Novel food information: Clearfield™ sunflower (helianthus annuus) line x81359

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Health Canada has notified BASF Canada that it has no objection to the food use of refined oil from Clearfield™ sunflower variety X81359, which is tolerant to imidazolinone herbicides. The Department conducted a comprehensive assessment of sunflower oil derived from X81359 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 novel foods.

The following provides a summary regarding BASF Canada's notification to Health Canada and contains no confidential business information.


BASF Canada developed Clearfield™ sunflower variety X81359 that is tolerant to imidazolinone herbicides by traditional plant breeding techniques. The basis for the herbicide tolerance is the expression in the sunflower plant of a mutant acetohydroxyacid synthase (AHAS).

Development and Production of the modified plant

Sunflower variety X81359 is a result of a cross between two imidazolinone tolerant parents and extensive backcrossing with commercial NuSun sunflower varieties. The herbicide tolerance trait is a natural mutation that was originally isolated from the wild sunflower populations by the United States Department of Agriculture. The target of the imidazolinone class of herbicides is the enzyme acetohydroxyacid synthase (AHAS) which is responsible for the first step in the biosynthesis of essential branched chain amino acids.

The imidazolinone tolerance trait in Clearfield™ sunflower X81359 is due to a point mutation of a single nucleotide in the AHAS gene. Previously authorized imidazolinone tolerant rice, corn, canola, and wheat lines were the result of single nucleotide substitutions in the AHAS gene. This single amino acid change alters the binding site for the herbicide on the AHAS enzyme expressed by AHAS gene while having no effect on the normal functioning of the enzyme.

Product information

A mutation in the AHAS enzyme in sunflower could affect the biosynthesis of the essential amino acids isoleucine, leucine, and valine. The amino acid composition of Clearfield™ sunflower was compared to commercial cultivars, confirming that the AHAS activity of the imidazolinone-tolerant sunflower was not affected by the mutation.

Dietary exposure

Clearfield™ sunflower oil is expected to be used in applications similar to other sunflower and vegetable oils by the food industry.


The nutrient data pertaining to Clearfield™ sunflower which produces a "mid-oleic" oil containing 55-75% oleic acid, comprised the analyses of antinutrients (phytic acid and trypsin inhibitor), proximates (crude fat, crude fibre, and protein), fatty acids, and vitamin E. Results showed no significant differences in antinutrients and proximates when comparing the X81359 sunflower grain and grain from the control variety 8377NS. The levels of fatty acids in the oil from Clearfield™ sunflower fell within the ranges found for other mid-oleic sunflower oils, also known as "NuSun". The results also demonstrate that there were no differences in vitamin E levels between Clearfield™ sunflower and parental varieties. Due to the altered fatty acid profile, oil derived from Clearfield sunflower line X81359 will require a modified common name to differentiate the oil from traditional sunflower oils in the marketplace.


The impact of single point mutations that confer tolerance of various plant AHAS to imidazolinone herbicides, on the toxic and allergenic potential of the protein have been considered in previous novel food notifications reviewed by Health Canada. No toxicological or allergenic concern was introduced at the level of exposure to AHAS in those products. In the case of oil produced from X81359 sunflower, extensive processing removes protein residues from the oil, and consequently, exposure to the mutated AHAS protein is expected to be negligible. There are no additional toxicity or allergenicity concerns with this product.


Health Canada's review of the information presented in support of the food use of mid-oleic sunflower oil derived from Clearfield™ sunflower variety X81359 concluded that this oil does not raise any concerns related to human food safety. Health Canada is of the opinion that processed oil from Clearfield™ sunflower X81359 is as safe and nutritious as that available from current commercial sunflower varieties.

Health Canada's opinion deals solely with respect to the suitability for sale as human food of refined oil from Clearfield™ sunflower line X81359.

The developer has indicated that Clearfield sunflower line X813359 will only be grown in the United States and sunflower meal derived from this line will not be sold to Canadian customers as livestock feed. Since line X81359 is an oilseed sunflower variety, it will only be used in the crushing industry for sunflower oil. No part of Clearfield sunflower line X81359 (i.e., plants, seeds, oil, meal, etc.) is authorized for environmental release leading to cultivation or livestock feed use in 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

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