DD2008-70: Determination of the Safety of Syngenta Seeds Inc.'s Corn (Zea mays L.) Event 3272

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Issued: 2008-03

This Decision Document has been prepared to explain the regulatory decision reached under Directive 94-08 (Dir94-08), entitled "Assessment Criteria for Determining Environmental Safety of Plants with Novel Traits", its companion biology document BIO1994-11, "The Biology of Zea mays L. (Corn/Maize)", and Directive 95-03 (Dir95-03), entitled "Guidelines for the Assessment of Novel Feeds: Plant Sources".

The Canadian Food Inspection Agency (CFIA) has evaluated information submitted by Syngenta Seeds Inc. This information is in regard to corn event 3272 expressing a thermostable alpha-amylase. The CFIA has determined that this plant with a novel trait (PNT) does not present altered environmental risk nor, as a novel feed, does it present livestock feed safety concerns when compared to currently commercialized corn varieties in Canada.

Taking into account these evaluations, unconfined release into the environment and use as livestock feed of corn event 3272 is therefore authorized by the Plant Biosafety Office of the Plant Health and Biosecurity Directorate and the Animal Feed Division of the Animal Health Directorate as of March 11, 2008. Any corn lines derived from event 3272 may also be released into the environment and used as livestock feed, provided that (i) no inter-specific crosses are performed, (ii) the intended uses are similar, (iii) it is known based on characterization, that these plants do not display any additional novel traits and are substantially equivalent to currently grown corn varieties in Canada, in terms of their potential environmental impact and livestock feed safety and (iv) the novel genes are expressed at a level similar to that of the authorized line.

Corn event 3272 is subject to the same phytosanitary import requirements as its unmodified counterpart.

Please note that the assessment of livestock feed safety and environmental safety are critical steps in the potential commercialization of these plant types. Other requirements, such as the evaluation of food safety by Health Canada, have been addressed separately from this review.

Table of Contents

I. Brief Identification of the Modified Plant

II. Background Information

III. Description of the Novel Trait

  1. Expression of a Thermostable Alpha-Amylase
  2. Expression of Phosphomannose Isomerase
  3. Development Method
  4. Stable Integration into the Plant Genome

IV. Assessment Criteria for Environmental Safety

  1. Potential of Corn event 3272 to Become a Weed of Agriculture or be Invasive of Natural Habitats
  2. Potential for Gene Flow from Corn event 3272 to Wild Relatives Whose Hybrid Offspring May Become More Weedy or More Invasive
  3. Altered Plant Pest Potential of Corn event 3272
  4. Potential Impact of Corn event 3272 on Non-Target Organisms
  5. Potential Impact of Corn event 3272 on Biodiversity

V. Criteria for the Livestock Feed Assessment

  1. Potential Impact of Corn event 3272 on Livestock Nutrition
  2. Potential Impact of Corn event 3272 on Livestock and Workers/Bystanders

VI. New Information Requirements

VII. Regulatory Decision

I. Brief Identification of the Modified Plant

Designation of the Modified Plant: Corn Event 3272, OECD Unique Identifier SYN-E3272-5

Applicant: Syngenta Seeds Canada Inc.

Plant Species: Maize (Zea mays L.)

Novel Traits: Expression of a thermostable alpha amylase for use in the dry-grind ethanol production from maize grain.

Trait Introduction Method: Agrobacterium-mediated transformation

Proposed Use of the Modified Plant: Production of grain for use in the dry-grind ethanol process. By-products of the dry-grind ethanol process for use as livestock feed. These plants are not intended to be grown outside the normal production area for corn in Canada.

II. Background Information

Syngenta Seeds Inc. developed, through the use of recombinant DNA techniques, a corn event expressing a thermostable alpha-amylase in grain. The corn event, designated as 3272, was developed to provide a source of amylase enzyme in the dry-grind ethanol process, replacing the addition of microbially-produced enzymes.

Corn event 3272 was developed using recombinant DNA technology, resulting in the introduction of the amy797E gene and the pmi marker gene. The amy797E gene is derived from alpha-amylase genes from three hyperthermophilic microorganisms of the archaeal order Thermococcales. The amy797E gene encodes a thermostable AMY797E alpha-amylase enzyme which catalyses the hydrolysis of starch by cleaving the internal alpha-1,4-glucosidic bonds into dextrins, maltose and glucose. The pmi gene from Escherichia coli encodes the phosphomannose isomerase (PMI) enzyme. Expression of the PMI enzyme allows the plant to utilize mannose as a carbon source. This trait is of no agronomic or livestock feed interest but was used to select transformed from non-transformed plants during the development phase of corn event 3272.

Syngenta Seeds Inc. has provided data on the identity of corn event 3272, a detailed description of the transformation method, data on the gene insertion site, gene copy number and levels of gene expression in the plant and the role of the inserted genes and regulatory sequences. The novel proteins were identified and characterized. Data was provided for the evaluation of the potential toxicity of the novel proteins to livestock and non-target organisms and potential allergenicity of the novel proteins to humans and to livestock.

Corn event 3272 was field tested in the United States and the data for two trial years were submitted.

Agronomic characteristics of corn event 3272 such as days to 50% emergence, percent emerged plants, heat units to 50% silking, heat units to 50% pollen shed, % barren plants, grain yield, plant population at harvest, % dropped ears, test weight, grain moisture, early root lodging, % snapped plants, late season intactness, late root lodging, push test and % broken stalks, early emergence vigour, early growth rating, ear height, and plant height were compared to those of unmodified corn counterparts. Responses to insects and diseases were also observed.

Nutritional components of corn event 3272, such as proximates, amino acids and fatty acids were compared with those of unmodified corn counterparts.

The Biotechnology Environmental Release Assessment (BERA) Unit of the Science Strategies Directorate, CFIA, has reviewed the above information, in light of the assessment criteria for determining environmental safety of PNTs, as described in the Directive 94-08 (Dir94-08), entitled "Assessment Criteria for Determining Environmental Safety of Plants With Novel Traits". The BERA Unit has considered:

  • potential of corn event 3272 to become a weed of agriculture or be invasive of natural habitats;
  • potential for gene flow from corn event 3272 to wild relatives whose hybrid offspring may become more weedy or more invasive;
  • potential for corn event 3272 to become a plant pest;
  • potential impact of corn event 3272 or its gene products on non-target species, including humans; and
  • potential impact of corn event 3272 on biodiversity.

The Animal Feed Division of the Animal Health Directorate, CFIA, has also reviewed the above information with respect to the assessment criteria for determining the safety and efficacy of livestock feed, as described in Directive 95-03 (Dir95-03), entitled "Guidelines for the Assessment of Novel Feeds: Plant Sources". The Animal Feed Division has considered:

  • potential impact of corn event 3272 on livestock nutrition; and
  • potential impact of corn event 3272 on livestock and workers/bystanders

Syngenta Seeds Inc. has provided the CFIA with a method for the detection and identification of corn products containing the corn event 3272.

III. Description of the Novel Trait

1. Expression of a Thermostable Alpha-Amylase

Alpha-amylases catalyse the hydrolysis of starch by cleaving the internal alpha-1,4-glucosidic bonds of starch into dextrins, maltose and glucose. Microbially-produced alpha-amylases are commonly used in the starch-hydrolysis step during dry-grind corn processing. Amylases for this industry should work at high temperatures and have low calcium requirements. The AMY797E alpha-amylase expressed in grain of corn event 3272 was engineered for increased heat-stability and activity at the high temperatures required for starch hydrolysis in the dry-grind ethanol production from maize grain. Corn event 3272 grain will serve as the source of amylase enzyme in the dry-grind ethanol production, replacing the addition of microbially-produced enzymes. The chimeric amy797E gene was assembled from the sequences of three wild-type alpha-amylase genes from the archaeal order Thermococcales and was optimized to accommodate the preferred codon usage for maize. The amy797E gene includes sequences coding for a 19 amino-acid N-terminal signal peptide and a C-terminal endoplasmic reticulum retention signal for targeting to and retention of the AMY797E protein in the endoplasmic reticulum of the cell, respectively. The N-terminal signal peptide is cleaved from the precursor protein to yield the mature AMY797E protein.

The amy797E gene is expressed in event 3272 using a promoter which confers specific expression of the AMY797E protein in the endosperm of the kernel. Tissue samples were collected at various growth stages from two event 3272 hybrids grown at a representative US field trial site. Levels of AMY797E protein were evaluated by enzyme-linked immunosorbent assays. Average AMY797E levels in kernels of both hybrids across all growth stages, expressed in micro-grams protein per gram dry weight tissue ( g/g dwt), ranged from 1,004 to 3,365 g/g dwt, with the highest concentrations measured at the dough stage of kernel development. AMY797E protein was not detected in pollen or leaves. Only very low levels were detected in some whole plant and root samples at the whorl and anthesis stages.

The AMY797E protein expressed in corn event 3272 was purified from kernels and characterized. The identity of the purified protein was confirmed by Western immunoblot analysis, N-terminal amino-acid sequencing and measurement of alpha-amylase activity.

The high levels of expression of AMY797E protein in corn event 3272 kernels allowed purification of sufficient quantities of AMY797E protein directly from kernels for subsequent use in acute toxicity testing and digestibility studies.

The potential mammalian toxicity and allergenicity of the AMY797E protein was evaluated. Heat-stability, taken on its own, is not sufficient to classify the AMY797E protein as potentially toxic or allergenic. Syngenta Seeds Inc. investigated amino acid sequence homology of AMY797E protein with known protein toxins and allergens. The AMY797E protein lacks sequence similarity to known toxins. There is one region of sequence homology of 8 contiguous identical amino acids between the AMY797E protein and a known allergen, Per a 3 from the American cockroach. The IgE-binding epitopes of Per a 3 have been identified (Wu et al., 2003) and there is no overlap between these binding epitopes and the region of sequence homology with AMY797E protein. Therefore, the observed sequence identity is not biologically relevant and has no implication for the allergenic potential of the AMY797E protein. The AMY797E protein does not possess significant amino acid sequence similarities to other allergens. In vitro digestive fate studies have shown that the protein is rapidly degraded in simulated gastric fluid, unlike protein allergens which are normally resistant to digestion. The AMY797E protein expressed in event 3272 is not glycosylated, unlike many known allergens, providing additional evidence that AMY797E protein does not have the properties of known allergens. In addition, no biologically significant adverse effects were observed when AMY797E protein was ingested by mice at a single gavage dose of 1,511 mg/kg body weight. Therefore, based on the weight-of-evidence, the AMY797E protein expressed in event 3272 is unlikely to be toxic or allergenic to mammals.

2. Expression of Phosphomannose Isomerase

The pmi gene from Escherichia coli, which encodes the enzyme phosphomannose isomerase (PMI) was introduced in corn event 3272. Expression of PMI was used as a selectable marker during the process of developing corn event 3272. Maize cells producing PMI can utilize mannose as a primary carbon source, whereas cells lacking the pmi gene fail to proliferate in a mannose-based culture medium. Expression of the PMI protein is of no agronomic, livestock feed or industrial interest and was only used during the process of regenerating plant material following transformation.

The pmi gene expressed in corn event 3272 is linked to a constitutive promoter. Tissue samples were collected at various growth stages from two 3272 corn hybrids grown at a representative US field trial site. PMI protein was detected at low levels in most plant tissues analyzed. The highest mean levels were detected in pollen (ca. 18 g/g dwt) and in leaf tissues between whorl and kernel dough stages (8.8-17.1 g/g dwt).

Due to low expression of PMI protein in corn event 3272, it was not feasible to extract sufficient amounts of PMI protein from plant tissues for safety studies. It was necessary to express the pmi gene in an E. coli production system to obtain sufficient quantities of PMI protein. Compared to the PMI protein produced in corn event 3272, the PMI protein produced in E. coli contains 16 additional amino-acids at the N-terminus of the protein (derived from the expression vector). The equivalency of the 3272 corn-produced PMI protein to the E. coli-produced PMI was evaluated by comparing their molecular weight, immunoreactivity and enzymatic activity. Based on the results, both proteins were found to be nearly equivalent, with no significant differences.

The potential toxicity and allergenicity of the PMI protein was evaluated. It is likely that small amounts of PMI proteins from various sources have always been present in the food and feed supply due to the ubiquitous occurrence of PMI proteins in nature, including bacteria, yeast, food plants and animals. PMI proteins are present in many mammalian tissues and in humans. Syngenta Seeds Inc. investigated amino acid sequence homology of PMI protein produced in corn event 3272 with known protein toxins and allergens. PMI protein does not possess significant amino acid sequence similarities to known toxins. There is one region of sequence homology of 8 contiguous identical amino acids between the PMI protein and a known allergen, alpha-parvalbumin from Rana species. Further investigation using serum from a patient allergic to alpha-parvalbumin demonstrated that this sequence identity is not biologically relevant and has no implication for the potential allergenicity of the PMI protein. The PMI protein does not possess significant amino-acid sequence similarities to other allergens. In vitro digestive fate studies have shown that the PMI protein is rapidly degraded in simulated gastric and intestinal fluids, unlike protein allergens which are normally resistant to digestion. The PMI protein is inactivated following incubation at 65ºC for 30 minutes, providing additional evidence that PMI protein is unlikely to be a toxin or an allergen. Furthermore, no adverse effects were observed when the E. coli-produced PMI protein was ingested by mice at a dose of 3,080 mg/kg body weight. Therefore, based on the weight-of-evidence, the PMI protein expressed in event 3272 is unlikely to exhibit mammalian toxicity or allergenicity.

3. Development Method

The amy797E and pmi genes were introduced in corn event 3272 via Agrobacterium-mediated transformation of immature maize embryos derived from a proprietary maize line. Embryos producing embryogenic callus were transferred to cell culture medium containing mannose. Event 3272 was identified as a successful transformant and was chosen for further development.

4. Stable Integration into the Plant Genome

Molecular characterization by Southern blot analysis demonstrated that corn event 3272 contains single intact copies of the amy797E and pmi gene cassettes inserted at a single site in the corn genome. No additional elements, including intact or partial DNA fragments of the amy797E or pmi cassette or backbone sequences from the plasmid vector, linked or unlinked to the intact insert, were detected in corn event 3272. Sequencing of the introduced DNA confirmed the sequence and organization of the genetic elements and revealed that some truncation occurred at the right border and left border of the insert. These deletions have no effect on the functionality of the DNA insert and this phenomenon has been previously observed with Agrobacterium transformation.

The stability of the DNA insert was demonstrated by Southern blot analysis across three backcross generations. The inheritance pattern of the amy797E gene across four segregating backcross generations of event 3272 showed that the amy797E gene segregates according to Mendelian rules of inheritance for a single genetic locus. Concentrations of AMY797E and PMI proteins in event 3272 leaf and grain tissues, respectively, were measured across four backcross generations. The results indicate stability of AMY797E and PMI protein expression across generations.

IV. Assessment Criteria for Environmental Safety

1. Potential of Corn event 3272 to become a Weed of Agriculture or be Invasive of Natural Habitats

The biology of corn, described in the CFIA Biology Document BIO1994-11, shows that unmodified plants of this species are not invasive of unmanaged habitats in Canada. Corn does not possess the potential to become weedy due to the lack of seed dormancy, the non-shattering nature of corn cobs and the poor competitive ability of seedlings. According to the information provided by Syngenta Seeds Inc., corn event 3272 was determined to be similar to unmodified corn in this respect.

Event 3272 corn hybrids were tested at 8 locations in 2003 and 17 locations in 2004 in the United States corn belt. A total of 26 agronomic traits were evaluated. These agronomic traits covered a broad range of characteristics that encompass the entire life cycle of the maize plant and included data assessing seedling emergence, vegetative vigour, basic morphology, growth habit, time to reproduction, susceptibility to European corn borer and gray leaf spot, and yield characteristics. For the majority of agronomic traits, no statistically significant differences between 3272 hybrids and their non-transformed isogenic counterparts were observed. Although instances of statistically significant differences between 3272 and control hybrids were observed for some traits, there were no consistent trends in the data across locations, 3272 corn hybrids or years that would indicate that any of these differences were due to the genetic modification. Susceptibility to the European corn borer (ECB) could not be thoroughly evaluated due to very low ECB infestation levels. Similarly, susceptibility to Northern corn leaf blight, Southern corn leaf blight, and other diseases could not be evaluated due to a lack of naturally present disease inoculum. However, no change in response to pests or pathogens is anticipated from the expression of the AMY797E and PMI proteins in corn event 3272. Furthermore, trial observations showed that susceptibility of 3272 corn hybrids to gray leaf spot disease is unchanged compared to control hybrids.

The results showed no biologically meaningful differences between corn 3272 hybrids and their isogenic non-transgenic counterparts. No competitive advantage was conferred to corn event 3272 by the expression of the AMY797E and PMI proteins. The introduction of these novel traits did not make corn 3272 weedy or invasive of natural habitats since none of the corn reproductive or growth characteristics were modified, and corn 3272's tolerance to disease was unchanged.

The above considerations led the CFIA to conclude that corn event 3272 has no increased weediness or invasiveness potential compared to currently commercialized corn varieties.

2. Potential for Gene Flow from Corn event 3272 to Wild Relatives Whose Hybrid Offspring May Become More Weedy or More Invasive

The biology of corn, as described in CFIA Biology Document BIO1994-11, indicates that there are no wild relatives in Canada that can hybridize with corn. None of the data submitted by Syngenta Seeds Inc. on corn 3272 indicated any potential for a change in sexual compatibility as a result of the genetic modification.

The CFIA has therefore concluded that gene flow from corn event 3272 to wild relatives is not possible in Canada.

3. Altered Plant Pest Potential of Corn event 3272

The expression of the AMY797E alpha-amylase and PMI phosphomannose isomerase is unrelated to plant pest potential, and corn is not considered a plant pest in Canada. Corn event 3272 is not expected to exhibit modified response to diseases and pest insects, compared to unmodified corn counterparts. Furthermore, field evaluation of 3272 corn hybrids did not show any increase or decrease in susceptibility to gray leaf spot disease.

The CFIA has, therefore, determined that the corn event 3272 does not display any altered pest potential compared to currently commercialized corn varieties.

4. Potential Impact of Corn event 3272 on Non-Target Organisms

The AMY797E protein is not homologous to known toxins. A single-dose oral toxicity study showed that the AMY797E protein is not toxic to the mouse at a dose of 1,511 mg/kg body weight. This dose represents about 2.1 times the worst-case daily dietary dose for rodents eating a diet comprising 100% kernels of corn event 3272 in the field. Alpha-amylases of varying degrees of amino-acid homology with AMY797E protein occur widely in nature among prokaryotes and eukaryotes. Alpha-amylase enzymes are present in plants, including corn. Alpha-amylase enzymes are also found in human saliva. There is an enormous diversity of alpha-amylases in soil microorganisms, including many heat-stable alpha-amylases. Therefore, it is likely that mammals, birds, insects and microorganisms exposed to AMY797E protein expressed in corn event 3272 have had prior exposure to alpha-amylases. No harmful effects of such exposure is known.

Furthermore, as AMY797E protein is not detectable in pollen of 3272 corn, 3272 corn poses no risk to pollinators and non-target pollen consumers.

The kernel-specific expression of the protein in corn event 3272, the lack of detectable mammalian toxicity of AMY797E, and the weight of evidence that alpha-amylases are not toxic to other wildlife, indicates minimal risk to non-target organisms resulting from exposure to AMY797E protein in corn event 3272.

Phosphomannose isomerase is a ubiquitous enzyme involved in carbohydrate metabolism. Phosphomannose isomerases of varying degrees of amino acid homology to PMI expressed in corn event 3272 occur widely in nature. Phosphomannose isomerases have been detected in some crop species, mammals, humans, yeast, fungi and bacteria. Species that will be exposed to PMI from 3272 corn tissues are highly likely to have prior exposure to similar PMI proteins. No harmful effects of such exposure are known or expected. The PMI protein expressed in corn event 3272 is not homologous to any known toxins. Additionally, the bacterially-expressed PMI protein showed a lack of acute toxicity to the mouse at a single oral dose of 3,080 mg PMI/kg body weight. Therefore, no adverse effects on organisms exposed to the PMI protein expressed in corn event 3272 are anticipated.

Composition analyses showed that the levels of key nutrients in corn 3272 grain and forage and the levels of anti-nutrients in corn 3272 grain are comparable to those in commercial corn varieties.

Based on the above, the CFIA has determined that, compared to current commercial corn varieties, the unconfined release of corn event 3272 will not result in altered impacts on non-target organisms, including humans.

5. Potential Impact of Corn event 3272 on Biodiversity

Corn event 3272 has no novel phenotypic characteristics that would extend its range beyond the current geographic range of corn production in Canada. Corn event 3272 is not more weedy or invasive than conventional corn. Since corn has no wild relatives with which it can outcross in Canada, there will be no transfer of the novel traits to other species in unmanaged environments. In addition the novel traits were determined to pose minimal risk to non-target organisms.

No changes to agronomic practices typically applied in management of conventional corn are required for corn event 3272. Specifically, no increases in pesticides and fertilizers are required as well as no changes in cultivation, planting, harvesting or volunteer control.

The CFIA has therefore concluded that the potential impact on biodiversity of corn event 3272 is equivalent to that of currently commercialized corn varieties.

V. Criteria for the Livestock Feed Assessment

1. Potential Impact of Corn event 3272 on Livestock Nutrition

Nutritional composition

Replicated trials of corn event 3272 hybrids (A1, B1, B3) and non transgenic control hybrids (A2, B2, B4) were planted at 13 locations in the US in 2003 and 2004 to generate nutritional composition data. Forage and grain samples were analyzed for proximate, ADF, NDF, TDF, amino acids, fatty acids, minerals, vitamins and secondary metabolites (furfural, ferulic acid and p-coumaric acid). Except for ash (grain), no statistically significant differences were observed between event 3272 A1 and control A2 for proximate and fibers in grain and forage. Statistically significant differences were observed between event 3272 B1 and control B2 for protein, carbohydrate, starch, TDF in grain as well as protein and ADF in forage, however all means were within literature values. No statistically significant differences were observed between event 3272 B3 and control B4 grain for crude protein, crude fat and ash. Although ADF, NDF and TDF were statistically significantly lower in transgenic compared to the control. Apart from Mn (grain) and Fe (forage) in one hybrid pair, no statistically significant differences were observed between the transgenic and controls for all minerals. Mean values for Mn and Fe in event 3272 were within literature values. Vitamin B1 was significantly higher in event 3272 B1 compared to control B2, while vitamin B6 in event 3272 (A1and B3) was significantly lower than control (A2 and B4), respectively. All vitamin levels were within the literature values. No statistically significant differences were observed between the transgenic and control hybrids for palmitic, stearic, oleic, linoleic and linolenic acids for both growing seasons. Amino acids in transgenic event 3272, B1(except tyrosine) were statistically significantly higher than control B2, however the means were within literature values. No statistically significant differences were found between event 3272 (A1 and B3) and controls (A2 and B4), respectively, for all amino acids except tryptophan, in which the transgenic was higher than the controls, but was within literature values for commercial corn. No statistically significant differences were observed between transgenic A1, B1 and controls for ferulic acid and p-coumaric acid, however ferulic acid in B3 was statistically significantly lower than the control. All levels of metabolites were within literature values.

Antinutritional factors

Replicated trials of corn event 3272 hybrids (A1, B1, B3) and non transgenic control hybrids (A2, B2, B4) were planted at 13 locations in the US in 2003 and 2004 to generate anti-nutrient data. No statistically significant differences were observed between the transgenic and control pairs for phytic acid, inositol (2 hybrid pairs), raffinose and trypsin inhibitor. All means were within the range of literature values.

The evidence provided by Syngenta Seeds Inc. supports the conclusion that the nutritional composition of corn event 3272 is substantially equivalent to conventional corn varieties.

2. Potential Impact of Corn event 3272 on Livestock and Workers/Bystanders

Corn is not known for the production of endogenous allergens and the transformation event which produced corn event 3272 would not be expected to induce their synthesis.

Amylase enzymes from fungal and bacterial sources have a long history of safe use for starch processing in the food processing industry. Alpha amylases, of varying degrees of amino acid homology with AMY797E, occur widely in nature among prokaryotes and eukaryotes, including many plants and animals.

A single-dose oral toxicity study showed that the AMY797E protein is not toxic to mice at a dose of 1,511 mg AMY797E/kg body weight. Additionally, the AMY797E protein is rapidly degraded under conditions present in the gastrointestinal tract and does not have relevant sequence homology to any known toxins or allergens.

There is a low risk of allergic reaction to AMY797E protein from inhalation exposure (unintended bystander effects). However, this risk is not expected to be greater than the risk from exposure to amylase products currently added to some feeds as enzyme supplements.

PMI proteins are present ubiquitously in nature. They have been found in a variety of plants, animals, and prokaryotes. As such it is likely that both livestock and humans are exposed to PMI proteins on an ongoing basis.

A single-dose oral toxicity study showed that the PMI protein is not toxic to mice at a dose of 3,080 mg PMI/kg body weight. Additionally, the PMI protein is rapidly degraded under conditions present in the gastrointestinal tract, is heat liable and does not have relevant sequence homology to any known toxins or allergens.

Based on the detailed characterization provided (nutritional composition and agronomic data of the modified plant compared to the unmodified comparator) it is unlikely that the modification has had any unintended effects on the modified plant.

The evidence provided by Syngenta Seeds Inc. supports the conclusion that the potential impact on livestock and workers/by-standers of corn event 3272 is equivalent to that of currently commercialized corn lines.

VI. New Information Requirements

If at any time, Syngenta Seeds Canada Inc. becomes aware of any information regarding risk to the environment, including risk to human or animal health, which could result from release of corn event 3272 materials in Canada or elsewhere, Syngenta Seeds Canada Inc. will immediately provide such information to the CFIA. On the basis of such new information, the CFIA will re-evaluate the potential impact of event 3272 on the environment, livestock and human health, and may re-evaluate its decision with respect to the livestock feed use and environmental release authorizations of corn event 3272.

VII. Regulatory Decision

Based on the review of the data and information submitted by Syngenta Seeds Inc., and through comparisons of corn event 3272 with unmodified corn counterparts, the Biotechnology Environmental Release Assessment Unit, CFIA, has concluded that the novel genes and their corresponding traits do not confer to corn event 3272 any characteristic that would result in unintended environmental effects following unconfined release.

Based on the review of submitted data and information by Syngenta Seeds Inc., including comparisons of corn event 3272 with it's unmodified corn counterparts, the Animal Feed Division of the Animal Health Directorate has concluded that the introduced genes and their corresponding traits will not confer to corn event 3272 any characteristic that would raise any concerns regarding the safety or nutritional composition of corn event 3272. Grain corn, its byproducts and corn oil are currently listed in Schedule IV of the Feeds Regulations and are, therefore, approved for use in livestock feeds in Canada. Corn event 3272 has been assessed and found to be as safe as and as nutritious as traditional corn varieties. Corn event 3272 and its products are considered to meet present ingredient definitions and are approved for use as livestock feed ingredients in Canada.

Taking into account these evaluations, unconfined release into the environment and use as livestock feed of corn event 3272 is therefore authorized by the Plant Biosafety Office of the Plant Health and Biosecurity Directorate and the Animal Feed Division of the Animal Health Directorate as of March 11, 2008. Any corn lines derived from event 3272 may also be released into the environment and used as livestock feed, provided no inter-specific crosses are performed, provided the intended uses are similar, provided it is known based on characterization that these plants do not display any additional novel traits and are substantially equivalent to currently grown corn varieties in Canada in terms of their potential environmental impact and livestock feed safety and provided the novel genes are expressed at a level similar to that of the authorized line.

Corn event 3272 is subject to the same phytosanitary import requirements as its unmodified counterpart.

Please refer to Health Canada's Decisions on Novel Foods for a description of the food safety assessment of corn event 3272. The food safety decisions are available at the following Health Canada web site:  http://www.hc-sc.gc.ca/fn-an/gmf-agm/appro/index-eng.php

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