Decision Document DD2014-101
Determination of the Safety of BASF Canada Inc.'s Canola (Brassica napus) Event CLB-1

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 (Dir94-08) - Assessment Criteria for Determining Environmental Safety of Plants with Novel Traits, its companion document BIO1994-09 - The Biology of Brassica napus L. (Canola/Rapeseed), 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 BASF Canada Inc. This information is in regard to the herbicide tolerant canola event CLB-1. The CFIA has determined that this plant with a novel trait (PNT) does not present altered environmental risk nor, as a novel feed, does it present livestock feed safety concerns when compared to canola 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 canola event CLB-1 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 February 14, 2014. Any canola lines derived from canola event CLB-1 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, and
  3. it is known based on characterization that these plants do not display any additional novel traits and are substantially equivalent to canola 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.

Canola event CLB-1 is subject to the same phytosanitary import requirements as unmodified canola varieties. Canola event CLB-1 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 safety 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.

February 14, 2014

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

  1. Brief Identification of the Modified Plant
  2. Background Information
  3. Description of the Novel Traits
    1. Development Method
    2. Tolerance to Imazamox and Imazapyr Herbicides
    3. Stable Integration into the Plant Genome
  4. Criteria for the Environmental Assessment
    1. Potential of Canola Event CLB-1 to Become a Weed of Agriculture or be Invasive of Natural Habitats
    2. Potential for Gene Flow from Canola Event CLB-1 to Sexually Compatible Plants Whose Hybrid Offspring May Become More Weedy or More Invasive
    3. Altered Plant Pest Potential of Canola Event CLB-1
    4. Potential Impact of Canola Event CLB-1 on Non-Target Organisms
    5. Potential Impact of Canola Event CLB-1 on Biodiversity
  5. Criteria for the Livestock Feed Assessment
    1. Potential Impact of Canola Event CLB-1 on Livestock Nutrition
    2. Potential Impact of Canola Event CLB-1 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: Canola event CLB-1
Applicant: BASF Canada Inc.
Plant Species: Canola (Brassica napus L.)
Novel Traits: Tolerance to imazamox and imazapyr herbicides
Trait Introduction Method: Site-directed mutagenesis
Intended Use of the Modified Plant: Canola event CLB-1 is intended to be grown for traditional canola human food and livestock feed uses. Canola event CLB-1 is not intended to be grown outside the normal production area for canola in Canada.

II. Background Information

BASF Canada Inc. has developed a canola (Brassica napus) event that is tolerant to the imidazolinone herbicides imazamox and imazapyr. Canola event CLB-1 was developed by BASF Canada Inc. using site-directed mutagenesis of the AHAS3 gene in B. napus. This gene encodes an acetohydroxyacid synthase (AHAS) enzyme, which is also referred to as an acetolactate synthase (ALS) enzyme. The herbicide tolerance trait in canola event CLB-1 is conferred by two point mutations, an alanine to threonine substitution at position 122 and a serine to asparagine substitution at position 653, in the AHAS3 gene. These mutations result in a modified AHAS3 enzyme carrying two amino acid substitutions which render the enzyme insensitive to imidazolinone herbicides, including imazamox and imazapyr.

BASF Canada Inc. has provided information on the identity of canola event CLB-1; a description of the breeding history; information on the modified gene, the resulting protein and its mode of action; and the stability of trait expression. 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. Information was provided for the evaluation of herbicide residues in the feed commodities derived from the crop, following the intended herbicide application.

Canola event CLB-1 was field tested in the United States (US) at three sites in 2009 and at two sites in 2010. The locations of these trials share similar environmental and agronomic conditions to canola production areas in Canada and were considered representative of major Canadian canola growing regions.

Agronomic characteristics of canola event CLB-1, such as seedling emergence, seedling vigor, days to first flowering, days to end of flowering, days to maturity, plant height, harvest moisture, grain yield, insect damage and disease severity, were compared to those of an unmodified control canola variety which shares the same genetic background as canola event CLB-1.

Nutritional components of canola event CLB-1 seed, such as moisture, protein, fat, ash, acid detergent fibre (ADF), neutral detergent fibre (NDF), total dietary fibre (TDF), amino acids, fatty acids, minerals, vitamins and anti-nutrients (phytic acid, trypsin inhibitor and glucosinolates), were compared with those of the unmodified control canola variety and conventional control canola 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 (Dir94-08) - Assessment Criteria for Determining Environmental Safety of Plants with Novel Traits. The PBRA Unit has considered:

  • the potential of canola event CLB-1 to become a weed of agriculture or to be invasive of natural habitats;
  • the potential for gene flow from canola event CLB-1 to sexually compatible plants whose hybrid offspring may become more weedy or more invasive;
  • the potential for canola event CLB-1 to become a plant pest;
  • the potential impact of canola event CLB-1 and its gene products on non-target organisms, including humans; and
  • the potential impact of canola event CLB-1 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 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 canola event CLB-1 and unmodified canola varieties relative to the safety and efficacy of feed ingredients derived from canola event CLB-1 for their intended purpose, including:

  • the potential impact of canola event CLB-1 on livestock nutrition; and
  • the potential impact of canola event CLB-1 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 canola event CLB-1 meet the definitions and requirements of feeds as listed in Schedule IV of the Feeds Regulations.

BASF Canada Inc. has provided the CFIA with a method for the detection and identification of canola event CLB-1.

III. Description of the Novel Trait

1. Development Method

Canola event CLB-1 was developed through sequential site-directed mutagenesis of the AHAS3 gene in canola cells. Mutated cells were selected on the basis of tolerance to imazapyr and regenerated to produce plants. Canola event CLB-1 was identified as a successful mutant based on molecular analyses, herbicide efficacy and agronomic evaluations and was thus chosen for further development.

2. Tolerance to Imazamox and Imazapyr Herbicides

Imidazolinone herbicides, including imazamox and imazapyr, are active against AHAS enzymes. AHAS enzymes are found in bacteria, certain other micro-organisms and plants. These enzymes catalyse the first step in the biosynthesis of the essential branched chain amino acids isoleucine, leucine and valine. Herbicide-induced AHAS inhibition results in a lethal decrease in protein synthesis. Unmodified B. napus is not tolerant to imidazolinone herbicides. Introduction of two point mutations into the AHAS3 gene in canola event CLB-1, resulting in an alanine to threonine substitution at position 122 and a serine to asparagine substitution at position 653 of the AHAS3 protein, confers commercial-level tolerance to the herbicides imazamox and imazapyr.

Each of the two point mutations introduced into canola event CLB-1 were individually assessed in previous CFIA safety assessments of BASF Canada Inc.'s Sunflower Line CLHA-PLUS and CL Sunflower Hybrid H4 (DD2010-80), Canola Quality Indian Mustard Event S006 (DD2008-73), Wheat Event BW7 ( DD2007-66), and Rice Events IMINTA 1 and IMINTA 4 (DD2006-62).

The canola event CLB-1 imidazolinone herbicide tolerance trait is under the control of the native AHAS3 promoter and is believed to be constitutively expressed. Sequencing of the sites of mutagenesis in the AHAS3 gene confirmed that the expected modification of the AHAS3 gene is present in canola event CLB-1.

Since the AHAS proteins are involved in the biosynthesis of branched chain amino acids, including isoleucine, leucine and valine, amino acid analysis was conducted on the canola event CLB-1 seed. The results indicated that the amino acid profile in canola event CLB-1 is similar to that in the unmodified control canola variety, therefore it was concluded that two point mutations introduced into the AHAS3 protein did not result in an altered amino acid profile in canola event CLB-1.

The potential allergenicity and toxicity of the modified AHAS3 protein to livestock and non-target organisms were evaluated. The weight of evidence indicates that the modified AHAS3 protein is unlikely to be allergenic. The source of the AHAS3 gene, B. napus, is not known to produce allergens, the modified AHAS3 protein amino acid sequence lacks relevant similarities to those of known allergens and was shown experimentally to be rapidly degraded by intestinal proteases and not to be heat stable. It was also concluded that the modified AHAS3 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 and because the modified AHAS3 protein amino acid sequence lacks relevant similarities to known toxins. For a more detailed discussion of the potential allergenicity and toxicity of the modified AHAS3 protein, see Section V, part 2: Potential Impact of Canola Event CLB-1 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 Integration into the Plant Genome

The two point mutations in the AHAS3 gene that are responsible for the imidazolinone herbicide tolerance trait in canola event CLB-1 were shown to be inherited in a Mendelian fashion across multiple generations. In addition, field trials of canola event CLB-1 treated with imazamox demonstrated consistent herbicide tolerance, confirming the stable inheritance of this trait.

IV. Criteria for the Environmental Assessment

1. Potential of Canola Event CLB-1 to Become a Weed of Agriculture or be Invasive of Natural Habitats

Canola (B. napus) possesses some of the characteristics that are common to weeds and invasive plants. It is an annual crop that may persist in unmanaged ecosystems without human intervention. There have been reports of B. napus becoming a weed of agriculture in North America and other parts of the world; however, it has not become an abundant or problematic weed in Canada, despite being cultivated in Canada for many years. B. napus plants can grow as volunteers in cultivated fields in the seasons following a B. napus crop, but they are usually eliminated by soil cultivation or the use of herbicides. According to the information provided by BASF Canada Inc., canola event CLB-1 was determined not to be significantly different from unmodified canola varieties in this respect.

The CFIA evaluated data submitted by BASF Canada Inc. on the reproductive biology and life history traits of canola event CLB-1. As previously mentioned, canola event CLB-1 was field tested in the US at three locations in 2009 and at two locations in 2010. It was determined that the US locations share similar environmental and agronomic conditions to the canola growing regions of Manitoba, Saskatchewan and Alberta and were considered to be representative of major Canadian canola growing regions. During the field trials, canola event CLB-1 was compared to the unmodified control canola variety. Phenotypic and agronomic traits were evaluated, covering a broad range of characteristics that encompass the entire life cycle of the canola plant. The traits included seedling emergence, seedling vigour, days to first flowering, days to end of flowering, days to maturity, plant height, harvest moisture, grain yield, insect damage and disease severity. Although instances of statistically significant differences were observed between canola event CLB-1 and the unmodified control canola variety for some traits in the individual-site analyses, there were no consistent trends in the data across locations that would indicate the differences were due to the genetic modification. Therefore, the statistical analysis of these observations showed no biologically meaningful differences between canola event CLB-1 and the unmodified control canola variety, and supports a conclusion of phenotypic and agronomic equivalence to currently grown canola varieties.

BASF Canada Inc. evaluated the germination of canola event CLB-1 under a warm temperature regime. No significant difference was detected between canola event CLB-1 and the unmodified control canola variety. Therefore the introduction of the novel trait did not impact germination of the canola seed.

The susceptibility of canola event CLB-1 to canola 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: Altered Plant Pest Potential of Canola Event CLB-1). No trend in increase or decrease of susceptibility to pests or pathogens was observed in canola event CLB-1 compared to the unmodified control canola variety.

No competitive advantage was conferred to plants of canola event CLB-1, other than that conferred by tolerance to imidazolinone herbicides, as the reproductive characteristics, growth characteristics and tolerance to abiotic and biotic stresses of canola event CLB-1 were comparable to those of the unmodified control canola variety. Tolerance to imidazolinone herbicides provides a competitive advantage only when these herbicides are used and will not, in and of itself, make an imidazolinone tolerant plant weedier or more invasive of natural habitats. Canola event CLB-1 plants growing as volunteers will not be controlled if imidazolinone herbicides are used as the only weed control tool. However, control of canola event CLB-1 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.

The novel trait has no intended or observed effects on weediness or invasiveness. The CFIA has therefore concluded that canola event CLB-1 has no altered weediness or invasiveness potential in Canada compared to currently grown canola 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 tolerant weed populations. In order to address these issues, an herbicide tolerance management plan which 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.

BASF Canada Inc. has submitted an herbicide tolerance management plan to the CFIA, which was determined to be satisfactory when evaluated by the PBRA Unit. BASF Canada will make this herbicide tolerance management plan readily available to growers and agriculture extension personnel, in both private and public sectors, to promote careful management practices for canola event CLB-1. BASF Canada will provide an efficient mechanism for growers to report agronomic problems to the company, which will facilitate the ongoing monitoring of canola event CLB-1. BASF Canada will monitor grower implementation to determine the effectiveness of the herbicide tolerance management plan and make any changes to the plan as appropriate.

2. Potential for Gene Flow from Canola Event CLB-1 to Sexually Compatible Plants Whose Hybrid Offspring May Become More Weedy or More Invasive

Successful interspecific and intergeneric crosses between B. napus and some related species have been reported in the scientific literature (see biology document BIO1994-09 - The Biology of Brassica napus L. (Canola/Rapeseed) for more information). However, many of these crosses have required extensive human intervention and the rates of natural hybridization between B. napus and weedy relatives resulting in fertile offspring appear to be very low. Sinapsis arvensis is considered the worst of the weedy relatives of B. napus in Western Canada. Hybrids between both species can be produced under field conditions, however at very low frequency. Additionally, backcrossing of the hybrids to S. arvensis failed to produce viable progeny. Therefore, the likelihood of introgression of traits from B. napus to S. arvensis appears to be very low. In crosses with other wild related species (i.e. Raphanus raphanistrum and Erucastrum gallicum), no viable hybrid seed was produced.

Stable gene transfer from B. napus is most likely with Brassica crops such as B. juncea and B. rapa. The introgression of the two point mutations from canola event CLB-1 into Brassica crops is of minimal concern as they are already present in commercial Brassica varieties such as Canola Quality Indian Mustard Event S006 (DD2008-73). Any hybrids resulting from outcrossing between canola event CLB-1 and B. rapa or B. juncea could be controlled by the use of herbicides other than imidazolinones or by mechanical means.

If imidazolinone tolerant individuals arose through interspecific or intergeneric hybridization, the novel trait would confer no competitive advantage to these plants unless challenged by imidazolinone herbicides. This would only occur in managed ecosystems where imidazolinone herbicides are used for weed control. As with imidazolinone tolerant canola event CLB-1 volunteers, these herbicide tolerant individuals, should they arise, could be controlled using mechanical means or herbicides other than imidazolinone herbicides. Hybrids, if they developed, could potentially result in the loss of imidazolinone herbicides as a tool to control these species. This, however, can be avoided by the use of sound crop management practices. BASF Canada's herbicide tolerance management plan for canola event CLB-1 contains recommendations to minimize and manage outcrossing to related species.

This information led the CFIA to conclude that gene flow from canola event CLB-1 to related species in Canada is possible but would not result in increased weediness or invasiveness of the resulting progeny.

3. Altered Plant Pest Potential of Canola Event CLB-1

Canola is not considered to be a plant pest in Canada and the imidazolinone herbicide tolerance trait introduced into canola event CLB-1 is unrelated to plant pest potential (e.g. the potential for the plant to harbour new or increased populations of pathogens or pests).

The susceptibility of canola event CLB-1 to canola pests and pathogens was evaluated in the field at the same locations as the agronomic characteristic studies. The stressors observed included flea beetles, blackleg and sclerotinia stem rot. The evaluations of canola event CLB-1 did not show any increase or decrease in susceptibility to these pests or pathogens compared to the unmodified control canola variety.

The CFIA has therefore concluded that canola event CLB-1 does not display any altered plant pest potential compared to currently grown canola varieties.

4. Potential Impact of Canola Event CLB-1 on Non-target Organisms

The imidazolinone herbicide tolerance trait introduced into canola event CLB-1 is unrelated to a potential impact on non-target organisms.

AHAS proteins are ubiquitous in plants and have a history of safe consumption by animals. Detailed characterization of the modified AHAS enzyme expressed in canola event CLB-1 led to the conclusion that this AHAS protein does not display any characteristics of a potential toxin or allergen (see Section III, part 2: Tolerance to Imazamox and Imazapyr Herbicides). In addition, other crops containing imidazolinone-tolerant AHAS proteins with the same amino-acid substitutions as in canola event CLB-1 include BASF Canada Inc.'s Sunflower Line CLHA-PLUS and CL Sunflower Hybrid H4 (DD2010-80), Canola Quality Indian Mustard Event S006 ( DD2008-73), Wheat Event BW7 (DD2007-66), and Rice Events IMINTA 1 and IMINTA 4 (DD2006-62). No adverse effects on non-target organisms have been associated with cultivation of these crops in Canada or elsewhere. Therefore no negative impacts resulting from exposure of organisms to the modified AHAS protein expressed in canola event CLB-1 are expected.

Composition analyses showed that the levels of key nutrients and anti-nutrients in grain from canola event CLB-1 are comparable to those in grain from conventional canola varieties (see Section V, part 1: Potential Impact of Canola Event CLB-1 on Livestock Nutrition). In addition, the protein profile in grain from canola event CLB-1 was found to be similar to that of conventional canola varieties, indicating that the mutagenesis process did not result in the unintended expression of new proteins or modified levels of proteins in CLB-1 canola grain, compared to conventional canola grain. Therefore, it is very unlikely that the introduction of the novel trait may have caused unintended changes to the composition of canola event CLB-1 tissues that would negatively impact organisms interacting with canola event CLB-1.

Collectively, these information elements indicate that the interactions between canola event CLB-1 and the populations of animals and microorganisms interacting with canola crops will be similar compared to currently grown canola varieties.

The CFIA has therefore determined that the unconfined release of canola event CLB-1 in Canada will not result in altered impacts on non-target organisms, including humans, compared to currently grown canola varieties.

5. Potential Impact of Canola Event CLB-1 on Biodiversity

Canola event CLB-1 expresses no novel phenotypic characteristics that would extend its range beyond the current geographic range of canola production in Canada. Canola event CLB-1 is unlikely to cause adverse effects on non-target organisms and does not display increased weediness, invasiveness or plant pest potential. Canola (B. napus) can outcross to B. rapa and B. juncea, and potentially to wild relatives, under natural conditions in Canada. However, the consequences of the transfer of the imidazolinone tolerance trait are minimal as the novel trait does not confer any selective advantage in the absence of the herbicide, and imidazolinone tolerant hybrids can be controlled by herbicides with other modes of action, or through mechanical means.

It is therefore unlikely that canola event CLB-1 will have any direct effects on biodiversity, in comparison to the effects that would be expected from the cultivation of the canola varieties that are currently grown in Canada.

Canola event CLB-1 has tolerance to imidazolinone herbicides. The use of these herbicides 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 which utilize these weed species. It must be noted however that the goal of reduction in weed biodiversity in agricultural fields is not unique to the use of PNTs, canola event CLB-1 or the cultivation of canola. It is therefore unlikely that canola event CLB-1 will have any indirect effects on biodiversity, in comparison to the effects that would be expected from cultivation of currently grown canola varieties.

The CFIA has concluded that the modified gene and its corresponding novel trait do not confer to canola event CLB-1 any characteristic that would result in unintended environmental effects following unconfined release. The CFIA has therefore concluded that the potential impact on biodiversity of canola event CLB-1 is unlikely to be different from that of the canola 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 canola event CLB-1, 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 canola event CLB-1 meet the definitions and requirements of feeds as listed in Schedule IV of the Feeds Regulations.

1. Potential Impact of Canola Event CLB-1 on Livestock Nutrition

Nutrient and Anti-nutrient Composition:

The nutritional equivalence of canola event CLB-1 (untreated and treated with imazamox herbicide) to the unmodified control canola variety and two conventional control canola (B. napus) varieties was assessed from three replicated field sites in the US during the 2009 growing season. At each site, seeds were planted in a randomized complete block design with three plots per canola line. Seed samples were collected upon harvest from each plot and stored under environmentally-controlled conditions, until compositional analysis was conducted. Seed samples were analysed for protein, crude fat, crude fibre, ash, acid detergent fibre (ADF), neutral detergent fibre (NDF), total dietary fibre (TDF), amino acids, fatty acids, minerals, vitamins and anti-nutrients (phytic acid, trypsin inhibitor and glucosinolates). Analysis of variance was used for statistical examination of the compositional data, and comparison of means was conducted at a 95% confidence level (P<0.05). Statistically significant differences observed between canola event CLB-1 and the unmodified control canola variety were assessed by considering the range of values observed for the conventional canola varieties included in the trials and those published in scientific literature (OECD 2011 - PDF (548 kb)).

No statistically significant differences were observed between canola event CLB-1 (treated and untreated) and the unmodified control canola variety for crude fat, crude fibre, protein, ash, ADF, NDF and TDF. Crude fibre, ADF and NDF were statistically significantly lower in canola event CLB-1(untreated) and the unmodified control canola variety than in the conventional control canola varieties; however, the fibre levels were within the range of published literature values (OECD 2011 - PDF (548 kb)). No statistically significant differences were observed between canola event CLB-1 (treated and untreated) and the unmodified control canola variety for the branched-chain amino acid (valine, leucine and isoleucine) levels, indicating that the genetic modification had no effect on the synthesis of the branched-chain amino acids. Levels of the essential amino acids (lysine, methionine, cystine and threonine) were not statistically significantly different between canola event CLB-1 (treated and untreated) and the unmodified control canola variety and were similar to those in the conventional control canola varieties. The levels of all other amino acids in canola event CLB-1 were within the range of those measured in the conventional control canola varieties. The level of erucic acid for most of the seed samples was below the limit of detection for this fatty acid (0.01%) and therefore was not statistically analysed. Except for lignoceric acid (C24:0), no statistically significant differences were observed between canola event CLB-1 (untreated) and the unmodified control canola variety for levels of the other fatty acids analysed. The level of lignoceric acid in canola event CLB-1 was within the values reported in the published literature (OECD 2011 - PDF (548 kb)). No statistically significant differences were observed between canola event CLB-1(untreated) and the unmodified control canola variety for levels of all minerals analysed. Statistically significant differences were observed between canola event CLB-1 (untreated) and the unmodified control canola variety for vitamin B6 content and also between canola event CLB-1(untreated) and the conventional control canola varieties for calcium, niacin, vitamin B6 and folic acid levels. The mean levels for these nutrients were, however, within the range of values reported in the published literature (OECD 2011 - PDF (548 kb)); therefore, the differences were not considered biologically relevant. There were no statistically significant differences in the levels of phytic acid, trypsin inhibitor and glucosinolates between canola event CLB-1 (untreated) and the unmodified control canola variety.

Conclusion:

It was concluded, based on the evidence provided by BASF Canada Inc., that the nutritional composition of canola event CLB-1 is similar to that of conventional canola (B. napus) varieties.

2. Potential Impact of Canola Event CLB-1 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

Canola event CLB-1 is tolerant to imidazolinone herbicides, including imazamox and imazapyr, due to the presence of two point mutations, A122T and S653N, in the AHAS3 gene. The assessment of canola event CLB-1 evaluated the impact of the following potential hazards relative to the safety of feed ingredients derived from this event:

  • The presence of the modified AHAS3 protein
  • The chemical pesticide residue profile

Modified AHAS3 protein

The potential allergenicity and toxicity of the modified AHAS3 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 AHAS3 gene, B. napus, is not known to produce allergens and a bioinformatics evaluation of the modified AHAS3 protein amino acid sequence confirmed the lack of relevant similarities between the modified AHAS3 protein and known allergens. Unlike many allergens, the modified AHAS3 protein was shown experimentally to be rapidly degraded by intestinal proteases and not to be heat stable. The weight of evidence thus indicates that the modified AHAS3 protein is unlikely to be allergenic.

In terms of its potential toxicity to livestock, the modified AHAS3 protein lacks a mode of action to suggest that it is intrinsically toxic to livestock and a bioinformatics evaluation of the modified AHAS3 protein amino acid sequence confirmed the lack of relevant similarities between the modified AHAS3 protein and known toxins. This information indicates that the modified AHAS3 protein is unlikely to be toxic to livestock.

The livestock exposure to the modified AHAS3 protein is expected to be negligible as AHAS proteins are not expressed at high levels in wild type canola, and there were no exogenous promoters introduced nor changes to the endogenous promoter in canola event CLB-1 which might have resulted in altered protein expression. In addition, the protein is rapidly degraded under conditions which simulate the mammalian digestive tract and is unstable under heating conditions expected to be encountered during processing of some canola products.

Chemical pesticide residue profile

The safety of herbicide residues and metabolites in canola event CLB-1, following application of herbicides, was also evaluated as part of the feed safety assessment It was determined that that potential imazamox and imazapyr residues in livestock commodities: grain canola, its byproducts and canola oil from canola event CLB-1, would not present levels of concern to livestock, nor humans, via the potential transfer into foods of animal origin.

Conclusion:

It was concluded, based on the evidence provided by BASF Canada Inc., that the novel AHAS3 protein-based herbicide tolerance trait will not confer to canola event CLB-1 any characteristic that would raise concerns regarding the safety of canola event CLB-1. Feed ingredients derived from canola event CLB-1 are considered to meet present ingredient definitions for canola.

VI. New Information Requirements

If at any time, BASF Canada Inc. becomes aware of any new information regarding risk to the environment livestock or human health, which could result from release or livestock feed use of canola event CLB-1 or lines derived from it, BASF 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 canola event CLB-1 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 canola event CLB-1.

VII. Regulatory Decision

Based on the review of the data and information submitted by BASF 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 canola event CLB-1 does not present altered environmental risk when compared to canola varieties that are currently grown in Canada.

Based on the review of the data and information submitted by BASF Canada Inc. and input from other relevant scientific sources, the Animal Feed Division of the Animal Health Directorate, CFIA, has concluded that the novel modified AHAS3 protein-based herbicide tolerance trait will not confer to canola event CLB-1 any characteristic that would raise concerns regarding the safety or nutritional composition of canola event CLB-1. Grain canola, its byproducts and canola oil are currently listed in Schedule IV of the Feeds Regulations and are, therefore approved for use in livestock feeds in Canada. Canola event CLB-1 has been found to be as safe as and as nutritious as currently and historically grown canola varieties. Canola event CLB-1 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 canola event CLB-1 is therefore authorized by the Plant Biosafety Office of the Plant Health and Biosecurity Directorate and the Animal Feed Division of the Animal Health Directorate as of jFebruary 14, 2014. Any canola lines derived from canola event CLB-1 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, and (iii) it is known based on characterization that these plants do not display any additional novel traits and are substantially equivalent to canola 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.

Canola event CLB-1 is subject to the same phytosanitary import requirements as unmodified canola varieties. Canola event CLB-1 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 canola event CLB-1.

Date modified: