bordeaux.inra.fr
Gibberella and Fusarium Ear Rot (mainly caused by Fusarium graminearum and
Fusarium verticillioides, respectively) are the two main diseases affecting
European maize crops. The two former fungi pose a serious threat to food safety
because of their ability to produce a wide range of mycotoxins, including type B
trichothecenes (produced by F. graminearum) and fumonisins (synthesized by F.
verticillioides). Since 2007, type B trichothecenes and fumonisins are strictly
regulated for the cereals commercialized in Europe. The maize variety is one of
the key factors that can significantly influence fungal development and mycotoxin
production on kernels. Plants can reduce mycotoxin accumulation by two
mechanisms: metabolic transformation of the toxin and inhibition of toxin
biosynthesis. This second mechanism involves the occurrence of biochemical
compounds that are able to modulate the biosynthesis pathways. Our previous
data showed that maize antioxidant secondary metabolites such as phenolic
compounds, tocopherols and carotenoids are present in the earliest maize kernel
stages, indicating that the mycotoxin-producing fungal species are likely to face
them during ear colonization and initiation of mycotoxin biosynthesis.
The potential involvement of maize antioxidants in plant resistance to Gibberella
and Fusarium Ear Rot and mycotoxin accumulation was the focus of this work.
The effect of phenolic compounds, tocopherol, and carotenoids on fungal growth
and type B trichothecene and fumonisin accumulation was investigated in vitro.
The highest inhibitory activities were obtained for -tocopherol and some of the
phenolic compounds including ferulic acid and its dimeric forms, caffeic and
chlorogenic acid. Using a set of genotypes with moderate to high susceptibility to
Gibberella and Fusarium Ear Rot, we assayed the significantly lowest levels of
chlorogenic acid, ferulic acid and its dimeric forms in immature kernels of the very
susceptible group. Overall, our data support the fact that these compounds may
contribute to resistance to Gibberella and Fusarium Ear Rot and/or mycotoxin
accumulation in various maize genotypes.
Keywords: Fusarium, mycotoxins, antioxidants, maize
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