Source: European Food Safety Authority
Opinion adopted on 14 September 2005 (Question No EFSA-Q-2005-003)

Summary

This document provides an opinion of the Scientific Panel on Genetically Modified Organisms (GMO Panel) of the European Food Safety Authority (EFSA) on oilseed rape Ms8, Rf3 and Ms8 x Rf3, genetically modified to introduce a pollination control system (hybrid system), linked with a tolerance to glufosinate-ammonium.

The opinion is based on a question raised by the Commission relating to an application (Ref. C/BE/96/01) from Bayer CropScience under Directive 2001/18/EC to place on the market oilseed rape Ms8, Rf3 and Ms8 x Rf3. The GMO Panel was asked to consider whether there is any scientific reason to believe that placing oilseed rape Ms8, Rf3 and Ms8 x Rf3 on the market for import, processing and uses as any other oilseed rape (excluding food uses), is likely to cause any adverse effects on human health and the environment. The question followed a scientific assessment which was made initially by the Competent Authority of Belgium and evaluated subsequently by all other Member States. An assessment of oilseed rape Ms8, Rf3 and Ms8 x Rf3 was requested by the Commission because of questions raised by several Member States following the evaluations at national level. When this is the case, EU legislation requires that EFSA carries out a further assessment and provides an opinion. In delivering its opinion the GMO Panel considered the application, additional information provided by the applicant and the specific questions and concerns raised by the Member States.

Oilseed rape lines Ms8, Rf3 and Ms8 x Rf3 were assessed with reference to their intended uses 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 oilseed rape Ms8, Rf3 and Ms8 x Rf3 and the nature and safety of the target proteins produced by the transgenic plants with respect to toxicology and allergenicity. Furthermore, a comparative analysis of agronomic traits and composition of Ms8 x Rf3 oilseed rape was undertaken and the safety of the whole feed was evaluated. A nutritional and an environmental assessment, including the import monitoring plan, were both undertaken.

The oilseed rape parental lines Ms8 and Rf3 have been developed for the production of hybrid seeds Ms8 x Rf3, combined with tolerance to the Liberty® herbicide (the active ingredient of which is glufosinate-ammonium/phosphinothricin). As a result of hybrid vigour cross-pollinated plants produce higher yield as compared to self-pollinated oilseed rape. The hybrid system is achieved using a pollination control system by insertion and expression of barnase and barstar genes from Bacillus amyloliquefaciens into two separate oilseed rape lines. Oilseed rape embryos were transformed by Agrobacterium tumefaciens to transfer DNA fragments containing these genes. The barnase and barstar genes are each linked with the bar gene from Streptomyces hygroscopicus which encodes the enzyme phosphinothricin acetyltransferase (PAT) and which confers. tolerance to the herbicide glufosinate ammonium. Conventional crossing of the two GM lines is used to produce the Ms8 x Rf3 seeds.

The female line Ms8 (Male sterile) contains an insert bearing both barnase and bar genes, under the control of tapetum cell-specific PTA29 and PssuAra promoters, respectively. The barnase gene encodes a ribonuclease peptide (RNase) expressed only in the tapetum cells during anther development. The RNase affects RNA levels, disrupting normal cell functioning and arresting early anther development, thus leading to the lack of viable pollen and male sterility.

The male line Rf3 (Restorer of fertility) contains an insert bearing both barstar and bar genes, under the control of, respectively, tapetum cell-specific PTA29 and PssuAra promoters. The barstar gene codes for a ribonuclease inhibitor (Barstar peptide) expressed only in the tapetum cells of the pollen during anther development. The ribonuclease inhibitor (Barstar peptide) specifically inhibits the Barnase RNase expressed by the Ms8 line.

Together, the RNase and the ribonuclease inhibitor form a very stable one-to-one complex, in which the RNase is inactivated. As a result, when pollen from the restorer line Rf3 is crossed to the male sterile line Ms8, the resultant Ms8 x Rf3 progeny expresses the RNase inhibitor in the tapetum cells of the anthers allowing hybrid plants to develop normal anthers and restore fertility.

Appropriate molecular techniques were used to characterise the transformation events leading to the production of Brassica napus lines Ms8 and Rf3. Southern hybridisation was used to detect and characterise the transformation events, to establish the absence of unwanted vector sequences and to identify the transgenic lines. PCR analysis was used to characterise further the transgenic events and to determine the nucleotide sequences of the plant DNA flanking the inserts. Northern analysis was used to quantify transgene transcript levels in leaves, seeds and pollen. Western analysis was used to detect the protein products. ELISA and enzymatic method were used to detect and quantify the PAT protein and its activity. The DNA sequences of the insert in the hybrid Ms8 x Rf3 were investigated using PCR and DNA sequencing confirming that gross insert structures and insertion loci were retained.

The extensive comparative compositional analysis of Ms8 x Rf3 seeds from field trials in Europe (Belgium) showed that there was no indication of unintended effects of the genetic modification. Additional animal safety or nutritional studies are not necessary. Ms8 x Rf3 oilseed rape was considered comparable with conventional oilseed rape, except for the expression of the new proteins.

The application C/BE/96/01 for oilseed rape lines Ms8, Rf3 and Ms8 x Rf3 was only assessed for the import and processing of Ms8 x Rf3 seeds for feed and industrial uses. Therefore the GMO Panel did not assess the scientific informationon possible environmental effects associated with the cultivation of oilseed rape Ms8, Rf3 and Ms8 x Rf3. The GMO Panel agrees with the conclusions of the environmental risk assessment by the applicant that the likelihood of unintended environmental effects due to the adventitious release and spread of Ms8, Rf3 and Ms8 x Rf3 oilseed rape will not be different from that of oilseed rape bred traditionally. The import monitoring plan provided by the applicant is in line with the intended uses of the GMO.

In conclusion, the GMO Panel considers that the information available for oilseed rape Ms8, Rf3 and Ms8 x Rf3 addresses the outstanding questions raised by the Member States and therefore the placing on the market of Ms8, Rf3 and Ms8 x Rf3 oilseed rape for import and processing for feed and industrial purposes is unlikely to have an adverse effect on human or animal health or, in the context of its proposed uses, on the environment. This is in addition to the present uses of oil for food purposes and processed meal for feed purposes, both derived from Ms8 x Rf3 oilseed rape, which are already lawfully placed on the market.

The Panel advises that appropriate management systems are in place to minimize accidental loss and spillage of transgenic oilseed rape during transportation, storage, handling in the environment and processing into derived products

Opinion in PDF format: http://www.efsa.eu.int/science/gmo/gmo_opinions/1178/gmo_op_ej281_ms8xrf3_1.pdf