Decision Document DD2015-112
Determination of the Safety of Monsanto Canada Inc.'s Corn (Zea mays L.) Event MON 87403

This page is part of the Guidance Document Repository (GDR).

Looking for related documents?
Search for related documents in the Guidance Document Repository

This Decision Document has been prepared to explain the regulatory decisions reached under Directive 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.) (Corn) 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 Monsanto Canada Inc. This information concerns the increased ear biomass corn event MON 87403. 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 or nutrition 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 MON 87403 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, respectively, as of November 18, 2015. Any corn lines derived from corn event MON 87403 may also be released into the environment and used as livestock feed, provided that:

  1. no inter-specific crosses are performed;
  2. the intended use(s) are similar;
  3. 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 nutrition; and
  4. the novel gene is expressed at a level similar to that of the authorized line.

Corn event MON 87403 is subject to the same phytosanitary import requirements as unmodified corn varieties, and is required to meet the requirements of other Canadian legislation, including but not limited to, the Food and Drugs Act and the Pest Control Products Act.

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

November 18, 2015

This bulletin was created by the Canadian Food Inspection Agency. For further information, please contact the Plant Biosafety Office or the Animal Feed Division by visiting the contact page.

Table of Contents

I. Brief Identification of the Modified Plant

Designation of the Modified Plant: Corn event MON 87403

Applicant: Monsanto Canada Inc.
Plant Species: Corn (Zea mays L.)
Novel Traits: Increased ear biomass
Trait Introduction Method: Agrobacterium-mediated transformation
Intended Use of the Modified Plant: Corn event MON 87403 is intended for traditional corn human food and livestock feed uses. Corn event MON 87403 is not intended to be grown outside the normal production area for corn in Canada.

II. Background Information

Monsanto Canada Inc. has developed a corn event that has increased ear biomass. Corn event MON 87403 was developed by Monsanto Canada Inc. using recombinant deoxyribonucleic acid (rDNA) technology, resulting in the introduction of the coding region of the full-length ATHB17 gene from Arabidopsis thaliana. In corn event MON 87403, maize-specific splicing of the ATHB17 transcript resulted in a truncated protein, ATHB17Δ113, missing the first 113 N-terminal amino acids expressed in A. thaliana. ATHB17Δ113 can alter the activity of endogenous maize HD-Zip II proteins, which are predominantly expressed in ear tissue, and have been shown to play an important role in the modulation of plant growth and development. Thus, the ATHB17Δ113 protein likely modulates HD-Zip II-regulated pathways in the ear, which may lead to increased ear growth at the early reproductive phase.

Monsanto Canada Inc. has provided information on the identity of corn event MON 87403, a detailed description of the transformation method and information on insert copy number and intactness, levels of protein expression in the plant and the role of the inserted sequences. The novel protein was identified and characterized. Information was provided for the evaluation of the potential toxicity of the novel protein to livestock and non-target organisms and potential allergenicity of the novel protein to humans and to livestock.

To assess the agronomic characteristics of corn event MON 87403, it was field tested at 13 sites in the United States (US) in 2012, of which 10 were considered to be representative of major Canadian corn growing regions. Corn event MON 87403 was also field tested at 3 locations in Canada in the 2013 growing season. Corn event MON 87403 was compared to an unmodified control corn hybrid with a similar genetic background. Several reference corn hybrids were also included in the field trials to establish ranges of comparative values that are typical of currently grown corn varieties. Agronomic characteristics of corn event MON 87403, including plant 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, grain moisture, test weight and yield, were compared to those of the unmodified control corn hybrid and to the range established by the reference corn hybrids.

To assess the nutritional components of corn event MON 87403 grain and forage, it was field tested at 8 field trial sites in the US during the 2012 growing season. Nutritional components of corn event MON 87403 grain and forage, such as protein, fat, moisture, ash, amino acids, fatty acids, vitamins, minerals and anti-nutrients were compared to those of the unmodified control corn hybrid and to the range established by the reference corn hybrids.

The Plant and Biotechnology Risk Assessment Unit of the Plant Health Science Directorate, CFIA, has reviewed the above information, in light of the assessment criteria for determining environmental safety of PNTs, 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 potential for corn event MON 87403 to become a weed of agriculture or to be invasive of natural habitats;
  • the potential for gene flow from corn event MON 87403 to sexually compatible plants whose hybrid offspring may become more weedy or more invasive;
  • the potential for corn event MON 87403 to become a plant pest;
  • the potential impact of corn event MON 87403 and its gene products on non-target organisms, including humans; and
  • the potential impact of corn event MON 87403 on biodiversity.

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 nutrition 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 MON 87403 and unmodified corn varieties relative to the safety and nutrition of feed ingredients derived from corn event MON 87403 for their intended purpose, including:

  • the potential impact of corn event MON 87403 on livestock nutrition; and
  • the potential impact of corn event MON 87403 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.

The AFD has also considered whether feeds derived from corn event MON 87403 meet the definitions and requirements of feeds as listed in Schedule IV of the Feeds Regulations.

III. Description of the Novel Trait

1. Development Method

Corn event MON 87403 was developed through Agrobacterium-mediated transformation using corn immature embryos from inbred line LH244 utilizing PV-ZMAP5714 plasmid. PV-ZMAP5714 contained the coding region of the full-length Arabidopsis thaliana ATHB17 gene, and the plasmid backbone contained the cp4 epsps selectable marker cassette and the aadA expression cassette. Initial selection of transformants was performed using the cp4 epsps. Conventional breeding and molecular analysis were then used to select plants containing only the intended T-DNA (and not the cp4 epsps). In corn event MON 87403, maize-specific splicing of the ATHB17 transcript resulted in a truncated protein, ATHB17Δ113, missing the first 113 N-terminal amino acids that are present in Arabidopsis thaliana. Corn event MON 87403 was identified as a successful transformant based on molecular analyses, and was thus chosen for further development.

MON 87403 was developed through Agrobacterium-mediated transformation of maize immature embryos from inbred line LH244 utilizing PV-ZMAP5714. PV-ZMAP5714 is approximately 11.7 kb in size and contains three cassettes: one T-DNA, delineated by Left and Right Border regions, contains the ATHB17 expression cassette and the plasmid backbone contains the cp4 epsps selectable marker cassette and the aadA expression cassette. PV-ZMAP5714 employs a tandem T-DNA approach to generate marker-free plants. In this tandem T-DNA approach, a single right border and a single left border were used to achieve separate, unlinked insertion of the T-DNA as well as the cp4 epsps selectable marker gene located in the plasmid backbone. After initial selection of transformants using the cp4 epsps, conventional breeding followed by molecular analysis were used to select plants containing only the intended T-DNA (and not the cp4 epsps).

ATHB17 is a member of the HD-Zip family of plant transcription factors, which are proteins that bind to specific DNA sequences and regulate gene expression. The HD-Zip family of proteins is found broadly across plant species and specific HD-Zip proteins have been shown to play an important role in the modulation of plant growth and development. The HD-Zip family consists of four subfamilies and ATHB17 is a member of the class II subfamily. HD-Zip II proteins form either homodimers or heterodimers with other HD-Zip II proteins and function as repressors of gene expression. In corn event MON 87403, the ATHB17Δ113 protein is unable to function as a transcriptional repressor because the protein lacks a functional repression domain. By a dominant-negative mechanism, ATHB17Δ113 can alter the activity of endogenous maize HD-Zip II proteins, which are predominantly expressed in ear tissue. Thus, the ATHB17Δ113 protein likely modulates HD-Zip II-regulated pathways in the ear, which likely leads to increased ear growth at the early reproductive phase.

The ATHB17Δ113 protein expression in corn event MON 87403 is driven by a hybrid promoter comprising sequences from the CaMV 35S promoter and the promoter from the rice actin 1 gene. Over season leaf (OSL1), root (OSR1), forage and grain tissues were collected from plants from 5 field sites in the US. Tissues were collected from 4 replicate plots at all field sites. The average ATHB17Δ113 protein level among all tissue types was highest in OSL1 at 0.014 μg/g dry weight (dw) and lowest in grain at Limit Of Detection (LOD) μg/g dw.

To obtain sufficient quantities of ATHB17Δ113 protein for assessment of environmental and feed safety, it was necessary to express the ATHB17 gene in an Escherichia coli (E. coli) production system. Equivalency was demonstrated between the corn event MON 87403-produced ATHB17Δ113 protein and an E. coli-produced ATHB17Δ113 protein by immunoreactivity, N-terminal sequence analysis, MALDI TOF mass spectrometry, and by comparing their molecular weights. Based on the results, the proteins were found to be equivalent. Demonstration of equivalence between the ATHB17Δ113 protein produced in E. coli and the ATHB17Δ113 protein produced in corn event MON 87403 allows the ATHB17Δ113 protein produced in E. coli to be used in studies to confirm the safety of the ATHB17Δ113 protein produced in corn event MON 87403.

The potential allergenicity and toxicity of the ATHB17Δ113 protein to livestock and non-target organisms were evaluated. The weight of evidence indicates that the ATHB17Δ113 protein is unlikely to be allergenic, based on the following information. The source of the ATHB17 protein, Arabidopsis thaliana, is not commonly associated with allergenicity, the ATHB17Δ113 protein amino acid sequence lacks relevant similarities to known allergens. Unlike many allergens, the E. coli-produced ATHB17Δ113 protein was shown experimentally to be rapidly degraded in simulated gastric fluid. It was also concluded that the ATHB17Δ113 protein is unlikely to be toxic to livestock and non-target organisms because it lacks a mode of action to suggest that it is intrinsically toxic to livestock or non-target organisms. This is due to the fact that the ATHB17Δ113 protein amino acid sequence lacks relevant similarities to known toxins and because no adverse effects were observed when E. coli-produced ATHB17Δ113 protein was ingested by mice at doses of approximately 1335 mg/kg bwt. For a more detailed discussion of the potential allergenicity and toxicity of the ATHB17Δ113 protein (see Section V, part 2: Potential Impact of Corn Event MON 87403 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).

2. Stable Integration into the Plant Genome

Molecular characterization by Next-Generation Sequencing and Junction Sequence Analysis Bioinformatics Analyses (NGS/JSA) demonstrated that corn event MON 87403 contains one intact copy of the ATHB17 expression cassette inserted at a single locus in the corn genome. No additional elements, including intact or partial DNA fragments of the gene cassette or backbone sequences from the plasmid vector, linked or unlinked to the intact insert, were detected in corn event MON 87403.

The stability of the insert within corn event MON 87403 was verified by NGS/JSA over five breeding generations. The inheritance pattern of the insert and the ATHB17Δ113 protein expression trait across 5 segregating generations of corn event MON 87403 showed that the insert segregates according to Mendelian rules of inheritance for a single genetic locus.

IV. Criteria for the Environmental Assessment

1. Potential for Corn Event MON 87403 to Become a Weed of Agriculture or be Invasive of Natural Habitats

The biology of corn, as described in the CFIA biology document BIO1994-11 - The Biology of Zea mays L. (Corn), states that unmodified plants of this species are not invasive of unmanaged habitats in Canada. Corn does not possess an intrinsic potential to become weedy in Canada due to traits such as the lack of seed dormancy, the non-shattering nature of corn cobs and the poor competitive ability of seedlings. According to information provided by Monsanto Canada Inc., corn event MON 87403 was determined not to be significantly different from unmodified corn varieties in this respect.

The CFIA evaluated data submitted by Monsanto Canada Inc. on the reproductive biology and life history traits of corn event MON 87403. As previously mentioned, this event was field tested in the US at 13 locations in 2012, of which 10 were considered to be representative of major Canadian corn growing regions. It was also field tested at 3 locations in Canada in 2013. During the field trials, corn event MON 87403 was compared to the unmodified control corn hybrid. Reference corn hybrids were also included in these trials to establish ranges of comparative values that are representative of currently grown corn varieties. 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 plant 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, grain moisture, test weight and yield.

Although instances of statistically significant differences were observed between corn event MON 87403 and the unmodified control corn hybrid for some traits in the individual-site analyses, there was only one consistent trend related to increased ear height in the combined-site analyses. However, the values for increased ear height were within the range established by the reference corn hybrids included in the same field trials. Since the values were within established ranges, the results were not considered to be biologically meaningful.

Monsanto Canada Inc. provided information on the dormancy and germination of corn event MON 87403 seed under 7 different temperature regimes. Seed germination characteristics were evaluated, including percent germinated seed (normal and/or abnormal), percent viable hard seed, percent dead seed and percent viable firm swollen seed. Corn event MON 87403 was compared to an unmodified control corn hybrid with a similar genetic background. Nine reference corn hybrids were included to provide a range of comparative values for each germination characteristics. Seed lots were produced at 3 sites in the US. Although instances of statistically significant differences were observed between corn event MON 87403 and the unmodified control corn hybrid for percent germinated abnormal seed and percent viable firm swollen seed, these differences were small in magnitude or within the range established by the reference corn hybrids and were not consistently detected across temperature regimes. Therefore, the introduction of the novel trait did not impact the germination of the corn seed and did not confer dormancy to the corn seed.

Monsanto Canada Inc. provided information on the pollen viability and morphology of corn event MON 87403. Pollen characteristics were evaluated, including viability, diameter and general morphology. Corn event MON 87403 was compared to an unmodified control corn hybrid with a similar genetic background. Four reference corn hybrids were included to provide a range of comparative values for each pollen characteristics. Seed lots were produced at a single site in the US. No statistically significant differences were detected between corn event MON 87403 and the unmodified control corn hybrid for percent viable pollen or pollen grain diameter. Furthermore, no visual differences were observed in general pollen morphology between corn event MON 87403 and the unmodified control corn hybrid.

The volunteer potential of corn event MON 87403 was assessed at 4 sites in the US. Corn event MON 87403 seeds were seeded in the fall of 2012. No volunteer plants for corn event MON 87403, the unmodified control corn hybrid or any of the reference corn hybrids were observed at any of the 4 sites when inspected two weeks after planting until environmental conditions were no longer conducive for germination or in 2013.

The susceptibility of corn event MON 87403 to various abiotic stressors was evaluated in the same locations as the agronomic characteristic studies. The stressors observed included cold, drought, flood, frost, hail, heat, nutrient deficiency, soil compaction, sunscald and wind. No qualitative differences were observed for any of the 143 observations between corn event MON 87403 and the unmodified control corn hybrid.

The susceptibility of corn event MON 87403 to various corn pests and pathogens was evaluated in the field at the same locations as the agronomic characteristic studies (further detail provided below in Section IV, part 3: Potential for Corn Event MON 87403 to Become a Plant Pest). No trend in increased or decreased susceptibility to pests or pathogens was observed in corn event MON 87403 compared to the unmodified control corn hybrid.

The novel trait has no intended or observed effects on weediness or invasiveness. No competitive advantage was conferred to plants of corn event MON 87403, as the reproductive and growth characteristics, and tolerance to abiotic and biotic stresses of corn event MON 87403 were comparable to those of the unmodified control corn hybrid and reference corn hybrids.

The CFIA has therefore concluded that corn event MON 87403 has no altered weediness or invasiveness potential in Canada compared to currently grown corn varieties.

2. Potential for Gene Flow from Corn Event MON 87403 to Sexually Compatible Plants Whose Hybrid Offspring May Become More Weedy or More Invasive

The CFIA biology document BIO1994-11 - The Biology of Zea mays (L.) (Corn) states that there are no sexually compatible species in Canada that can hybridize with corn. The trait of increased ear biomass in corn is unrelated to sexual compatibility.

The CFIA has therefore concluded that gene flow from corn event MON 87403 to sexually compatible relatives is not possible in Canada.

3. Potential for Corn Event MON 87403 to Become a Plant Pest

Corn is not considered a plant pest in Canada and the increased ear biomass trait introduced into corn event MON 87403 is 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 MON 87403 to various corn pests and pathogens was evaluated in the field at the same locations as the agronomic characteristic studies. The stressors observed included aphids (Aphididae), armyworms (Noctuidae), bean leaf beetles (Cerotoma trifurcate), billbugs (Shenophorus parvulus), Corn earworms (Helicoverpa zea), corn flea beetles (Chaetocnema pulicaria), corn rootworm beetles (Diabrotica sp.), European corn borers (Ostrinia nubilalis), grasshoppers (Melanoplus spp.), Japanese beetles (Popillia japonica), June beetles (Scarabaeidae), sap beetles (Nitidulidae), slugs (Gastropoda), southwestern corn borer (Diatraea grandiosella), spider mites (Tetranychus sp.), stink bugs (Pentatomidae), western bean cutworm (Richia albicosta), click beetles (Elaridae), anthracnose, bacterial leaf spot, ear rot, eyespot, Fusarium sp., Goss's bacterial wilt, gray leaf spot, leaf blight, maize rough dwarf virus, northern leaf spot, Pythium sp., Rhizoctonia sp., rust, seedling blight and smut. The evaluations of corn event MON 87403 did not show any increase or decrease in susceptibility to pest stressors compared to the unmodified control corn hybrid for any of the 150 observations for plant damage caused by arthropods. Furthermore, no qualitative differences were observed between corn event MON 87403 and the unmodified control corn hybrid for any of the 176 observations for plant damage caused by diseases.

Monsanto Canada Inc. quantitatively assessed corn earworm and European corn borer damage in the field at 4 of the locations where the agronomic characteristic studies were conducted. No statistically significant differences were detected between corn event MON 87403 and the unmodified control corn hybrid for corn earworm and European corn borer damage.

Monsanto Canada Inc. quantitatively assessed arthropod abundance using sticky traps and visual counts at 4 of the locations where the agronomic characteristic studies took place. For the sticky traps method, the stressors observed included aphids (Aphididae), billbugs (Curculionidae), corn flea beetles (Chaetocnema sp.), corn rootworm beetles (Diabrotica sp.), delphacid planthoppers (Delphacidae), grasshoppers (Orthoptera), lacewings (Chrysopidae), ladybird beetles (Coccinellidae), leafhoppers (Cicadellidae), macro-parasitic hymenoptera, micro-parasitic hymenoptera, minute pirate bugs (Anthocoridae), damsel bugs (Nabidae), sap beetles (Nitidulidae), seedcorn beetles (Stenolophus sp.), spiders (Araneae), syrphid flies (Syrphidae), tachinid flies (Tachinidae), tarnished plant bugs (Lygus sp.), thrips (Thripidae) and click beetles (Elateridae). No statistically significant differences were observed between corn event MON 87403 and the unmodified control corn hybrid for 130 out of 144 observations. Although 14 statistically significant differences were detected between corn event MON 87403 and the unmodified control corn hybrid for lacewings, macro-parasitic hymenoptera, micro-parasitic hymenoptera, aphids, corn flea beetles, corn rootworms and thrips, these differences were not indicative of a consistent result across sites and are unlikely to be biologically meaningful. For the visual counts method, the stressors observed included ant-like flower beetles (Anthicidae), corn flea beetles (Chaeticnema sp.), Japanese beetles (Scarabaiedae), lacewing adults (Chrysopidae), lacewing larvae (Chrysopidae), ladybird beetle adults (Coccinellidae), ladybird beetle larvae (Coccinellidae), minute pirate bugs (Anthocoridae), corn rootworm beetles (Chrysomelidae), sap beetles (Nitidulidae), shinning flower beetles (Phlacridae), spider (Araneae), stink bugs (Pentatomidae) and click beetles (Elateridae). No statistically significant differences were observed between corn even MON 87403 and the unmodified control corn hybrid for 61 out of 66 observations. Although 5 statistically significant differences were detected between corn event MON 87403 and the unmodified control corn hybrid for minute pirate bugs, corn rootworm beetles, sap beetles and shinning flower beetles, these differences were not indicative of a consistent result across sites and are unlikely to be biologically meaningful.

The CFIA has therefore concluded that corn event MON 87403 does not display any altered plant pest potential compared to currently grown corn varieties.

4. Potential Impact of Corn Event MON 87403 or Its Gene Products on Non-Target Organisms, including Humans

The increased ear biomass trait introduced into corn event MON 87403 is unrelated to a potential impact on non-target organisms.

Detailed characterization of the ATHB17Δ113 protein expressed in corn event MON 87403 led to the conclusion that the protein does not display any characteristic of a potential toxin or allergen (see Section V, part  2: Potential Impact of Corn Event MON 87403 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). In addition, bioinformatic searches using the ATHB17Δ113 amino acid sequence as the query identified homologous sequences from several different food plants, including soybean, rice, corn tomato, potato, orange, papaya, grape and cruciferous vegetables. Thus, ATHB17Δ113 shares sequence identity and structural similarity with proteins present in plants currently consumed, establishing that humans and animals are exposed to this class of proteins with no adverse effects. As a result, no negative impacts resulting from exposure of organisms to the ATHB17Δ113 protein expressed in corn event MON 87403 are expected.

Composition analyses showed that the levels of key nutrients and anti-nutrients in grain and forage from corn event MON 87403 are comparable to those in reference corn hybrids (see Section V, part 1: Potential Impact of Corn Event MON 87403 on Livestock Nutrition). Therefore, it is very unlikely that the introduction of the novel trait may have caused unintended changes to the composition of corn event MON 87403 tissues that would negatively impact organisms interacting with corn event MON 87403.

Field evaluations of corn event MON 87403 did not show any increased resistance to insect pests or pathogens compared to the unmodified control corn hybrid (see Section IV, part 3: Potential for Corn Event MON 87403 to Become a Plant Pest).

Collectively, these information elements indicate that the interactions between corn event MON 87403 and the populations of animals and microorganisms interacting with corn crops will be similar compared to currently grown corn varieties.

The CFIA has therefore determined that the unconfined environmental release of corn event MON 87403 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 MON 87403 on Biodiversity

Corn event MON 87403 expresses no novel phenotypic characteristics that would extend its range beyond the current geographic range of corn production in Canada. Since corn has no sexually compatible relatives with which it can outcross in Canada, there will be no transfer of the novel trait to other species in unmanaged environments. Corn event MON 87403 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 MON 87403 will have any direct effects on biodiversity, in comparison to the effects that would be expected from the cultivation of corn varieties that are currently grown in Canada.

The CFIA has concluded that the introduced gene and its corresponding novel trait do not confer to corn event MON 87403 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 MON 87403 is unlikely to be different from that of the corn varieties that are currently grown in Canada.

V. Criteria for the Livestock Feed Assessment

The AFD considered nutrient and anti-nutrient profiles; the safety of feed ingredients derived from corn event MON 87403, 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 MON 87403 meet the definitions and requirements of feeds as listed in Schedule IV of the Feeds Regulations.

1. Potential Impact of Corn Event MON 87403 on Livestock Nutrition

Nutrient and Anti-Nutrient Composition

The nutritional equivalence of corn event MON 87403 plants to those of the unmodified control corn variety and 17 reference corn hybrids was determined from eight replicated field trial sites in the US during the 2012 growing season. Forage and grain samples were analysed for moisture, ash, protein, crude fat, carbohydrates (by calculations), acid detergent fibre (ADF), neutral detergent fibre (NDF), calcium and phosphorus. Grain samples were further analysed for amino acids, total detergent fibre (TDF), fatty acids, vitamins, minerals, secondary metabolites (ferulic acid and p-coumaric acid) and anti-nutrients (phytic acid and raffinose) as recommended by the OECD consensus document for new varieties of corn (OECD, 2001 - PDF (190 kb)). Corn compositional components were statistically analyzed using a mixed model analysis of variance, and statistical differences among treatments were identified and assessed (P<0.05). The biological relevance of any significant difference among corn varieties was assessed by comparing the observed values to the range of the values observed in the reference corn hybrids grown in the trials and in the published scientific literature (ILSI, 2011 - PDF (5 kb)).

No statistically significant differences were observed between the unmodified control corn variety and corn event MON 87403 forage and grain for protein, fat, ash, carbohydrates, ADF, NDF, TDF (grain), calcium and phosphorus. All mean values of corn event MON 87403 were within the range of the values observed in the reference corn hybrids grown in the trials and in the published scientific literature (ILSI, 2011). No statistically significant differences were observed between the unmodified control corn variety and corn event MON 87403 for all amino acids, minerals, vitamins and fatty acids analysed. All mean values of corn event MON 87403 were within the range of the values observed in the reference corn hybrids grown in the trials and in the published scientific literature (ILSI, 2011). The secondary metabolites; ferulic acid and p-coumaric acid and the anti-nutrients; phytic acid and raffinose in corn event MON 87403 were not statistically significant different from the values for the unmodified control corn variety. All mean values of corn event MON 87403 were within the range of the values observed in the reference corn hybrids grown in the trials and in the published scientific literature (ILSI, 2011).

Broiler Performance

800 broilers were distributed randomly to 80 pens (10 birds per pen) to examine the health and performance of birds from feeding diets from corn event MON 87403, the unmodified control corn variety, and six reference corn hybrids in a 42-day trial. The performance and mortality data of birds on corn event MON 87403 diets were not statistically significantly different from birds on the diets containing the unmodified control corn variety and the reference corn hybrids over the entire trial. No statistically significant differences were observed between broilers fed corn event MON 87403 diets and those fed the unmodified control corn variety diets for feed intake, average daily gain and feed efficiency. Carcass yield measurements and tissue weights were not statistically significantly different for broilers fed diets containing corn event MON 87403 compared to those fed diets containing the unmodified control corn variety or the reference corn hybrids. No unexpected effects on broiler performance and health were found when broilers were fed diets containing corn event MON 87403.

Conclusion

It was concluded, based on the evidence provided by Monsanto Canada Inc., that the nutritional composition of corn event MON 87403 is similar to those of the reference corn hybrids grown in the trials and to that reported for other corns in the published scientific literature. Feed ingredients derived from corn event MON87403 are considered to meet present ingredient definitions for corn in terms of nutritional composition.

2. Potential Impact of Corn Event MON 87403 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 MON 87403 has increased ear biomass at the early reproductive phase compared to conventional control maize grown under comparable environmental conditions. This is achieved through the production of ATHB17Δ113, a maize truncated ATHB17 protein missing the first 113 N-terminal amino acids. ATHB17 protein is part of HD-Zip II subfamily of plant transcription factors, predominantly expressed in ear tissue, that have been shown to play an important role in the modulation of plant growth and development. ATHB17Δ113, can bind to target DNA as would the full length protein but lacks the functional repression domain and is unable to function as a transcriptional repressor. This interaction without repression results in increased ear growth at the early reproductive phase leading to improved ear biomass.

The assessment of corn event MON 87403 evaluated the impact of the potential hazards of the novel ATHB17Δ113 protein in relation to the safety of feed ingredients derived from this corn event.

Novel ATHB17Δ113 protein

To obtain sufficient quantities of ATHB17Δ113 protein for assessment of environmental and feed safety, it was necessary to express the ATHB17 gene in an E. coli production system. Equivalency was demonstrated between corn event MON 87403-produced ATHB17Δ113 protein and an E. coli-produced ATHB17Δ113 protein using a panel of analytical techniques, including: 1) SDS-PAGE analysis, to establish equivalence of apparent molecular weight between the corn event MON 87403-produced and E. coli-produced ATHB17Δ113 proteins; 2) western blot analysis with antibodies specific for the ATHB17Δ113 protein to establish immunoreactive equivalence between the corn event MON 87403-produced and E. coli-produced ATHB17Δ113 proteins; and 3) MALDI TOF MS analysis of corn event MON 87403-produced ATHB17Δ113 to establish protein identity. Furthermore, equivalence of N-terminal sequences, specific DNA binding activity, and glycosylation status were assessed indirectly and based on the results, the proteins were found to be equivalent. Demonstrated equivalence between the ATHB17Δ113 protein produced in E. coli and the ATHB17Δ113 protein produced in corn event MON87403 allows the ATHB17Δ113 protein produced in E. coli to be used in studies to confirm the safety of the ATHB17Δ113 protein produced in corn event MON 87403.

The potential allergenicity and toxicity of the ATHB17Δ113 protein to livestock was evaluated. With respect to its potential allergenicity, no single experimental method yields decisive evidence, thus a weight-of-evidence approach was taken, taking into account information obtained with various test methods. The source of the ATHB17gene, A. thaliana, is not known to produce allergens and a bioinformatics evaluation of the ATHB17Δ113 protein amino acid sequence confirmed the lack of relevant similarities between the ATHB17Δ113 protein and known allergens. E. coli-produced ATHB17Δ113 protein safety studies indicated that, unlike many allergens, this protein is rapidly degraded in simulated gastric and intestinal fluids. Finally, unlike many allergens, corn event the ATHB17Δ113 protein expressed in MON87403 is not expected to be glycosylated since there are no predicted N-terminal targeting or signal sequences in the ATHB17Δ113 amino acid sequence due to the truncation of the N-terminus of the protein. Since the N-terminal signal sequence is required for transport to the endoplasmic reticulum, which is the site of glycosylation, the absence of this sequence supports a conclusion that the corn event MON 87403-produced ATHB17Δ113 protein is not glycosylated. The weight of evidence thus indicates that the ATHB17Δ113 protein is unlikely to be allergenic.

In terms of its potential toxicity to livestock, the ATHB17Δ113 protein lacks a mode of action to suggest that it is intrinsically toxic to livestock and a bioinformatics evaluation of the ATHB17Δ113 protein amino acid sequence confirmed the lack of relevant similarities between the ATHB17Δ113 protein and known toxins. In addition, the safety studies conducted with E. coli-produced ATHB17Δ113 protein indicated that no adverse effects were observed when the ATHB17Δ113 protein was ingested by mice at doses of approximately 1335 mg/kg body weight. This information indicates that the ATHB17Δ113 protein is unlikely to be toxic to livestock.

The livestock exposure to the ATHB17Δ113 protein is expected to be negligible as the ATHB17Δ113 protein is expressed at very low levels in corn event MON 87403 and is rapidly degraded under conditions which simulate the mammalian digestive tract.

Conclusion

It was concluded, based on the evidence provided by Monsanto Canada Inc., that the novel increased ear biomass at the early reproductive phase trait will not confer to corn event MON 87403 any characteristic that would raise concerns regarding the safety of corn event MON 87403. Feed ingredients derived from corn event MON 87403 are considered to meet present ingredient definitions for corn.

VI. New Information Requirements

If at any time, Monsanto Canada Inc. becomes aware of any new information regarding risk to the environment, livestock or human health, which could result from the unconfined environmental release or livestock feed use of corn event MON 87403 or lines derived from it, Monsanto Canada Inc. 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 MON 87403 on the environment, livestock and human health and may re-evaluate its decision with respect to the livestock feed use and unconfined environmental release authorizations of corn event MON 87403.

VII. Regulatory Decision

Based on the review of the data and information submitted by Monsanto Canada Inc., and input from other relevant scientific sources, the Plant and Biotechnology Risk Assessment Unit of the Plant Health Science Directorate, CFIA, has concluded that the unconfined environmental release of corn event MON 87403 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 Monsanto Canada Inc., and input from other relevant scientific sources, the Animal Feed Division of the Animal Health Directorate, CFIA, has concluded that the novel ATHB17Δ113 protein-based increased ear biomass trait will not confer to corn event MON 87403 any characteristic that would raise concerns regarding the safety or nutrition of corn event MON 87403. Livestock feeds derived from corn are currently listed in Schedule IV of the Feeds Regulations. Corn event MON 87403 has been found to be as safe as and as nutritious as currently and historically grown corn varieties. Corn event MON 87403 and its products are considered to meet present ingredient definitions.

Unconfined release into the environment and use as livestock feed of corn event MON 87403 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, respectively, as of November 18, 2015. Any corn lines derived from corn event MON 87403 may also be released into the environment and used as livestock feed, provided that:

  1. no inter-specific crosses are performed;
  2. the intended uses are similar;
  3. 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 nutrition; and
  4. the novel gene is expressed at a level similar to that of the authorized line.

Corn event MON 87403 is subject to the same phytosanitary import requirements as unmodified corn varieties and is required to meet the requirements of other Canadian legislation 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 MON 87403.

Date modified: