Lower mycotoxin levels in Bt maize grain

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 B 1 and B 2 , 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 B 1 and B 2 , 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.Bt MON810 maize / fumonisins B 1 and B 2 / deoxynivalenol / zearalenone / Regulation 1126/2007

Bt crops and food security in developing countries: realised benefits, sustainable use and lowering barriers to adoption

“…Reduction in physical injury to stems and kernels of Bt maize by lepidopterous pests has reduced the level of secondary fungal infections, thus reducing the accumulation of mycotoxins produced by those fungi. This reduction has been observed in studies from the US and other countries (Munkvold et al 1999;Williams et al 2002;Hammond et al 2004;de la Campa et al 2005;Brookes 2008;Folcher et al 2010;Ostry et al 2010). The clearest evidence for reduction is in the fumonisin mycotoxins; however, Bt maize also appears to have the potential to reduce aflatoxin, deoxynivalenol and zearalenone (Wu 2007).…”

Genetic Engineering and Sustainable Crop Disease Management: Opportunities for Case-by-Case Decision-Making

“…Another benefit from the use of Bt corn has been the well-documented reductions in mycotoxin contamination that sometimes occur. Reductions in both fumonisins and aflatoxins have been reported in field studies on several continents [111][112][113][114][115]. These reductions have been associated with reduced insect wounding on kernels expressing a Cry endotoxin, resulting in fewer openings for infection by mycotoxin-producing fungi [114,116].…”

Withdrawal of maize protection by herbicides and insecticides increases mycotoxins contamination near maximum thresholds

“…The AFNOR V03-110 protocol from the French agency for product standardization was used. Details of the protocol applied are available in Folcher et al (2010).…”

“…As a result, little is known about the responses of particular pest to the presence of other pest species. One clear exception is the amplifying impact of insect foraging galleries on the occurrence of Fusarium species Sobek and Munkvold 1999), potentially resulting in higher levels of mycotoxin contamination (Bakan et al 2002;Avantaggiato et al 2002;Folcher et al 2010).…”