Research article

Lower mycotoxin levels in Bt maize grain

¹ Université de Pau et des Pays de l’Adour, UMR CNRS 5254, IPREM - EEM - IBEAS, BP 1155, 64013 Pau, France
² Ministère de l’Agriculture et de la Pêche, Service Régional de la Protection des Végétaux, “Midi-Pyrénées", Bât. E, Bd Armand Duportal, 31074 Toulouse, France
³ Laboratoire de Développement et d’Analyse des Côtes D’Armor (L.D.A 22), 7 rue du Sabot, BP 54 Zoopole, 22440 Ploufragan, France
⁴ Université de Pau et des Pays de l’Adour, UMR 1224, ECOBIOP, IBEAS, BP 1155, 64013 Pau, France
⁵ Chambre d’Agriculture du Bas-Rhin, Filières végétales, 2 route de Rôme, BP 30022, Schiltigheim 67013 Strasbourg Cedex, France
⁶ Fédération Régionale de Défense contre les Organismes Nuisibles, FREDEC Midi-Pyrénées, Bt 43, 2 route de Narbonne, BP 12267, 31322 Castanet Tolosan, France
⁷ INRA, UMR 1224 ECOBIOP, 64310 Saint-Pée sur Nivelle, France

^* Corresponding author: catherine.regnault-roger@univ-pau.fr

Accepted: 26 January 2010

Abstract

Mycotoxins produced by Fusarium spp. during plant cultivation induce severe diseases in animal and humans. In 2007 a European Union regulation set maximum concentrations of mycotoxins in maize and derivatives of 4000 ppb for fumonisins B₁ and B₂, 1750 ppb for deoxynivalenol, and 350 ppb for zearalenone. To assess the safety of French maize food, investigations are currently being carried out by the national Biological Risk Monitoring network. Here, 84 plots were cropped with the Bt maize MON 810 and its isogenic non-Bt counterpart in 2005 and 2006 in Southwestern France. Mycotoxin levels were measured in grain at harvest. Fumonisins B₁ and B₂, deoxynivalenol, and zearalenone were analysed by liquid chromatography-mass spectrometry. The data were analysed statistically using non-parametric tests for mycotoxins and analysis of variance for weather variables. As the climate was homogenous inside the experimental area, the transgenic event introduced into the maize was the only key parameter which differed between Bt and non-Bt maize plots. Our results show that Bt maize decreased concentrations of fumonisins by 90% and zearalenone by 50%, whereas the concentration of deoxynivalenol was slightly increased. Those findings suggest a competition among Fusarium species that produce fumonisins or trichothecenes. According to the European regulation, 93% of the Bt maize crops can be sold, compared with only 45% for non-Bt maize plots. Our results thus show that Bt maize improved food safety by greatly reducing mycotoxin levels in field crops in Southwestern France.