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Decision document DD 2013-98: Determination of the safety of Pioneer Hi-Bred Production Ltd.'s corn (Zea mays L.) event 4114

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Issued: 2013-06

This decision document has been prepared to explain the regulatory decision reached under Directive 94-08 (Dir 94-08) - Assessment Criteria for Determining Environmental Safety of Plants with Novel Traits, its companion biology document BIO1994-11 - The Biology of Zea mays L. (Maize), and Section 2.6 - Guidelines for the Assessment of Novel Feeds: Plant Sources, of Chapter 2 of the RG-1 Regulatory Guidance: Feed Registration Procedures and Labelling Standards.

The Canadian Food Inspection Agency (CFIA), specifically the Plant Biosafety Office of the Plant Health and Biosecurity Directorate, the Plant and Biotechnology Risk Assessment Unit of the Plant Health Science Directorate and the Animal Feed Division of the Animal Health Directorate, has evaluated information submitted by Pioneer Hi-Bred Production Ltd. This information is in regard to the insect resistant and herbicide tolerant corn event 4114. The CFIA has determined that this plant with novel traits (PNT) does not present altered environmental risk nor, as a novel feed, does it present livestock feed safety concerns when compared to corn varieties currently grown and permitted to be used as livestock feed in Canada.

Taking into account these evaluations, unconfined release into the environment and use as livestock feed of corn event 4114 are 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 June 21, 2013. Any corn lines derived from corn event 4114 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 corn varieties that are currently grown and permitted to be used as livestock feed 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.

Additionally, with respect to its unconfined release into the environment, the insect management requirements described in the authorization for corn event 4114 must be applied.

Corn event 4114 is subject to the same phytosanitary import requirements as unmodified corn varieties. Corn event 4114 is required to meet the requirements of other jurisdictions, including but not limited to, the Food and Drugs Act and the Pest Control Products Act.

Please note that the livestock feed and environmental safety assessments of novel feeds and PNT 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.

This bulletin is published by the Canadian Food Inspection Agency. For further information, please contact the Plant Biosafety Office or the Animal Feed Division at:

1-800-442-2342
59 Camelot Drive, Ottawa
Ontario K1A 0Y9

Table of contents

  1. Brief identification of the modified plant
  2. Background information
  3. Description of the novel traits
    1. Development method
    2. Resistance to lepidopteran insects
    3. Resistance to corn rootworms (Diabrotica spp.)
    4. Glufosinate-ammonium herbicide tolerance
    5. Stable integration into the plant genome
  4. Criteria for the environmental assessment
    1. Potential of corn event 4114 to become a weed of agriculture or be invasive of natural habitats
    2. Potential for gene flow from corn event 4114 to sexually compatible plants whose hybrid offspring may become more weedy or more invasive
    3. Altered plant pest potential of corn event 4114
    4. Potential impact of corn event 4114 on non-target organisms
    5. Potential impact of corn event 4114 on biodiversity
    6. Potential for development of insect resistance to corn event 4114
  5. Criteria for the livestock feed assessment
    1. Potential impact of corn event 4114 on livestock nutrition
    2. Potential impact of corn event 4114 on animal health and human safety as it relates to the potential transfer of residues into foods of animal origin, and worker/bystander exposure to the feed
  6. New information requirements
  7. Regulatory decision

I. Brief identification of the modified plant

Designation of the modified plant: Corn event 4114 OECD Unique Identifier DP-ØØ4114-3

Applicant: Pioneer Hi-Bred Production Ltd.

Plant species: Corn (Zea mays L.)

Novel traits: Tolerance to glufosinate-ammonium herbicide; resistance to coleopteran pests including Diabrotica virgifera virgifera (western corn rootworm) and Diabrotica longicornis barberi (northern corn rootworm); resistance to lepidopteran pests including Ostrinia nubilalis (European corn borer).

Trait introduction method: Agrobacterium-mediated transformation

Intended use of the modified plant: Corn event 4114 is intended to be grown for traditional corn human food and livestock feed uses. Corn event 4114 is not intended to be grown outside the normal production area for corn in Canada.

II. Background information

Pioneer Hi-Bred Production Ltd. has developed a corn event that is resistant to the European corn borer (Ostrinia nubilalis) and to corn rootworms (Diabrotica virgifera virgifera and Diabrotica barberi), and tolerant to the glufosinate-ammonium herbicide.

Corn event 4114 was developed by Pioneer Hi-Bred Production Ltd. using recombinant-deoxyribonucleic acid (r-DNA) technology, resulting in the introduction of the cry1F gene, the cry34Ab1 and cry35Ab1 genes, and the phosphinothricin acetyltransferase (pat) gene. The cry1F gene is derived from the bacterium Bacillus thuringiensis (B. thuringiensis) subsp. aizawa and encodes the Cry1F insecticidal protein, which confers resistance to the European corn borer. The cry34Ab1 and cry35Ab1 genes are derived from B. thuringiensis strain PS149B1 and encode the Cry34Ab1 and Cry35Ab1 proteins respectively, which together comprise a binary insecticidal protein that confers resistance to the western and northern corn rootworms. The pat gene is derived from the soil bacterium Streptomyces viridochromogenes (S. viridochromogenes) and encodes a phosphinothricin acetyltransferase (PAT) enzyme. This enzyme inactivates the herbicide glufosinate-ammonium.

The traits of resistance to European corn borer and tolerance to glufosinate-ammonium herbicide present in corn event 4114 are also present in the previously-authorized corn event 1507 (see DD2002-41). Additionally, the traits of resistance to corn rootworms and tolerance to glufosinate-ammonium herbicide present in corn event 4114 are also present in the previously authorized corn event 59122 (see DD2005-55). The combination of these traits is also present in the stack of corn event 1507 and corn event 59122 (1507 × 59122), which was developed through conventional breeding of corn event 1507 and corn event 59122, and which was authorized by the CFIA in 2006. Thus, commercial corn hybrids containing the same traits as present in corn event 4114 have been grown in Canada since 2007.

Pioneer Hi-Bred Production Ltd. has provided information on the identity of corn event 4114, a detailed description of the transformation method, and information 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. Information 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 4114 was field-tested at 15 sites in the United States (US) and at 2 sites in Canada in 2010. The locations of these trials share similar environmental and agronomic conditions to corn production areas in Canada and were considered representative of major Canadian corn growing regions.

Agronomic characteristics of corn event 4114, including seedling vigour, early stand count, days to 50% pollen shed, days to 50% silking, stay green, ear height, plant height, dropped ears, stalk lodge plants, root lodge plants, final stand count and susceptibility to various corn pests and pathogens, were compared to those of an unmodified control corn variety, which shares the same genetic background as corn event 4114 but had not been modified.

Nutritional components of corn event 4114 grain and forage, such as proximate, amino acids, fatty acids, minerals, vitamins, anti-nutrients and secondary metabolites were compared with those of the unmodified control corn variety and other conventional control corn varieties.

The Plant and Biotechnology Risk Assessment (PBRA) Unit of the Plant Health Science Directorate, CFIA, has reviewed the above information, in light of the assessment criteria for determining environmental safety of PNT, as described in Directive 94-08 (Dir 94-08) - Assessment Criteria for Determining Environmental Safety of Plants with Novel Traits". The PBRA Unit has considered:

The Animal Feed Division (AFD) of the 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 Section 2.6 Guidelines for the Assessment of Novel Feeds: Plant Sources, of Chapter 2 of the RG-1 Regulatory Guidance: Feed Registration Procedures and Labelling Standards.

The AFD has considered both intended and unintended effects and similarities and differences between corn event 4114 and unmodified corn varieties relative to the safety and efficacy of feed ingredients derived from corn event 4114 for their intended purpose, including:

The AFD has also considered whether feeds derived from corn event 4114 meet feed definitions and requirements of feeds as listed in Schedule IV of the Feeds Regulations.

Pioneer Hi-Bred Production Ltd. has provided the CFIA with a method for the detection and identification of corn event 4114.

III. Description of the novel traits

1. Development method

Corn event 4114 was developed through Agrobacterium-mediated transformation of corn embryos, and contains the cry1F, cry34Ab1, cry35Ab1, and pat genes, and their associated regulatory elements. Transformed cells were selected on the basis of tolerance to glufosinate-ammonium and regenerated to produce plants. Corn event 4114 was identified as a successful transformant based on molecular analyses, insect and herbicide efficacy, and agronomic evaluations, and was thus chosen for further development.

2. Resistance to lepidopteran insects

Bacillus thuringiensis is a common gram-positive soil-borne bacterium. In its spore-forming stage, it produces several insecticidal crystal proteins (ICPs), also known as Cry endotoxins, which are active against certain insect groups. Foliar insecticides based on ICP (generally known as B.t.) have been registered for over 50 years in Canada and have a long history of safe use. The Cry1F protein expressed by B. thuringiensis  subsp. aizawai is insecticidal to some lepidopteran species. The Cry1F protein is cleaved in the insect's gut to a bio-active, trypsin-resistant core. Insecticidal activity is believed to depend on the binding of the bio-active fragment to specific receptors present in susceptible insects on midgut epithelial cells, forming pores that disrupt osmotic balance and eventually result in cell lysis and insect death.

A synthetic cry1F gene was developed to maximize its expression in corn event 4114. It encodes a protein with a high degree of similarity to the Cry1F protein of B. thuringiensis  subsp. aizawai. The amino acid sequence of the Cry1F protein expressed in corn event 4114 is identical to that of the Cry1F protein expressed in corn event 1507, which has been subject to a previous CFIA safety assessment (DD2002-41).

The Cry1F protein expression in corn event 4114 is driven by a constitutive promoter. Samples of corn tissues were collected from plants grown in 5 field trials in the US and Canada. The average Cry1F protein expression in μg/g dry weight tissue (dwt), as evaluated by enzyme-linked immunosorbent assay (ELISA), was as follows: 2.0-13.0 μg/g dwt in leaves across growth stages, 3.8-5.5 μg/g dwt in roots across growth stages, 35 μg/g dwt in pollen, 7.8 μg/g dwt in forage and 3.3 μg/g dwt in grain.

The potential allergenicity and toxicity of the Cry1F protein to livestock and non-target organisms were evaluated. The weight of evidence indicates that the Cry1F protein is unlikely to be allergenic. The source of the cry1F gene, B. thuringiensis  subsp. aizawai, is not known to produce allergens; the Cry1F protein amino acid sequence lacks relevant similarities to known allergens; and microbial Cry1F protein was shown experimentally to be rapidly degraded in simulated gastric fluid and not to be heat stable. It was also concluded that the Cry1F protein is unlikely to be toxic to livestock or non-target organisms because it lacks a mode of action to suggest that it is intrinsically toxic to livestock or non-target organisms, because the Cry1F protein amino acid sequence lacks relevant similarities to known toxins that are toxic to mammals, and because no adverse effects were observed when microbial Cry1F protein was ingested by mice at doses of approximately 576 milligrams protein per kilogram body weight (mg/kg bwt). For a more detailed discussion of the potential allergenicity and toxicity of the Cry1F protein, see Section V, part 2.

3. Resistance to corn rootworms (Diabrotica spp.)

Bacillus thuringiensis strain PS149B1 produces a binary ICP that consists of 2 proteins, Cry34Ab1 and Cry35Ab1, with respective molecular weights of approximately 14 kilodaltons (kDa) and 44 kDa. This binary Cry34/35Ab1 ICP has been shown to be selectively toxic to certain coleopteran species, including the western and northern corn rootworms. Similar to other B. thuringiensis ICP, insecticidal activity of the Cry34/35Ab1 ICP is believed to depend on the binding of the ICP to specific receptors present in susceptible insects on midgut epithelial cells, forming pores that disrupt osmotic balance and eventually resulting in cell lysis and insect death. The Cry34Ab1 protein is active alone, but it is substantially synergised by the Cry35Ab1 protein.

Synthetic cry34Ab1 and cry35Ab1 genes were developed to maximize their expression in corn. The amino acid sequences of the Cry34Ab1 and Cry35Ab1 proteins expressed in corn line 4114 are identical to those of the corresponding proteins expressed in corn event 59122, which has been subject to a previous CFIA safety assessment (DD2005-55).

The Cry34Ab1 protein expression in corn event 4114 is driven by a constitutive promoter. Samples of corn tissues were collected from plants grown in 5 field trials in the US and Canada. The average Cry34Ab1 protein expression in μg/g dwt, as evaluated by enzyme-linked immunosorbent assay (ELISA), was as follows: 21-110 μg/g dwt in leaves across growth stages, 17-23 μg/g dwt in roots across growth stages, 9.2 μg/g dwt in pollen, 52 μg/g dwt in forage and 24 μg/g dwt in grain.

The Cry35Ab1 protein expression in corn event 4114 is driven by a constitutive promoter. Samples of corn tissues were collected from plants grown in 5 field trials in the US and Canada. The average Cry35Ab1 protein expression in μg/g dwt, as evaluated by enzyme-linked immunosorbent assay (ELISA), was as follows: 27-90 μg/g dwt in leaves across growth stages, 6.4-13 μg/g dwt in roots across growth stages, 0.34 μg/g dwt in pollen, 29 μg/g dwt in forage and 1.1 μg/g dwt in grain.

The potential allergenicity and toxicity of the Cry34Ab1 and Cry35Ab1 proteins to livestock and non-target organisms was evaluated. The weight of evidence indicates that the Cry34Ab1 and Cry35Ab1 proteins are unlikely to be allergenic. The source of the cry34Ab1 and cry35Ab1 genes, B. thuringiensis strain PS149B1, is not known to produce allergens; the Cry34Ab1 and Cry35Ab1 amino acid sequences lack relevant similarities to known allergens, and microbial Cry34Ab1 and Cry35Ab1 proteins were shown experimentally to be rapidly degraded in simulated gastric fluid and not to be heat stable. It was also concluded that the Cry34Ab1 and Cry35Ab1 proteins are unlikely to be toxic to livestock or non-target organisms because they lack a mode of action to suggest that they are intrinsically toxic to livestock or non-target organisms, because the Cry34Ab1 and Cry35Ab1 amino acid sequences lack relevant similarities to known toxins that are toxic to mammals and because no adverse effects were observed when microbial Cry34Ab1 and Cry35Ab1 proteins were ingested by mice at doses of approximately 2700 and 1850 mg/kg bwt, respectively. For a more detailed discussion of the potential allergenicity and toxicity of the Cry34Ab1 and Cry35Ab1 proteins, see Section V, part 2.

4. Glufosinate-ammonium herbicide tolerance

Glufosinate-ammonium herbicide inhibits the activity of the plant enzyme glutamine synthetase by competitively binding in place of the normal substrate, glutamate (glutamic acid). This prevents the synthesis of L-glutamine, which is not only an important chemical precursor for the synthesis of nucleic acids and proteins, but serves as the mechanism of ammonia incorporation for plants. The application of glufosinate-ammonium causes accumulation of ammonia and cessation of photosynthesis, resulting in plant death. Corn event 4114 was developed to be tolerant to the herbicide glufosinate-ammonium by incorporation of the pat gene. The pat gene encodes the PAT enzyme, which acetylates the primary amino group of glufosinate-ammonium, rendering it inactive. Introduction of the pat gene into corn event 4114 confers commercial-level tolerance to the herbicide glufosinate-ammonium.

The pat gene was derived from S. viridochromogenes, a gram-positive soil bacterium. A synthetic pat gene was developed to maximize its expression in corn. The amino-acid sequence of the PAT protein produced in corn event 4114 is the same as that of the PAT protein produced in other glufosinate-ammonium-tolerant crops that have been subject to a previous CFIA safety assessment, including corn event 1507 (DD2002-41) and corn event 59122 (DD2005-55).

The PAT protein expression in corn event 4114 is driven by a constitutive promoter. Samples of corn tissues were collected from plants grown in 5 field trials in the US and Canada. The average PAT protein expression in μg/g dwt, as evaluated by enzyme-linked immunosorbent assay (ELISA), was as follows: 0.52 -14 μg/g dwt in leaves across growth stages, 0.13 -0.65 μg/g dwt in roots across growth stages, 1.9 μg/g dwt in forage and below the limits of detection in grain and pollen.

The potential allergenicity and toxicity of the PAT protein to livestock and non-target organisms was evaluated. The weight of evidence indicates that the PAT protein is unlikely to be allergenic. The source of the pat gene, S. viridochromogenes, is not known to produce allergens; the PAT protein amino acid sequence lacks relevant similarities to known allergens, and microbial PAT protein was shown experimentally to be rapidly degraded in simulated gastric fluid. It was also concluded that the PAT protein was unlikely to be toxic to livestock or non-target organisms because it lacks a mode of action to suggest that it is intrinsically toxic to livestock and non-target organisms, because the PAT protein amino acid sequence lacks relevant similarities to known toxins and because no adverse effects were observed when microbial PAT protein was ingested by mice at doses of approximately 5000 mg/kg bwt. For a more detailed discussion of the potential allergenicity and toxicity of the PAT protein, see Section V, part 2.

5. Stable integration into the plant genome

Molecular characterization by Southern blot analysis and nucleotide sequencing demonstrated that corn event 4114 contains one intact copy of each of the cry1F, cry34Ab1, cry35Ab1 and pat gene cassettes inserted at a single site in the corn genome. No additional elements, including intact or partial DNA fragments of the 4 gene cassettes or backbone sequences from the plasmid vector, linked or unlinked to the intact insert, were detected in corn event 4114.

The stability of the insert within corn event 4114 was verified by Southern blot analysis over 4 generations. The inheritance pattern of the insert and the glufosinate tolerance trait across 5 segregating generations of corn event 4114 showed that the insert segregates according to Mendelian rules of inheritance for a single genetic locus.

IV. Criteria for the environmental assessment

1. Potential of corn event 4114 to become a weed of agriculture or be invasive of natural habitats

The biology of corn, described in the CFIA biology document BIO1994-11 - The Biology of Zea mays L. (Maize), states 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 Pioneer Hi-Bred Production Ltd., corn event 4114 was determined not to be significantly different from unmodified corn varieties in this respect.

The CFIA evaluated data submitted by Pioneer Hi-Bred Production Ltd. on the reproductive biology and life history traits of corn event 4114. This event was field-tested in 2010 at 15 locations in the US and 2 locations in Canada. The US locations share similar environmental and agronomic conditions to Southern Ontario and Quebec and were considered to be representative of major Canadian corn growing regions. During the field trials, corn event 4114 was compared to the unmodified control corn variety. Phenotypic and agronomic traits were evaluated, covering a broad range of characteristics that encompass the entire life cycle of the corn plant. The traits included early population, seedling vigour, plant height, ear height, stalk lodging, root lodging, final population, stay green, time to 50% silking, time to 50% pollen shed and yield. There were no statistically significant differences detected in any of the phenotypic and agronomic traits between corn event 4114 and the unmodified control corn variety.

Pioneer Hi-Bred Production Ltd. evaluated the germination of corn event 4114 seed under 3 temperature regimes. No statistically significant differences were detected between corn event 4114 and the unmodified control corn variety with respect to the percentage of germinated seed for any of the temperature regimes. No potentially dormant seeds were identified using a standard tetrazolium chloride test, which was applied to any non-germinated seed classified as hard or imbibed. Therefore, the introduction of the novel traits did not impact the germination of the corn seed and did not confer dormancy to the corn seed.

The susceptibility of corn event 4114 to various corn pests and pathogens was evaluated at multiple locations in the US and Canada between 2007 and 2010 (further detail provided below in Section 3: Altered Plant Pest Potential of Corn Event 4114). No trend in increased or decreased susceptibility to pests or pathogens was observed in corn event 4114 compared to conventional control corn varieties, with the exception of the intended resistance to the European corn borer and corn rootworms.

No competitive advantage was conferred to plants of corn event 4114, other than that conferred by tolerance to the glufosinate-ammonium herbicide and resistance to some pest insects, as the reproductive characteristics, growth characteristics and tolerance to biotic stresses of corn event 4114 were comparable to those of the unmodified control corn variety. Tolerance to the glufosinate-ammonium herbicide provides a competitive advantage only when this herbicide is used, and will not, in and of itself, make a glufosinate-ammonium herbicide tolerant plant weedier or more invasive of natural habitats. Corn event 4114 plants growing as volunteers will not be controlled if glufosinate-ammonium herbicide is used as the only weed control tool. However, control of corn event 4114 as a volunteer weed in subsequent crops or in fallow ground can be achieved by the use of other classes of herbicides, or by mechanical means. As feeding damage by pest insects is not known to be a major factor restricting the establishment or distribution of corn in Canada, the introduction of the insect resistance traits will not make corn event 4114 weedy or invasive of natural habitats.

The novel traits have no intended or observed effects on weediness or invasiveness. The CFIA has therefore concluded that corn event 4114 has no altered weediness or invasiveness potential in Canada compared to currently grown corn varieties.

The CFIA considers the changes in usual agronomic practices that may arise from volunteer plants with novel herbicide tolerances. Similarly, the CFIA considers the potential that continued application of the same herbicide in subsequent rotations may lead to increased selection pressure for herbicide resistant weed populations. In order to address these issues, an herbicide stewardship plan that includes integrated weed management strategies should be implemented. These plans may include a recommendation to rotate or combine weed control products with alternate modes of action and to employ other weed control practices.

Pioneer Hi-Bred Production Ltd. has submitted an herbicide tolerance management plan, which was determined to be satisfactory when evaluated by the PBRA Unit.

Pioneer Hi-Bred Production Ltd. will make this management plan readily available to growers and agriculture extension personnel, in both private and public sectors, to promote careful management practices for corn event 4114. Pioneer Hi-Bred Production Ltd. will provide an efficient mechanism for growers to report agronomic problems to the company, which will facilitate the ongoing monitoring of corn event 4114. Pioneer Hi-Bred Production Ltd. will monitor grower implementation to determine the effectiveness of the management plan and make any changes to the plan as appropriate.

2. Potential for gene flow from corn event 4114 to sexually compatible plants whose hybrid offspring may become more weedy or more invasive

The biology of corn, as described in the CFIA biology document BIO1994-11 - The Biology of Zea mays L. (Maize), indicates that there are no sexually compatible plants in Canada that can hybridize with corn. The novel traits introduced into corn event 4114 (resistance to the European corn borer and corn rootworms, and tolerance to the glufosinate-ammonium herbicide) are unrelated to sexual compatibility.

The CFIA has therefore concluded that gene flow from corn event 4114 to wild relatives is not possible in Canada.

3. Altered plant pest potential of corn event 4114

Corn is not considered a plant pest in Canada. The novel traits introduced in corn event 4114 (resistance to the European corn borer and corn rootworms, and tolerance to the glufosinate-ammonium herbicide) are unrelated to plant pest potential (i.e., the potential for the plant to harbour new or increased populations of pathogens or pests).

The susceptibility of corn event 4114 to various corn pests and pathogens was evaluated in the field at 31 sites in the US from 2007 to 2010 and 2 sites in Canada from 2008 to 2010. The stressors observed included European corn borer, corn rootworms, Japanese beetle, bean leaf beetle, grasshopper, aphids, fall armyworm, lady beetle, stink bugs, western bean cutworm, slugs, gray leaf spot, Stewart's wilt, northern corn leaf blight, common corn rust, anthracnose, crazy top, gibberella stalk rot, corn eyespot and diplodia ear rot. With the exception of the intended resistance to the European corn borer and corn rootworms, the evaluations of corn event 4114 did not show any increased or decreased susceptibility to these corn pests or pathogens compared to the unmodified control corn variety and/or conventional control corn varieties grown at the same locations.

The CFIA has therefore concluded that corn event 4114 does not display any altered plant pest potential compared to currently grown corn varieties.

4. Potential impact of corn event 4114 on non-target organisms

The glufosinate-ammonium herbicide tolerance trait introduced into corn event 4114 is unrelated to a potential impact on non-target organisms. The PAT protein produced in corn event 4114, which confers tolerance to the glufosinate-ammonium herbicide, is the same as the PAT protein produced in corn events 1507 and 59122. These corn events have been subject to previous CFIA safety assessments (DD2002-41 and DD2005-55). Detailed characterization of the PAT protein expressed in corn event 1507 and 59122 led to the conclusion that this protein does not display any characteristic of a potential toxin or allergen (Section V, part 2). In addition, the PAT protein in corn events 1507 and 59122 has a history of environmental safety. Therefore, no negative impacts resulting from exposure of organisms to the PAT protein expressed in corn event 4114 are expected.

The history of use and available literature indicate that ICP derived from B. thuringiensis are active against only specific insect groups and are not toxic to other organisms, including human beings.

The Cry1F protein produced in corn event 4114 is active only against certain lepidopteran insects. The Cry1F protein in corn event 4114 is identical to the Cry1F protein in corn event 1507, which has been subject to a previous safety assessment for non-target organisms (DD2002-41). Thus, dietary toxicity studies on non-target organisms submitted in support of the environmental safety of the Cry1F protein in corn event 1507 were used to evaluate the potential impact on non-target organisms of the Cry1F protein in corn event 4114. These studies showed that the Cry1F protein has no negative effect on honeybees, green lacewing larvae, ladybird beetles, daphnia, collembola, parasitic hymenoptera, earthworm, bobwhite quail or mice when ingested at doses greatly exceeding the anticipated levels of exposure to the Cry1F protein produced in corn event 4114 tissues. It was also demonstrated that the Cry1F protein exhibits virtually no toxicity to larvae of the monarch butterfly at levels greatly exceeding the anticipated levels of exposure.

Similarly, the Cry34Ab1 and Cry35Ab1 proteins produced in corn event 4114 are active only against certain coleopteran insects. The Cry34Ab1 and Cry35Ab1 proteins in corn event 4114 are identical to the corresponding proteins in corn event 59122, which has been subject to a previous CFIA safety assessment (DD2005-55). Thus, data from dietary toxicity studies on non-target organisms submitted in support of environmental safety of the Cry34Ab1 and Cry35Ab1 proteins in corn event 59122 were used to evaluate the potential impact on non-target organisms of the Cry34Ab1 and Cry35Ab1 proteins in corn event 4114. These studies showed that the Cry34Ab1 and Cry35Ab1 proteins have no negative effect on honeybee larvae, green lacewing larvae, ladybird beetles, parasitic wasp, ground beetle, daphnia, collembola, earthworm, mice or the rainbow trout when ingested at doses greatly exceeding the anticipated levels of exposure to the Cry34Ab1 and Cry35Ab1 proteins produced in corn event 4114 tissues.

Therefore, no negative impacts resulting from exposure of non-target organisms to the Cry1F, Cry34Ab1, Cry35Ab1 and PAT proteins produced in corn event 4114 are anticipated.

Field evaluations of corn event 4114 did not show any increased resistance to insect pests other than the European corn borer and corn rootworms, or to pathogens, compared to the conventional control corn varieties (see Section 3. Altered Plant Pest Potential of Corn Event 4114).

Composition analyses showed that the levels of key nutrients and anti-nutrients in grain and forage from corn event 4114 are comparable to those in conventional corn varieties (See Section V, part 1. Potential Impact of Corn Event 4114 on Livestock Nutrition). Therefore, it is very unlikely that the introduction of the novel traits may have caused unintended changes to the composition of corn event 4114 tissues that would negatively impact organisms interacting with corn event 4114.

Collectively, these information elements indicate that the interactions between corn event 4114 and the non-target populations of animals and microorganisms interacting with corn crops will be similar in comparison to currently grown corn varieties.

The CFIA has therefore determined that the unconfined release of corn event 4114 in Canada will not result in altered impacts on non-target organisms, including humans, compared to currently grown corn varieties.

5. Potential impact of corn event 4114 on biodiversity

Corn event 4114 expresses no novel phenotypic characteristics that would extend its range beyond the current geographic range of corn production in Canada. 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. Corn event 4114 is unlikely to cause adverse effects on non-target organisms and does not display increased weediness, invasiveness or plant pest potential. It is therefore unlikely that corn event 4114 will have any direct effects on biodiversity, in comparison to the effects that would be expected from the cultivation of the corn varieties that are currently grown in Canada.

At present, crop rotation, the use of corn rootworm resistant corn varieties and chemical insecticide treatments are common practices to control corn rootworms in Canada. The use of corn varieties resistant to the European corn borer and chemical treatments on sweet corn crops are a common practice to control the European corn borer in Canada. Therefore, the reduction in local corn rootworm populations and European corn borer populations as a result of the release of corn event 4114 does not present a significant change from existing agricultural practices.

Corn event 4114 has tolerance to the broad spectrum herbicide glufosinate-ammonium. The use of this herbicide in cropping systems has the intended effect of reducing local weed populations within agro-ecosystems. This may result in a reduction in local weed species biodiversity, and may have effects on other trophic levels that utilize these weed species. However, it must be noted that the goal of reduction in weed biodiversity in agricultural fields is not unique to the use of PNT, corn event 4114, or the cultivation of corn.

It is therefore unlikely that corn event 4114 will have any indirect effects on biodiversity, in comparison to the effects that would be expected from cultivation of currently grown corn varieties.

The CFIA has concluded that the introduced genes and their corresponding novel traits do not confer to corn event 4114 any characteristic that would result in unintended environmental effects following unconfined release. The CFIA has therefore concluded that the potential impact on biodiversity of corn event 4114 is unlikely to be different from that of the corn varieties that are currently grown in Canada.

6. Potential for development of insect resistance to corn event 4114

In order to minimize the likelihood of the development of insect pest resistance to PNT expressing novel insect resistance, the CFIA requires that an insect resistance management (IRM) plan be implemented for these products. Coleopteran and lepidopteran insects have a significant ability to develop resistance to conventional chemical insecticides. Therefore, it is reasonable to expect that resistance to the insecticidal proteins expressed in corn event 4114 may develop. The following IRM design is intended to reduce or delay corn rootworm (CRW) resistance to the Cry34Ab1 and Cry35Ab1 proteins and European corn borer (ECB) resistance to the Cry1F protein. A component of the IRM strategy that will be used with corn event 4114 is the establishment of a refuge of CRW/ECB-susceptible corn within or adjacent to the corn event 4114 field. Should resistant insects occur, they would then be able to mate with susceptible insects to keep the frequency of resistance genes diluted in the insect population.

The CFIA believes that sound management practices and IRM strategies can significantly reduce and delay the development of Cry34Ab1 and Cry35Ab1 resistant CRW populations and Cry1F resistant ECB populations. However, the CRW and ECB populations must be monitored for the development of resistance in a regular and consistent manner.

The CFIA understands that Pioneer Hi-Bred Production Ltd. has developed, and will implement, an IRM plan that includes the following key components:

  1. The use of a refuge to provide populations of ECB that have not been exposed to the Cry1F protein, and populations of CRW that have not been exposed to the Cry34Ab1/Cry35Ab1 proteins, and are available to reproduce with potentially resistant individuals that may emerge from corn event 4114 crops.
  2. The early detection of CRW and ECB populations resistant to the corn-expressed insecticidal proteins is extremely important. Close monitoring for the presence of such populations, in CRW-resistant and ECB-resistant corn fields and surrounding areas, is therefore warranted. Monitoring includes the development of appropriate detection tools such as visual field observations and laboratory bioassays, education of growers, reporting schedules, and mitigation procedures in case of resistance development.
  3. Education tools will be developed and provided to all growers, district managers and field managers. These will include information on product performance, resistance management, monitoring procedures and timetables, detection protocols for resistant CRW and ECB individuals, instructions to contact Pioneer Hi-Bred Production Ltd. and strategies to be followed if unexpected levels of CRW and/or ECB damage occur.
  4. Pioneer Hi-Bred Production Ltd. will have documented procedures in place for responding to these reported instances of unexpected CRW and/or ECB damage. These procedures will include, where warranted, the collection of plant tissues and CRW and ECB individuals and use of appropriate bioassays to evaluate suspected Cry34Ab1, Cry35Ab1 and Cry1F resistant individuals, and a protocol for immediate action to control resistant individuals.
  5. Detection of confirmed resistant CRW and/or ECB populations and mitigation measures will be immediately reported to CFIA.
  6. Integrated Pest Management practices will be promoted, such as prediction of infestation problems from field histories, as well as crop and trait rotation.

Note: The Plant Biosafety Office may periodically verify compliance with the IRM requirements.

V. Criteria for the livestock feed assessment

The AFD considered nutrient and anti-nutrient profiles; the safety of feed ingredients derived from corn event 4114, including the presence of gene products, residues, and metabolites in terms of animal health and human safety as it relates to the potential transfer of residues into foods of animal origin and worker/bystander exposure to the feed; and whether feeds derived from corn event 4114 meet the definitions and requirements of feeds as listed in Schedule IV of the Feeds Regulations.

1. Potential impact of corn event 4114 on livestock nutrition

Nutrient and anti-nutrient composition

The nutritional equivalence of corn event 4114 to the unmodified control corn variety was determined from 6 replicated field trials in the US and in Canada in 2010. Seeds were planted in a randomized complete design with 4 plots each of corn event 4114 and the unmodified control corn variety at each site. Compositional analysis was performed on forage and grain samples collected from each plot. Forage and grain samples were analysed for proximate (crude fat, ash, protein and moisture), acid detergent fibre (ADF), neutral detergent fibre (NDF), calcium, and phosphorus. Grain samples were further analysed for amino acids, fatty acids, vitamins, minerals, secondary metabolites (ferulic acid, p-coumaric acid, and furfural) and anti-nutrients (phytic acid, trypsin inhibitor, inositol, and raffinose) as recommended by the Organisation for Economic Co-operation and Development (OECD) consensus document for new varieties of corn (OECD, 2002 - PDF (209 kb)). Composition data were analysed statistically using a mixed model analysis of variance, and the significance of any differences observed between corn event 4114 and the unmodified control corn variety was evaluated (P>0.05). The biological relevance of any significant difference between corn event 4114 and the unmodified control corn variety was assessed within the range of the values obtained from conventional control corn varieties grown in 2 separate trials and in the published scientific literature (Agriculture and Food Systems Institute (AFSI), 2010, OECD, 2002).

There were no statistically significant differences between the unmodified control corn variety and corn event 4114 forage for crude fat, ash, protein, ADF, NDF, calcium, and phosphorous levels. Comparison of proximate and fibre levels in grain samples from corn event 4114 and the unmodified control corn variety resulted in no statistically significant differences for crude fat, crude protein, carbohydrates, ADF, NDF, or crude fibre. Ash content in corn event 4114 grain was statistically significantly higher than in the unmodified control corn variety; however the mean value in corn event 4114 was within the range of the values observed in the conventional control corn varieties and the published scientific literature (AFSI, 2010, OECD, 2002). Although statistically significant differences were noted for phosphorus and potassium between grain from corn event 4114 and grain from the unmodified control corn variety, the mean values were within the range of the values observed in the conventional control corn varieties and the published scientific literature (AFSI, 2010, OECD, 2002). There were no statistically significant differences in the concentration of β-carotene, thiamine, niacin, pantothenic acid, pyridoxine, folic acid, α-tocopherol, γ-tocopherol or total tocopherol in grain between corn event 4114 and the unmodified control corn variety. No statistically significant differences were observed between corn event 4114 and the unmodified control corn variety for amino acids measured in grain. A statistically significant difference was observed between corn event 4114 and the unmodified control corn variety for the level of eicosenoic acid in grain; however, the mean value in corn event 4114 was within the range of values observed in the conventional control corn varieties and the published scientific literature (AFSI, 2010, OECD, 2002). There were no statistically significant differences in mean concentrations of ferulic and p-coumaric acid in grain between corn event 4114 and the unmodified control corn variety. The metabolite furfural was below the lower limit of quantification in grain from both corn event 4114 and the unmodified control corn variety. There were no statistically significant differences between the mean concentrations of inositol, phytic acid, raffinose and trypsin inhibitor in grain from corn event 4114 and the unmodified control corn variety. All means were within the range of values observed in the conventional control corn varieties and in published scientific literature (AFSI, 2010, OECD, 2002).

Conclusion

It was concluded based on the evidence provided by Pioneer Hi-Bred Production Ltd. that the nutritional composition of corn event 4114 is similar to that of the conventional control corn varieties and to that reported for other corn varieties in the published scientific literature.

2. Potential impact of corn event 4114 on animal health and human safety as it relates to the potential transfer of residues into foods of animal origin, and worker/bystander exposure to the feed

Corn event 4114 is tolerant to the herbicide glufosinate-ammonium and resistant to the European corn borer and corn rootworms due to the production of the PAT, Cry1F, Cry34Ab1 and Cry35Ab1 proteins.

The assessment of corn event 4114 evaluated the impact of the following potential hazards relative to the safety of feed ingredients derived from this event:

Novel Cry1F protein

To obtain sufficient quantities of Cry1F protein for evaluation of environmental and feed safety, it was necessary to express the cry1F gene in a microbial production system. Equivalency was demonstrated between corn event 4114-produced Cry1F protein and a microbial-produced Cry1F protein that had been used in studies previously submitted for Pioneer Hi-Bred Production Ltd.'s corn event 1507 (DD2002-41), based on the same amino acid sequence and similar molecular weights and immunoreactivities.

Demonstration of equivalence between the Cry1F protein produced in corn event 4114 and the microbially-produced Cry1F protein used in studies submitted for corn event 1507 allows utilization of information from these studies to confirm the safety of the Cry1F protein produced in corn event 4114.

The potential allergenicity and toxicity of the Cry1F protein was evaluated.

With respect to potential allergenicity, it is recognized that no single experimental method yields decisive evidence for allergenicity, thus a weight-of-evidence approach was taken, taking into account information obtained with various test methods. The source of the cry1F gene, B. thuringiensis  subsp. aizawai, is not known to produce allergens and a bioinformatics evaluation of the Cry1F amino acid sequence confirmed the lack of relevant similarities between the Cry1F protein and known allergens. Unlike many allergens, microbial Cry1F safety studies previously provided for corn event 1507 indicated that the Cry1F protein is readily degraded in simulated mammalian gastric fluid. The weight of evidence thus indicates that the Cry1F protein is unlikely to be allergenic.

In terms of its potential toxicity, the Cry1F protein lacks a mode of action to suggest that it is intrinsically toxic to livestock, and a bioinformatics evaluation of the Cry1F protein's amino acid sequence confirmed the lack of relevant similarities to known toxins that are toxic to mammals. In addition, microbial protein safety studies previously provided for corn event 1507 indicated that no adverse effects were observed when the Cry1F protein was ingested by mice at approximately 576 mg/kg bwt. This information indicates that the Cry1F protein is unlikely to be toxic to livestock.

The livestock exposure to the Cry1F protein is expected to be negligible as the protein is expressed at very low levels in corn event 4114, is rapidly degraded under conditions that simulate the mammalian digestive tract, and is unstable under heating conditions expected to be encountered during processing of some corn products.

Novel Cry34Ab1 and Cry35Ab1 proteins

To obtain sufficient quantities of Cry34Ab1 and Cry35Ab1 proteins for evaluation of environmental and feed safety, it was necessary to express the cry34Ab1 and cry35Ab1 genes in a microbial production system. Equivalency was demonstrated between corn event 4114-produced Cry34Ab1 and Cry35Ab1 proteins and microbial-produced Cry34Ab1 and Cry35Ab1 proteins that had been used in studies previously submitted for Pioneer Hi-Bred Production Ltd.'s corn event 59122 (DD2005-55), based on the same amino acid sequence and similar molecular weights and immunoreactivities.

Demonstration of equivalence between Cry34Ab1 and Cry35Ab1 proteins produced in corn event 4114 and the microbially-produced Cry34Ab1 and Cry35Ab1 proteins used in studies submitted for corn event 59122 allows utilization of information from these studies to confirm the safety of the Cry34Ab1 and Cry35Ab1 proteins produced in corn event 4114.

The potential allergenicity and toxicity of the Cry34Ab1 and Cry35Ab1 proteins was evaluated. With respect to potential allergenicity, it is recognized that no single experimental method yields decisive evidence for allergenicity, thus a weight-of-evidence approach was taken, taking into account information obtained with various test methods. The source of the cry34Ab1 and cry35Ab1 genes, B. thuringiensis strain PS149B1, is not known to produce allergens and a bioinformatics evaluation of the Cry34Ab1 and Cry35Ab1 amino acid sequences confirmed the lack of relevant similarities between the Cry34Ab1 and Cry35Ab1 proteins and known allergens. Unlike many allergens, microbial Cry34Ab1 and Cry35Ab1 safety studies previously provided for corn event 59122 indicated that the Cry34Ab1 and Cry35Ab1 proteins are readily degraded in simulated mammalian gastric fluid. The weight of evidence thus indicates that the Cry34Ab1 and Cry35Ab1 proteins are unlikely to be allergenic.

In terms of their potential toxicity, the Cry34Ab1 and Cry35Ab1 proteins lack a mode of action to suggest that they are intrinsically toxic to livestock, and a bioinformatics evaluation of the Cry34Ab1 and Cry35Ab1 amino acid sequences confirmed the lack of relevant similarities to known toxins that are toxic to mammals. In addition, microbial protein safety studies previously provided for corn event 59122 indicated that no adverse effects were observed when the Cry34Ab1 and Cry35Ab1 proteins were ingested by mice at approximately 2700 and 1850 mg/kg bwt, respectively. This information indicates that the Cry34Ab1 and Cry35Ab1 proteins are unlikely to be toxic to livestock.

The livestock exposure to the Cry34Ab1 and Cry35Ab1 proteins is expected to be negligible as the proteins are expressed at very low levels in corn event 4114, are rapidly degraded under conditions that simulate the mammalian digestive tract, and are unstable under heating conditions expected to be encountered during processing of some corn products.

Novel PAT protein

To obtain sufficient quantities of PAT protein for evaluation of environmental and feed safety, it was necessary to express the pat gene in a microbial production system. Equivalency was demonstrated between corn event 4114-produced PAT protein and a microbial-produced PAT protein that had been used in studies previously submitted for Pioneer Hi-Bred Production Ltd.'s corn events 1507 (DD2002-41) and 59122 (DD2005-55), based on the same amino acid sequence and similar molecular weights and immunoreactivities. Demonstration of equivalence between the PAT protein produced in corn event 4114 and the microbially-produced PAT protein used in studies submitted for corn events 1507 and 59122 allows utilization of information from these studies to confirm the safety of the PAT protein produced in corn event 4114.

The potential mammalian allergenicity and toxicity of the PAT protein was evaluated. With respect to its potential allergenicity, it is recognized that no single experimental method yields decisive evidence for allergenicity, thus a weight-of-evidence approach was taken, taking into account information obtained with various test methods. The source of the pat gene, S. viridochromogenes, is not known to produce allergens and a bioinformatics evaluation of the PAT amino acid sequence confirmed the lack of relevant similarities between the PAT protein and known allergens. Unlike many allergens, microbial PAT safety studies previously provided for corn events 1507 and 59122 indicated that the PAT protein is readily degraded in simulated mammalian gastric fluid. The weight of evidence thus indicates that the PAT protein is unlikely to be allergenic.

In terms of its potential toxicity, the PAT protein lacks a mode of action to suggest that it is intrinsically toxic to livestock and a bioinformatics evaluation of the PAT protein's amino acid sequence confirmed the lack of relevant similarities between the PAT protein and known toxins. In addition, microbial PAT protein safety studies previously provided for corn events 1507 and 59122 indicated that no adverse effects were observed when the PAT protein was ingested by mice at approximately 5000 mg/kg bwt. This information indicates that the PAT protein is unlikely to be toxic to livestock.

The livestock exposure to the PAT protein is expected to be negligible as the PAT protein is expressed at very low levels in corn event 4114 and is rapidly degraded under conditions that simulate the mammalian digestive tract.

Chemical pesticide residue profile

The safety of the glufosinate-ammonium herbicide residues and metabolites in corn event 4114, following application of the herbicide, was also evaluated as part of the feed safety assessment.

It was determined that that potential glufosinate-ammonium residues and metabolites in livestock commodities derived from corn grain and forage from corn event 4114, did not present levels of concern to livestock, nor humans, via the potential transfer into foods of animal origin.

Additional safety data

An additional study with corn event 4114 was provided by Pioneer Hi-Bred Production Ltd. Rats were fed ad libitum diets composed of 32% (wt/wt) corn for 90 days. Three different diets were made using grain from corn event 4114 plants that were treated with glufosinate-ammonium in the field, from untreated corn event 4114 plants, or from the unmodified control corn variety. An evaluation of the study failed to establish adverse treatment-related effects from the feeding of corn event 4114.

Conclusions

Feed ingredients derived from corn event 4114 are considered to meet present ingredient definitions for corn and as such are approved for use as livestock feed in Canada.

VI. New information requirements

If at any time Pioneer Hi-Bred Production Ltd. becomes aware of any new information regarding risk to the environment, including risk to human or animal health, that could result from release of corn event 4114 or lines derived from it, Pioneer Hi-Bred Production Ltd. is required to immediately provide such information to the CFIA. On the basis of such new information, the CFIA will re-evaluate the potential impact of corn event 4114 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 4114.

VII. Regulatory decision

Based on the review of the data and information submitted by Pioneer Hi-Bred Production Ltd. and input from other relevant scientific sources, the PBRA Unit of the Plant Health Science Directorate, CFIA has determined that the unconfined environmental release of corn event 4114 does not present altered environmental risk when compared to corn varieties that are currently grown in Canada.

Based on the review of the data and information submitted by Pioneer Hi-Bred Production Ltd., and input from other relevant scientific sources, the Animal Feed Division of the Animal Health Directorate, CFIA, has concluded that the novel Cry1F, Cry34Ab1, Cry35Ab1 protein-based insect resistance traits and PAT protein-based herbicide tolerance trait will not confer to corn event 4114 any characteristic that would raise any concerns regarding the safety or nutritional composition of corn event 4114. 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 4114 has been found to be as safe as and as nutritious as currently and historically grown corn varieties. Corn event 4114 and its products are considered to meet present ingredient definitions and are approved for use as livestock feed ingredients in Canada.

Unconfined release into the environment and use as livestock feed of corn event 4114 are 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 June 21, 2013. Any corn lines derived from corn event 4114 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 corn varieties that are currently grown and permitted to be used as livestock feed 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.

Additionally, with respect to its unconfined release into the environment, the insect management requirements described in the authorization for corn event 4114 must be applied.

Corn event 4114 is subject to the same phytosanitary import requirements as unmodified corn varieties. Corn event 4114 is required to meet the requirements of other jurisdictions, including but not limited to, the Food and Drugs Act and the Pest Control Products Act.

Please refer to Health Canada's Decisions on Novel Foods for a description of the food safety assessment of corn event 4114.

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