<p style="text-align: justify;"><b>Dietary exposure</b></p>

<p style="text-align: justify;">The modification to the AHAS enzyme in X81359 will not result in any change in the consumption or use pattern of sunflower oil and products derived from the oil and the meal. The oil and meal from X81359 are therefore expected to be used in applications similar to other sunflower and vegetable oils by the food and feed industry. X81359 is also the result of several backcrosses into NuSun sunflower lines. The oil from these sunflower lines have an altered fatty acid profile, and are termed &ldquo;mid-oleic.&rdquo; Due to this altered fatty acid profile, oil derived from Clearfield&trade; sunflower line X81359 will require a modified common name to differentiate the oil from traditional sunflower oils in the marketplace.</p>

<p style="text-align: justify;"><b>Nutritional and Compositional Data</b></p>

<p style="text-align: justify;">The nutritional composition of X81359 sunflower was assessed in whole sunflower grain and compared to comparator line, 8377NS, and other commercial sunflower cultivars. Samples for analysis were obtained from trials at six location years in the United States. The nutritional components included: crude protein, crude fat, crude fibre; branched chain amino acids (valine, isoleucine, leucine); essential amino acids (cysteine, methionine, threonine and lysine); B vitamins (thiamine, niacin, pantothenic acid, pyridoxine, riboflavin, and folic acid); minerals (phosphorus, zinc, magnesium and iron); vitamin E; and fatty acids. Statistically significant differences were observed in the levels of crude protein, threonine, tryptophan, calcium and magnesium. These differences were not biologically significant, and were within the normal range of variation reported for NuSun hybrids. Significant differences were observed in the levels of some fatty acids, such as stearic acid; however, these levels also fell within the ranges determined for other mid-oleic NuSun sunflower oils. The overall nutritional composition of X81359 was therefore determined to be equivalent to the comparator line 8377NS, and to commercial sunflower cultivars, including NuSun hybrids.</p>

<p style="text-align: justify;">The anti-nutrients phytic acid and trypsin inhibitor were measured in X81359 and 8377NS. Phytic acid occurs naturally in sunflower and in cereals. It is indigestible by humans and non-ruminant livestock, and inhibits the absorption of iron and other minerals. Trypsin inhibitor interferes with the enzymes involved in protein digestion. Phytic acid levels in X81359 were not different from those of the comparator line 8377NS, and levels of trypsin inhibitor in both lines were below the limit of detection.</p>

<p style="text-align: justify;"><b>Toxicity and Allergenicity</b></p>

<p style="text-align: justify;">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 has been reviewed previously by Health Canada and the Canadian Food Inspection Agency. 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.</p>

<p style="text-align: justify;">The AHAS enzyme does not possess the physicochemical properties of toxins and allergens, such as resistance to heat and trypsin degradation. The unmodified form of AHAS is heat sensitive and susceptible to trypsin degradation. Data from studies on the AHAS from X81359 demonstrated the inactivation of the enzyme after 1 minute of heating at 100&deg;C, and its complete degradation in trypsin within 60 minutes of exposure. The unmodified form of AHAS also shows no amino acid similarity to known toxins and allergens, and the modified AHAS differs by only one amino acid. Evidence was also provided to show that the protein components of X81359 were not altered compared to those of unmodified control. Results from HPLC on protein extracts demonstrated similar protein banding pattern in X81359 compared to the unmodified sunflower cultivars. The results of these investigations led to the conclusion that X81359 sunflower did not demonstrate any potential for toxicity and allergenicity compared to conventional unmodified sunflower.</p>
