Summary of the Opinion

This document provides an opinion of the Scientific Panel on Genetically Modified Organisms (GMO Panel) of the European Food Safety Authority (EFSA) on Bt11 maize, genetically modified to provide protection against specific lepidopteran pests. The maize also contains a gene providing tolerance to the herbicide glufosinate.

The opinion is based on a question raised by the Commission relating to an application for the placing on the market of Bt11 maize under Directive 2001/18/EC. The GMO Panel was asked to consider whether there is any scientific reason to believe that placing Bt11 maize on the market, for cultivation, import, processing and use as any other maize (excluding food uses), is likely to cause any adverse effects on human health and the environment (Notification C/F/96/05.10). The question followed a scientific assessment which was made initially by the Competent Authority of France and evaluated subsequently by all other Member States. An assessment of the Bt11 maize was requested by the Commission because of questions raised by several Member States following the evaluations at the national level. When this is the case, EU legislation requires that EFSA carries out a further assessment and provides an opinion.

Bt11 maize has been previously evaluated (SCP, 1998a) and approved (EC, 1998) for import, processing and feed use under Directive 90/220/EEC. Bt11 maize has also been evaluated for cultivation under the same Directive (SCP, 2000). Food and food ingredients derived from Bt11 maize have been authorised (EC, 1999) pursuant to Article 5 of Regulation (EC) 258/97. Bt11 sweet maize has also been evaluated (SCF, 2002) and approved (EC, 2004c) for food consumption in the framework of Regulation (EC) 258/97 (EC, 1997).

In delivering its opinion the Panel considered the application, additional information provided by the applicant and comments submitted by the Member States. Bt11 maize was assessed with reference to its intended use employing the appropriate principles as described in the ‘Guidance Document of the Scientific Panel on Genetically Modified Organisms for the Risk Assessment of Genetically Modified Plants and Derived Food and Feed’ (EFSA, 2004a). The scientific assessment included examination of the DNA inserted into Bt11 maize and the nature and safety of the newly expressed proteins produced by the transgenic plants with respect to toxicology and allergenicity. Furthermore, a comparative analysis of agronomic traits and composition was undertaken and the safety of the whole product was evaluated. A nutritional and an environmental assessment, including monitoring plan, were both undertaken.

Bt11 maize has been developed for protection against specific lepidopteran pests such as the European corn borer (Ostrinia nubilalis) and Sesamia spp. Though the applicant considered that the pat gene for glufosinate ammonium tolerance was a marker gene and would only be used for that purpose, the Panel considered it likely that farmers would grow Bt11 maize with glufosinate herbicide applications. The Panel therefore decided that the environmental risk assessment and the post marketing environmental monitoring should also consider the direct and indirect impacts of the herbicide tolerance trait.

Insect resistance is achieved by production of a variant Cry1Ab protein from Bacillus thuringiensis and tolerance to the herbicide is conferred by a phosphinothricin-N-acetyltransferase (PAT) from Streptomyces viridochromogenes. Maize protoplasts were transformed with a DNA fragment containing two expression cassettes. As a result of the genetic modification, the Bt11 event contains an insert bearing both cry1Ab and pat genes, under the control of the 35S promoter.

Molecular analysis showed that Bt11 maize contains one copy of the DNA fragment used for transformation and that this is present at a single locus in the nuclear genome of the GM plant. The complete DNA sequence of the insert was provided. There is no evidence for the presence of partial insertions of amp gene sequences or non-coding vector backbone sequences. Analysis of DNA sequences flanking both ends of the insert shows that they correspond to maize genomic DNA. The insertion of the DNA fragment bearing both cry1Ab and pat genes does not disrupt any endogenous maize open reading frame. The genetic stability of the inserted DNA in event Bt11 was demonstrated and segregation data for the PAT and Cry1Ab traits were shown to follow Mendelian genetics.

Based on the results of compositional analysis, it is concluded that forage (silage) and kernels of Bt11 maize are compositionally equivalent to those of conventional maize, except for the presence of Cry1Ab and PAT proteins in Bt11 maize. No indications were found that unintended effects have occurred in Bt11 maize.

Notification C/F/96/05.10 concerns cultivation, import, processing and use as any other maize, excluding food uses. Bt11 maize is comparable with maize bred traditionally, except for the expression of tolerance to glufosinate herbicide and resistance to certain lepidopterans. Maize does not colonise and rarely survives outside the cultivated environment. It is winter-hardy only in parts of Southern Europe, and it has no cross-compatible wild relatives in Europe. Therefore, no unintended environmental effects due to the establishment and spread are anticipated. The likelihood of adverse effects on non-target organisms or on soil functions due to the expression of the cry1Ab gene or the pat gene is considered to be very low. The presence of the pat gene and the use of glufosinate ammonium are not likely to give an additional botanical diversity effect compared to other herbicides. The possible development of resistance of target organisms to Bt toxin has been identified as a potential risk due to large scale cultivation and/or long term exposure. Thus, an appropriate case-specific monitoring plan to record the development of resistance has been provided. In addition, the GMO Panel agrees in principle with the approach proposed by the applicant in the general surveillance plan.

From the data provided by the applicant, there was no evidence to indicate that Bt10 material was present in the Bt11 maize used for the biosafety studies. Therefore, the GMO Panel considers that the risk assessment of Bt11 maize has not been compromised by the presence of Bt10 maize.

In conclusion, the Panel considers that the information available for Bt11 maize addresses the outstanding questions raised by the Member States and considers that Bt11 maize will not have an adverse effect on human and animal health or the environment in the context of its proposed use.

Opinion in PDF format: http://www.efsa.eu.int/science/gmo/gmo_opinions/922/gmo_opinion_ej213_bt11maize_cultivation_en1.pdf