Novel food information: Glufosinate ammonium tolerant canola (T45)

On this page:

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

Background

Health Canada has notified AgrEvo Canada Inc. that it has no objection to the food use of refined oil from canola lines derived from the genetically modified canola transformant designated T45, which is resistant to glufosinate ammonium. The Department conducted a comprehensive assessment of T45 derived canola lines 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 derived from genetically modified organisms.

The following provides a summary regarding the AgrEvo Canada Inc. notification to Health Canada and contains no confidential business information.

Introduction

Canola transformant T45 was developed through genetic modification to be tolerant to glufosinate ammonium, which is the active ingredient of the herbicide Liberty®. The modification permits farmers to use the broadspectrum herbicide for weed control in the cultivation of canola without damaging the crop.

Development of the modified plant

The T45 transformant was produced by Agrobacterium-mediated transformation of the canola (Brassica napus L.) Cultivar AC Excel with additional genetic material (DNA). The introduced DNA is based on the pat gene which was originally isolated from a common soil bacterium, Streptomyces viridochromogenes, and encodes the enzyme, phosphinothricin acetyltransferase (PAT). The gene inroduced in transformants T45 was modified to optimize its expression in plants without altering the amino acid sequence it encodes.

Molecular analysis of T45 plants indicated that a single copy of the transferred DNA was incorporated into the B. napus genome. The only gene transferred into the T45 transformant was the pat gene, and the integration of the transferred DNA was demonstrated to be stable.

Product information

Expression of the pat gene in T45 plants results in the production of the PAT protein in canola tissues at low levels (< 0.5 ppm). The PAT protein mediates the rapid metabolism of glufosinate ammonium. Analysis demonstrated that the PAT protein or its enzymatic activity could not be detected in the refined oil, the only canola product used for human consumption.

The only newly expressed material in T45-derived plants is the PAT protein. The PAT protein is an enzyme which is highly specific for glufosinate ammonium, and does not possess proteolytic or heat stability. PAT has been compared with known toxins and allergens in the GENBANK database which demonstrated that the amino acid sequence of the PAT protein did not share similarity with sequences of known toxins or allergens.

Dietary exposure

Human consumption of canola products is limited to the refined oil. The processing of refined canola oil destroys the enzymatic activity of the PAT protein. As indicated above (Section 3), PAT is not detected in the refined oil. As such, no human exposure to the introduced PAT protein is expected as a result of consumption of refined canola oil from T45-derived plants.

Nutrition

Compositional analyses of processed canola oil from T45-derived lines and current commercial canola cultivars were compared for fatty acids, glucosinolates, chlorophyll and phytsterol content. These comparisons indicated no statistically significant differences for the components analysed. The use of refined oil from T45-derived canola lines would therefore have no significant impact on the nutritional quality of the Canadian food supply.

Conclusion

Health Canada's review of the information presented in support of the food use of refined oil from glufosinate ammonium tolerant canola lines derived from the genetically modified canola transformant designated T45 concluded that such refined oil does not raise concerns related to safety. Health Canada is of the opinion that refined oil from T45-derived canola lines is as safe and nutritious as refined oil from current commercial canola varieties.

Health Canada's opinion deals only with the food use of refined oil from the genetically modified canola transformant designated T45. Issues related to growing T45-derived canola in Canada and its use as animal feed have been addressed separately through existing regulatory processes in Agriculture & Agri-Food Canada.

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