Decision Document DD2017-119
Determination of the Safety of E. I. du Pont Canada Company's Sorghum (Sorghum bicolor (L.) Moench) Event Inzen™

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 document BIO2017-01: The Biology of Sorghum bicolor (L.) Moench (Sorghum) 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 E. I. du Pont Canada Company. This information concerns the herbicide tolerant sorghum event Inzen. The CFIA has determined that this plant with 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 sorghum varieties currently grown and permitted to be used as livestock feed in Canada.

Taking into account the conclusion of the environmental risk assessment and recognizing that incidental release into the environment could occur when this PNT is used as intended, unconfined release into the environment of sorghum event Inzen and of any lines derived from it is therefore authorized by the Plant Biosafety Office of the Plant Health and Biosecurity Directorate as of July 4, 2017 on a condition that no sale of seed takes place in Canada. This condition is being applied to ensure that the PNT is used as intended.

Taking into account livestock feed assessment, use as livestock feed of sorghum event Inzen and of any lines derived from it is authorized by the Animal Feed Division of the Animal Health Directorate as of July 4, 2017.

Authorizations of the sorghum lines derived from sorghum event Inzen are conditional on the following:

  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 sorghum 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 genes are expressed at levels similar to those of the authorized line.

Sorghum event Inzen is subject to the same phytosanitary import requirements as unmodified sorghum varieties. Sorghum event Inzen is required to meet the requirements of other Canadian legislation, including but not limited to, the requirements set out in the Food & Drugs Act and the Pest Control Products Act.

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

July 4, 2017

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:
Sorghum event Inzen
Applicant:
E. I. du Pont Canada Company
Plant Species:
Sorghum (Sorghum bicolor (L.) Moench)
Novel Traits:
Tolerance to sulfonylurea and imidazolinone herbicides
Trait Introduction Method:
Conventional breeding
Intended Use of the Modified Plant:
Sorghum event Inzen is intended for conventional sorghum livestock feed, human food and industrial uses. Sorghum event Inzen and derived lines will be grown outside Canada, in the usual production areas for sorghum. Grain and by-products derived from Sorghum event Inzen will be imported into Canada for livestock feed use only.

II. Background Information

E. I. du Pont Canada Company has developed a sorghum event that is tolerant to sulfonylurea and imidazolinone herbicides. Sorghum event Inzen was developed by E. I. du Pont Canada Company through conventional breeding and selection techniques resulting in the introgression of tolerance to group 2 herbicides (e.g. sulfonylurea and imidazolinone) from wild sorghum (shattercane; Sorghum bicolor L.) into grain sorghum (Sorghum bicolor (L.) Moench). The herbicide tolerance is derived from naturally occurring mutations in the acetolactate synthase als gene of wild sorghum (shattercane; Sorghum bicolor L.). The mutated als gene contained two single nucleotide polymorphisms (SNPs) resulting in two amino acid substitutions, a valine to isoleucine substitution at position 560 and a tryptophan to leucine substitution at position 574. These mutations prevent binding of specific group 2 herbicides to the ALS protein, and therefore confer tolerance to the herbicides.

E. I. du Pont Canada Company has provided information on the identity of sorghum event Inzen, a detailed description of the selective breeding history, information on the modified gene, the stability of trait expression, the resulting modified protein and its mode of action, as well as the enzymatic activity of modified protein in the plant. The modified ALS protein was identified and characterized. Information was provided for the evaluation of the potential toxicity of the modified protein to livestock and non-target organisms and potential allergenicity of the modified protein to humans and to livestock.

Sorghum event Inzen was field tested at five sites in the United States (US) in 2013. An unmodified control sorghum variety, which shares the same genetic background as sorghum event Inzen, was included in the trials to act as a comparator for sorghum event Inzen. Four reference sorghum varieties were also included in the field trials to establish a reference range for typical sorghum behaviour.

Agronomic and phenotypic characteristics of sorghum event Inzen, such as early population count (emergence), seedling vigor, days to 50% bloom, plant height, lodging, and final population, were compared to those of the unmodified control sorghum variety and to the range established by the reference sorghum varieties.

Nutritional components of sorghum event Inzen grain and forage, such as protein, fat, moisture, ash, fibre, amino acids, fatty acids, vitamins, minerals and anti-nutrients were compared to those of the unmodified control sorghum variety and to the range established by the reference sorghum 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 PNTs, as described Directive 94-08 - Assessment Criteria for Determining Environmental Safety of Plants with Novel Traits. The PBRA Unit has considered:

  • the potential for sorghum event Inzen to become a weed of agriculture or to be invasive of natural habitats;
  • the potential for gene flow from sorghum event Inzen to sexually compatible plants whose hybrid offspring may become more weedy or more invasive;
  • the potential for sorghum event Inzen to become a plant pest;
  • the potential impact of sorghum event Inzen and its gene products on non-target organisms, including humans; and
  • the potential impact of sorghum event Inzen on biodiversity.

The Animal Feed Division (AFD) of the Animal Health Directorate, 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 sorghum event Inzen and unmodified sorghum varieties relative to the safety and nutrition of feed ingredients derived from sorghum event Inzen for their intended purpose, including:

  • the potential impact of sorghum event Inzen on livestock nutrition; and
  • the potential impact of sorghum event Inzen 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 sorghum event Inzen meet the definitions and requirements of sorghum derived feeds as listed in Schedule IV of the Feeds Regulations.

III. Description of the Novel Trait

1. Development Method

Sorghum event Inzen was developed by E. I. du Pont Canada Company through a conventional breeding program that resulted in the introgression of tolerance to group 2 herbicides (e.g. sulfonylurea and imidazolinone) from wild sorghum (shattercane; Sorghum bicolor L.) into grain sorghum (Sorghum bicolor (L.) Moench). Sorghum event Inzen was identified based on molecular analyses, herbicide efficacy and agronomic evaluations and chosen for further development.

2. Tolerance to Sulfonylurea and Imidazolinone Herbicides

Sulfonylurea and imidazolinone herbicides inhibit ALS proteins. ALS proteins catalyze the first step in the biosynthesis of branched chain amino acids, valine, leucine and isoleucine. The ALS-inhibiting herbicides bind to ALS proteins and block branched chain amino acid synthesis resulting in a lethal decrease in protein synthesis.

The two nucleotide mutations in the als gene in sorghum event Inzen resulted in two amino acid substitutions, a valine to isoleucine substitution at position 560 and a tryptophan to leucine substitution at position 574. The two amino acid substitutions in the sorghum event Inzen reduce the ability of ALS-inhibiting herbicides to bind to the active site of the ALS protein, which confers commercial-level tolerance to sulfonylurea and imidazolinone herbicides.

The modified ALS protein in sorghum event Inzen is under the control of the native constitutive promoter. The enzymatic activity of the ALS protein in sorghum event Inzen was compared to unmodified control sorghum variety as a substitute for relative levels of functional ALS protein expression. The data indicates that the amount of ALS protein in sorghum event Inzen is similar to unmodified control sorghum variety and the modified ALS protein resulted in herbicide tolerance trait in sorghum event Inzen.

The potential allergenicity and toxicity of the modified ALS protein to livestock and non-target organisms were evaluated. The weight of evidence indicates that the ALS protein is unlikely to be allergenic, based on the following information. The source of the als gene, shattercane; Sorghum bicolor L., is not commonly associated with allergenicity and the ALS protein amino acid sequence lacks relevant similarities to known allergens. It was also concluded that the ALS protein is unlikely to be toxic to livestock and non-target organisms because it lacks a mode of action that is intrinsically toxic to livestock or non-target organisms and the ALS protein amino acid sequence lacks relevant similarities to known toxins.

For a more detailed discussion of the potential allergenicity and toxicity of the modified ALS protein see Section V, part 2: Potential Impact of Sorghum event Inzen 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.

3. Stable Expression

The two nucleotide mutations in als gene in sorghum event Inzen were shown to be inherited according to Mendelian principles across five generations. The inheritance and stable expression of the herbicide-tolerance trait was verified by genotypic and phenotypic assays over five generations. A single nucleotide polymorphism (SNP) functional marker was used to confirm the presence of the mutated als gene in the sorghum genome. Moreover, phytotoxicity ratings of sorghum event Inzen treated with sulfonylurea herbicides demonstrated herbicide tolerance over multiple generations.

IV. Criteria for the Environmental Assessment

1. Potential for Sorghum Event Inzen to Become a Weed of Agriculture or be Invasive of Natural Habitats

The biology of sorghum, as described in CFIA biology document BIO2017-01 - The Biology of Sorghum bicolor L. (Sorghum) states that unmodified sorghum plants are not invasive of unmanaged habitats in Canada. Sorghum has some potential to become weedy due to the rapid growth, production of allelochemicals, high seed output, and ability to grow in a range of environmental conditions. According to the information provided by E.I. du Pont Canada Company, sorghum event Inzen was determined not to be significantly different from unmodified sorghum in this respect.

The CFIA evaluated data submitted by E.I. du Pont Canada Company on the reproductive biology and life history traits of sorghum event Inzen. As previously mentioned, a sorghum event Inzen was field-tested in the US at 5 locations in the 2013 growing season, of which two were considered to be representative of major Canadian sorghum growing regions. During the field trials, the sorghum event Inzen was compared to an unmodified control sorghum variety with a similar genetic background. Reference sorghum varieties were also included in these trials to establish a range of comparative values for each characteristic that are representative of currently grown sorghum varieties. The minimum and maximum comparative values each represent an individual data point for a single test plot. Phenotypic and agronomic traits were evaluated, covering a broad range of characteristics that encompass the entire life cycle of the sorghum plant. The traits included early population count (emergence), seedling vigor, days to 50% bloom, plant height, lodging, and final population.

No statistically significant differences were observed between the sorghum event Inzen and the unmodified control sorghum variety in early population count (emergence), days to 50% bloom, plant height, lodging, and final population. The seedling vigour of sorghum event Inzen was statistically significantly lower than the unmodified control sorghum variety; all but one value was within the ranges established from the reference sorghum varieties. A reduction in seedling vigour is not associated with an increase in weediness potential.

E.I. du Pont Canada Company provided information on the dormancy and germination of sorghum event Inzen seed under three different temperature regimes (warm, cold and diurnal). Seed germination characteristics were evaluated, including percent germinated seed (normal or abnormal) and percent ungerminated seed (hard, imbibed, or dead). A sorghum event Inzen was compared to an unmodified control sorghum variety. Two reference sorghum varieties were included to provide a range of comparative values for each germination characteristic. Statistically significant differences were not observed between sorghum event Inzen and the unmodified control sorghum variety under any regime for any seed category. Moreover, a lack of hard seed indicated that sorghum event Inzen does not possess seed dormancy. Therefore, the introduction of the novel traits did not impact the germination of the sorghum seed and did not confer dormancy to the sorghum seed.

Sorghum event Inzen is tolerant to sulfonylurea and imidazolinone herbicides due to two single nucleotide polymorphisms (SNPs) resulting in two amino acid substitutions in the ALS enzyme. The modification of the ALS enzyme is not expected to increase tolerance to abiotic stressors, beyond tolerance to sulfonylurea and imidazolinone herbicides.

The susceptibility of sorghum event Inzen to sorghum pests and pathogens was observed at five sites in 2013. No consistent trend in increased or decreased susceptibility to pests or pathogens was observed in sorghum event Inzen compared to the unmodified control variety.

No competitive advantage was conferred to sorghum event Inzen, other than that conferred by tolerance to ALS-inhibiting herbicides, as the reproductive characteristics, growth characteristics, and tolerance to pests and pathogens of sorghum event Inzen were comparable to those of the unmodified control sorghum variety.

Sorghum event Inzen is not intended to be cultivated in Canada, and seed is not authorized for sale to ensure this intended use. Therefore, environmental exposure to sorghum event Inzen plants will be minimal.

Based on the above information, the CFIA has concluded that sorghum event Inzen is unlikely to become a weed of agriculture or be invasive of natural habitats as a result of incidental environmental release.

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

The biology of sorghum, as described in CFIA biology document BIO2017-01 - The Biology of Sorghum bicolor L. (Sorghum) states that there are sexually compatible species in Canada that can hybridize with sorghum. If sorghum event Inzen is cultivated in Canada, the novel trait may transfer to other related species. The sulfonylurea and imidazolinone herbicide tolerance trait introduced into sorghum event Inzen has no intended effects on sorghum reproductive biology. The herbicide tolerance trait will not confer selective advantage to the wild relatives (with the exception of tolerance to ALS-inhibiting herbicides).

Sorghum event Inzen is not intended to be cultivated in Canada, and seed is not authorized for sale to ensure this intended use. Therefore, environmental exposure to sorghum event Inzen plants will be minimal.

Based on the above information, the CFIA has concluded that the potential for gene flow to sexually compatible species in Canada as a result of incidental environmental release is negligible.

3. Potential for Sorghum Event Inzen to Become a Plant Pest

Sorghum is not considered a plant pest in Canada and the sulfonylurea and imidazolinone herbicide tolerance trait introduced into sorghum event Inzen is unrelated to plant pest potential (e.g. the potential for the plant to harbor new or increased populations of pathogens or pests). The two SNPs resulting in two amino acid substitutions in the ALS enzyme (Val560→Ile and Trp574→Leu) are not intended or expected to impact the plant pest potential. No changes in plant pest potential have been reported in other commercialized crops with these amino acid substitutions.

Field observations did not indicate differences in the response sorghum event Inzen to biotic stressors including insects and diseases.

Sorghum event Inzen is not intended to be cultivated in Canada, and seed is not authorized for sale to ensure this intended use. Therefore, environmental exposure to sorghum event Inzen plants will be minimal.

Based on the above information, the CFIA has concluded that sorghum event Inzen would not be expected to display altered plant pest potential as a result of incidental environmental release.

4. Potential Impact of Sorghum Event Inzen and Its Gene Products on Non-Target Organisms, Including Humans

The sulfonylurea and imidazolinone herbicide tolerance trait introduced into sorghum event Inzen is unrelated to a potential impact on non-target organisms.

ALS proteins are not known toxins or allergens. Since the amino acid sequence of the mutated ALS enzyme in sorghum event Inzen differs by two amino acid substitutions, from that of unmodified sorghum, no changes in the allergenic or toxicological properties are anticipated (see Section V, part 2: Potential Impact of Sorghum Event Inzen 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). Therefore, no negative impacts resulting from exposure of organisms to the mutated ALS enzyme in sorghum event Inzen are expected.

Composition analyses showed that the levels of key nutrients and anti-nutrients in forage and grain derived from sorghum event Inzen are comparable to those in the unmodified control sorghum variety or reference sorghum varieties with the exception of protein, carbohydrates, some amino acids, and fatty acids; (palmitic acid [C16:0], palmitoleic acid [C16:1], linolenic acid [C18:3]) and eicosenoic acid [C20:1]. However these nutrients were within the normal variation found in reference sorghum varieties.

Two minor fatty acids: heptadecanoic acid [C17:0] and heptadecenoic acid [C17:1], were slightly elevated in Inzen sorghum grain. These minor fatty acids are widely distributed in nature, typical constituents of the human diet, and are readily metabolized by humans and animals; small changes in these fatty acids are not expected to affect non-target organisms (see Section V, part 1: Potential Impact of Sorghum event Inzen on Livestock Nutrition). Therefore, it is very unlikely that the introduction of the novel traits may have caused unintended changes to the composition of sorghum event Inzen tissues that would negatively impact organisms interacting with sorghum event Inzen.

The sulfonylurea and imidazolinone herbicide tolerance trait introduced into sorghum event Inzen is unrelated to plant pest potential (see Section IV, part 3: Potential for Sorghum Event Inzen to Become a Plant Pest).

Sorghum event Inzen is not intended to be cultivated in Canada, and seed is not authorized for sale to ensure this intended use. Therefore, environmental exposure to sorghum event Inzen plants will be minimal.

Based on the above information, the CFIA has concluded that sorghum event Inzen will not result in altered impacts on non-target organisms, including humans, as a result of incidental environmental release.

5. Potential Impact of Sorghum Event Inzen on Biodiversity

Sorghum event Inzen expresses no novel phenotypic characteristics that would extend its geographic range beyond the current range of sorghum production in Canada. Sorghum event Inzen is unlikely to cause adverse effects on non-target organisms and does not display increased weediness, invasiveness or plant pest potential.

Since sorghum has sexually compatible relatives it can outcross within Canada, if sorghum event Inzen is cultivated, the novel trait may transfer to other related species. Sorghum event Inzen is not intended to be cultivated in Canada, and seed is not authorized for sale to ensure this intended use. Therefore, environmental exposure to sorghum event Inzen plants will be minimal.

It is therefore unlikely that sorghum event Inzen will have any direct effects on biodiversity, in comparison to the effects that would be expected from the cultivation of the sorghum varieties that are currently grown in Canada.

Based on the above information, the CFIA has concluded that the potential impact on biodiversity of sorghum event Inzen would be minimal as a result of incidental environmental release.

V. Criteria for the Livestock Feed Assessment

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

1. Potential Impact of Sorghum Event Inzen on Livestock Nutrition

Nutrient and anti-nutrient composition

The nutritional equivalence of sorghum event Inzen to those of an unmodified control sorghum variety and four reference sorghum varieties was determined from five replicated field sites during the 2013 growing season in commercial sorghum-growing regions in the US. Forage and grain samples were collected and analyzed for proximates (protein, crude fat, ash, moisture), carbohydrates (by calculations); crude fibre (CF), acid detergent fibre (ADF), neutral detergent fibre (NDF), calcium and phosphorus. Grain samples were further analyzed for total dietary fibre (TDF); starch, amino acids, fatty acids, minerals, vitamins, and anti-nutrients (phytic acid and tannins) as recommended by the OECD consensus document for new varieties of sorghum (OECD, 2010 - PDF (374 kb)). Sorghum compositional components were statistically analyzed using a mixed model analysis of variance, and statistical differences among the sorghum varieties were identified and assessed (P <0.05). The biological relevance of any significant difference among sorghum varieties was assessed by determining the magnitude of difference between sorghum event Inzen and the unmodified control sorghum variety and the natural variation within the reference sorghum varieties grown in the trials, as well as those obtained from the published scientific literature (OECD, 2010).

No statistically significant differences were observed between sorghum event Inzen forage and the unmodified control sorghum variety for the proximates, CF, ADF, NDF, carbohydrates, calcium and phosphorus. All means of sorghum event Inzen forage were within the natural variation of the reference sorghum varieties. Statistically significant differences were observed between sorghum event Inzen grain and the unmodified control sorghum variety for protein and carbohydrates, however the mean values were within the range of the reference sorghum varieties and/or literature values (OECD 2010), and therefore the differences were not considered biologically relevant. No significant differences were observed between sorghum event Inzen grain and the unmodified control sorghum variety for fat, ash, CF, TDF, ADF, NDF, starch, calcium, phosphorus and vitamin B6. All means were within the range of values of the reference sorghum varieties.

Except for cysteine and serine, the other amino acids analyzed in sorghum event Inzen were statistically significantly elevated in grain samples compared to the unmodified control sorghum variety. However, the mean of the amino acids in sorghum event Inzen were within the range of values of the reference sorghum varieties grown in the trial and literature values (OECD 2010), therefore the small statistical differences were not considered to be biologically relevant from a feed safety perspective. Statistically significant differences were observed between sorghum event Inzen grain and the unmodified control sorghum variety for palmitic (C16:0), palmitoleic (C16:1), linolenic (C18:3) and eicosenoic (C20:1) fatty acids. Mean values for these fatty acid components were however within the natural variability shown for the reference sorghum varieties. Levels of two minor fatty acids (2% of total fatty acids): heptadecanoic acid (C17:0) and heptadecenoic acid (C17:1) in sorghum event Inzen were elevated slightly outside of the unmodified control sorghum variety and the reference sorghum varieties at all sites. The applicant noted that this observation was expected due to the genetic alteration in sorghum event Inzen in the ALS-encoding gene, which may increase the 2-ketobutyrate pool available for C17 fatty acid synthesis. Odd numbered carbon chain fatty acids such as C17:0 and C17:1 are widely distributed in nature and are components of foods and feeds (e.g oil of plant seeds) which are consumed in diets and are therefore expected to be readily metabolized to Krebs cycle intermediates that will in turn be used in energy production. No safety or nutritional concerns are expected as a result of the slight increase in exposure of C17:0 and C17:1 fatty acids in feeds from sorghum event Inzen. The concentrations of anti-nutrients (phytic acid and tannins) were similar in sorghum event Inzen grain compared to the unmodified control sorghum variety. All means were within the natural variation of the reference sorghum varieties.

Conclusion

The evidence provided by E.I. du Pont Canada Company supports the conclusion that the nutritional composition of sorghum event Inzen is comparable to reference sorghum varieties.

2. Potential Impact of Sorghum event Inzen 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 original source of the trait, wild sorghum (shattercane; Sorghum bicolor L.) displaying tolerance to ALS-inhibiting herbicides, was backcrossed into grain sorghum. The progeny lines of sorghum event Inzen after five generation of backcrossing were characterized with respect to tolerance to various sulfonylurea and imidazolinone herbicides due to the presence of two SNPs and resultant two amino acid substitutions in the acetolactate synthase (ALS), also known as acetohydroxy acid synthase (AHAS).

The assessment of sorghum event Inzen used the weight of evidence approach to evaluate the impact of the potential hazards of the modified protein ALS on the safety of feed ingredients derived from this event.

Modified Acetolactate Synthase (ALS)

The potential allergenicity and toxicity of the ALS protein to livestock were 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 original source of the trait, wild sorghum (shattercane; Sorghum bicolor L.), is not known to produce allergens and a bioinformatics evaluation of the modified ALS protein amino acid sequences in sorghum event Inzen confirmed the lack of relevant similarities between this protein and known allergens. Moreover, the backcrossing of wild sorghum with grain sorghum over multiple generations to develop sorghum event Inzen, reduced the presence of genetic material from wild sorghum other than the herbicide-tolerant trait. The weight of evidence thus indicates that the ALS protein is unlikely to be allergenic.

In terms of the potential toxicity to livestock, the modified ALS protein lack a mode of action to suggest that it is intrinsically toxic to livestock and a bioinformatics evaluation of the modified ALS protein amino acid sequences confirmed the lack of relevant similarities between this protein and known toxins. In addition, there is a history of safe use of source organism wild sorghum and the sulfonylurea and imidazolinone herbicides-tolerant trait, safe exposure to the ALS protein, and safe exposure to the similar one and/or two point mutations of the ALS protein. Further, the livestock exposure to the ALS protein from sorghum event Inzen is unexpected to be different from the reference sorghum varieties. The weight of evidence thus indicates that the ALS protein is unlikely to be toxic to livestock.

Conclusion

It was concluded, based on the evidence provided by E.I. du Pont Canada Company, that the modified ALS protein-based herbicide tolerance trait will not confer to sorghum event Inzen any characteristic that would raise concerns regarding the safety of sorghum event Inzen. Feed ingredient(s) from sorghum event Inzen are considered to meet present ingredient definitions for sorghum in the Feeds Regulations and as such are approved for use as livestock feed in Canada.

VI. New Information Requirements

If at any time, E. I. du Pont Canada Company 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 sorghum event Inzen or lines derived from it, E. I. du Pont Canada Company 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 sorghum event Inzen 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 sorghum event Inzen.

VII. Regulatory Decision

Based on the review of the data and information submitted by E. I. du Pont Canada Company 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 sorghum event Inzen does not present altered environmental risk when compared sorghum varieties that are currently grown in Canada.

Based on the review of the data and information submitted by E. I. du Pont Canada Company and input from other relevant scientific sources, the Animal Feed Division of the Animal Health Directorate, CFIA, has concluded that the novel ALS protein-based herbicide tolerance trait will not confer to sorghum event Inzen any characteristic that would raise concerns regarding the safety or nutrition of sorghum event Inzen. Livestock feeds derived from sorghum are currently listed in Schedule IV of the Feeds Regulations. Sorghum event Inzen has been found to be as safe as and as nutritious as currently and historically grown sorghum varieties. Sorghum event Inzen grain and its products are considered to meet present ingredient definitions.

Taking into account the conclusion of the environmental risk assessment and recognizing that incidental release into the environment could occur when this PNT is used as intended, unconfined release into the environment of sorghum event Inzen and of any lines derived from it is therefore authorized by the Plant Biosafety Office of the Plant Health and Biosecurity Directorate as of July 4, 2017 on a condition that no sale of seed takes place in Canada. This condition is being applied to ensure that the PNT is used as intended.

Taking into account livestock feed assessment, use as livestock feed of sorghum event Inzen and of any lines derived from it is authorized by the Animal Feed Division of the Animal Health Directorate as of July 4, 2017.

Authorizations of the sorghum lines derived from sorghum event Inzen are conditional on the following:

  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 sorghum 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 genes are expressed at levels similar to those of the authorized line.

Sorghum event Inzen is subject to the same phytosanitary import requirements as unmodified sorghum varieties. Sorghum event Inzen is required to meet the requirements of other Canadian legislation, including but not limited to, the requirements set out in the Food & 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 sorghum event Inzen.

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