Novel food information: Insect resistant glyphosate tolerant maize event MON 88017

On this page

• Background
• Introduction
• Development of the modified plant
• Characterization of the modified plant
• Product information
• Dietary exposure
• Nutrition
• Toxicology
• Conclusion 

Background

Health Canada has notified Monsanto Canada Inc. that it has no objection to the sale of food derived from corn lines containing the transformation event MON 88017, which exhibit both the YieldGard® Rootworm and Roundup Ready® traits. The Department conducted a comprehensive assessment of this corn event according to its Guidelines for the Safety Assessment of Novel Foods (September, 1994). These Guidelines are based upon internationally accepted principles for establishing the safety of foods with novel traits.

The following provides a summary of the notification from Monsanto, and the evaluation by Heath Canada and contains no confidential business information.

Introduction

Monsanto has developed corn (Zea mays) lines based upon transformation event MON 88017. Corn plants containing this vector-stacked^{Footnote 1} trait event express two novel proteins: the CP4 5-enolpyruvylshikimate-3-phosphate (CP4 EPSPS) protein which confers tolerance to glyphosate herbicides (many marketed as Roundup® brand), and the Cry3Bb1 protein which exhibits insecticidal activity against certain Coleopteran pests such as corn rootworms (Diabrotica sp.).

Health Canada has previously indicated no objection to the sale of the single trait Roundup Ready® corn event NK-603 expressing the CP4 EPSPS enzyme for human food applications. Health Canada has also previously indicated no objection to the sale of the single trait YieldGard® Rootworm corn event MON 863 expressing a variant of the Cry3Bb1 protein for human food applications.

The safety assessment performed by Food Directorate evaluators was conducted according to Health Canada's Guidelines for the Safety Assessment of Novel Foods. The assessment considered: how corn event MON 88017 was developed; how the composition and nutritional quality of corn grain derived from plants containing this event compare to non-modified corn; and what the potential is for food products derived from plants containing this event to be toxic or cause allergic reactions.

The Food Directorate has a legislated responsibility for pre-market assessment of novel foods and novel food ingredients as detailed in Division 28 of Part B of the Food and Drug Regulations (Novel Foods). Foods derived from corn lines containing event MON 88017 are considered novel foods under the following part of the definition of novel foods: "c) a food that is derived from a plant, animal or microorganism that has been genetically modified such that

1. the plant, animal or microorganism exhibits characteristics that were not previously observed in that plant, animal or microorganism"

Development of the modified plant

Corn event MON 88017 was developed through Agrobacterium-mediated transformation of corn embryo derived tissue followed by negative selection on culture media containing the herbicide glyphosate. MON 88017 is a single insertional event containing two tandem expression cassettes, one for the cp4-epsps gene and one for the cry3Bb1 gene:

The cp4 epsps gene is fused to a chloroplast transit peptide (ctp2) sequence that targets the CP4 EPSPS protein to the chloroplasts, the site of aromatic amino acid synthesis. Constitutive expression of cp4 epsps was controlled by the rice actin 1 promoter (P-ract1), the rice actin 1 intron sequence (I-ract1) for gene transcript stability, and 3' nopaline synthase polyadenylation sequence from Agrobacterium tumefaciens (nos 3').

A modified version of the CaMV 35S promoter containing a duplicated enhancer region (P-e35S) was used to control the constitutive expression of a synthetic variant of the cry3Bb1 gene from Bacillus thuringiensis subsp. kumamotoensis. The 5' untranslated leader sequence from the wheat chlorophyll a/b-binding protein (L-wt CAB) and the rice actin 1 intron sequence (I-ract1) was used to stabilize levels of gene transcription. The polyadenylation sequence is derived from the 3' nontranslated region of the wheat 17.3 kDa heat shock protein (tahsp17 3').

Characterization of the modified plant

Southern blot and PCR analysis of corn containing the event MON 88017 demonstrated the insertion of one copy of the T-DNA of plasmid PV-ZMIR39 in the corn genome. Southern blot analysis also demonstrated the integrity of the cp4-epsps and cry3Bb1 genes and regulatory elements, as well as the absence of plasmid-derived sequences outside of the T-DNA region.

The genetic stability of the inserted cp4-epsps and cry3Bb1 gene cassettes was evaluated in different corn germplasm backgrounds over seven generations of conventional breeding at various locations. The results obtained demonstrate the heritability and stability of the event MON 88017 at the genomic level.

Product information

Corn event MON 88017 differs from its traditional counterparts by the addition of the cp4-epsps and cry3Bb1 gene sequences into the genome, and the expression of the CP4 EPSPS and Cry3Bb1 proteins. The proteins encoded by these two genes are expressed at different levels throughout the plant tissue and throughout the life of the plant.

Dietary exposure

The levels of Cry3Bb1 and CP4 EPSPS proteins represent approximately 0.01 % and 0.004 % of total protein in MON 88017 grain sampled from four commercial hybrids at three field sites. It is expected that grain from MON 88017 will be used in applications similar to that derived from other field corn varieties. In North America, corn based food products for human consumption are found mainly in the form of processed foods containing corn derived ingredients such as high fructose corn syrup, starch, oil, and flour.

Nutrition

The analysis of nutrients from corn lines containing event MON 88017, control, and conventional corn did not reveal any significant differences in the levels of protein, fat, ash, moisture, carbohydrates, fibre, amino acids, fatty acids, minerals, vitamins, anti-nutrients, and secondary metabolites. In each case the level of each respective component was comparable to the control or within the reported range for conventional corn. The consumption of products from corn event MON 88017 will have no significant impact on the nutritional quality of the Canadian food supply.

Toxicology

The potential for toxicity for CP4 EPSPS and Cry3Bb1 proteins expressed in corn lines containing event MON 88017 was considered remote. This conclusion was based on the low amount of CP4 EPSPS and Cry3Bb1 proteins found in corn grain, the absence of demonstrated acute toxicity to CP4 EPSPS and Cry3Bb1 in mice at doses orders of magnitude greater than the range associated with proteins, the lack of sequence homology between known toxins and the CP4 EPSPS and Cry3Bb1 proteins, and the likelihood that the CP4 EPSPS and Cry3Bb1 proteins will be degraded under conditions similar to those in the human gastrointestinal tract. There were no additional health concerns regarding endogenous toxins from food products derived from corn lines containing event MON 88017 when compared to non-transgenic varieties.

The possibility that the CP4 EPSPS and Cry3Bb1 proteins would be allergenic in corn lines containing event MON 88017 was also considered unlikely. This was based on the lack of sequence homology of the CP4 EPSPS and Cry3Bb1 proteins to any known allergens, and the rapid digestion of both two proteins in simulated gastric and intestinal fluids. These results suggest that foods derived from corn lines containing event MON 88017 would not pose any greater allergenic risk than non-transgenic corn.

At the expected level of consumption, there was no greater concern with corn lines containing event MON 88017 than non-transgenic corn, with respect to its potential for toxicity or allergenicity.

Conclusion

Health Canada's review of the information presented in support of the food use of corn lines containing event MON 88017 concluded that the food use of corn lines containing this event does not raise concerns related to safety. Health Canada is of the opinion that corn lines containing event MON 88017 are as safe and nutritious as current commercial corn lines.

Health Canada's opinion deals only with the human food use of corn lines containing event MON 88017. Issues related to its use as livestock feed have been addressed separately through existing regulatory processes in the Canadian Food Inspection Agency.

This Novel Food Information document has been prepared to summarize the opinion regarding the subject product provided by the Food Directorate, Health Products and Food Branch, Health Canada. This opinion is based upon the comprehensive review of information submitted by the petitioner according to the Guidelines for the Safety Assessment of Novel Foods (September 1994).

For further information, please contact:

Novel Foods Section
Food and Nutrition Directorate
Health Products and Food Branch
Health Canada, PL2204A1
251 Frederick Banting Driveway
Ottawa, Ontario K1A 0K9
bmh-bdm@hc-sc.gc.ca