Authorized as of December 29, 2023
The Canadian Food Inspection Agency (CFIA) has evaluated information submitted by Bayer CropScience Inc. concerning the herbicide tolerant sugar beet event KWS20-1, which was co-developed with KWS SAAT SE & Co. KGaA. CFIA has determined that sugar beet event KWS20-1 does not present an altered environmental or livestock feed risk when compared to sugar beet varieties currently grown and permitted to be used in Canada. Sugar beet event KWS20-1 is therefore authorized for unconfined release and livestock feed use as of December 29, 2023, subject to the provisions outlined in this decision document.
On this page
- 1. Brief identification of the modified plant
- 2. Background information
- 3. Description of the novel traits
- 4. Criteria for the environmental assessment
- 5. Criteria for the livestock feed assessment
- 6. New information requirements
- 7. Regulatory decision
- 8. Contact us
- 9. References
1. Brief identification of the modified plant
Designation of the modified plant: Sugar beet event KWS20-1
Applicant: Bayer CropScience Inc.
Plant species: Sugar beet (Beta vulgaris L.)
Novel trait: Tolerance to dicamba, glufosinate, and glyphosate herbicides
Trait introduction method: Agrobacterium-mediated transformation
Intended end use of the modified plant: Traditional sugar beet uses as human food and livestock feed
Intended area of cultivation: Intended to be grown within the normal production area for sugar beet in Canada
2. Background information
Bayer CropScience Inc. and KWS SAAT SE & Co. KGaA have developed a sugar beet event that is tolerant to dicamba, glufosinate and glyphosate herbicides.
Sugar beet event KWS20-1 was developed using Agrobacterium-mediated transformation, resulting in the introduction of a phosphinothricin N-acetyltransferase (pat) gene, a dicamba mono-oxygenase (dmo) gene, a 5-enolpyruvylshikimate-3-phosphate synthase (cp4 epsps) gene, and associated regulatory elements.
Bayer CropScience Inc. provided:
- the identity of sugar beet event KWS20-1
- a detailed description of the introduced genetic elements and proteins encoded by these genetic elements
- information about how sugar beet event KWS20-1 compares to other sugar beet varieties in terms of its environmental safety
- information about how sugar beet event KWS20-1 compares to other sugar beet varieties in terms of its nutrition and safety as an animal feed
The CFIA has reviewed the above information, in light of the Assessment criteria for determining environmental safety of plants with novel traits (Directive 94-08). The CFIA has considered:
- the potential for sugar beet event KWS20-1 to become a weed of agriculture or to be invasive of natural habitats
- the potential for gene flow from sugar beet event KWS20-1 to sexually compatible plants whose hybrid offspring may become more weedy or more invasive
- the potential for sugar beet event KWS20-1 to become a plant pest
- the potential impact of sugar beet event KWS20-1 and its gene products on non-target organisms, including humans
- the potential impact of sugar beet event KWS20-1 on biodiversity
The CFIA has also reviewed the above information with respect to the Guidelines for the Assessment of Novel Feeds: Plant Sources (RG-1 Regulatory Guidance: Feed Registration Procedures and Labelling Standards).
The CFIA has considered both intended and unintended effects and similarities and differences between sugar beet event KWS20-1 and unmodified sugar beet varieties relative to the safety and nutrition of feed ingredients derived from sugar beet event KWS20-1 for their intended purpose, including:
- the potential impact of sugar beet event KWS20-1 on livestock nutrition
- the potential impact of sugar beet event KWS20-1 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 CFIA has also considered whether feeds derived from sugar beet event KWS20-1 meet the definitions and requirements of feeds as listed in Schedule IV of the Feeds Regulations.
3. Description of the novel traits
3.1. Development method
Sugar beet event KWS20-1 was developed through Agrobacterium-mediated transformation of the breeding line 04E05B1DH05 using a single plasmid that included a single transfer DNA (T-DNA). The T-DNA contained 3 gene cassettes for dmo, pat, and cp4 epsps conferring tolerance todicamba, glufosinate, and glyphosate herbicides, respectively. Transformed plant cells were selected based on successful growth on selection medium containing glufosinate (DL-phosphinothricin) and then placed in media conducive to root development. Rooted plantlets with normal phenotypic characteristics and which passed the advancement criteria (desirable T-DNA insert characteristics) were selected and transferred to soil for growth and further assessment. The sugar beet event KWS20-1 was identified as a candidate for commercial development based on herbicide tolerance and agronomic evaluations.
3.2. Dicamba herbicide tolerance
Dicamba is a group 4 herbicide that mimics indole-3-acetic acid, a natural plant hormone of the auxin class. Dicamba application to susceptible plants causes rapid and uncontrolled growth of the stems, petioles and leaves, leading to the destruction of vascular tissues and eventually plant death. Dicamba is used for broadleaf weed control on grain crops, pastures, and non-crop areas.
Introduction of the dmo gene into sugar beet event KWS20-1 confers commercial-level tolerance to the herbicide dicamba. The dmo gene encodes the protein dicamba mono-oxygenase (DMO), which converts dicamba to non-herbicidal 3,6-dichlorosalicylic acid. The dmo gene was derived from Stenotrophomonas maltophilia and optimized for expression in sugar beet. Stenotrophomonas maltophilia is a gram-negative bacterium commonly present in soil, plants and aquatic environments.
The mature DMO protein in sugar beet event KWS20-1 is identical to the native DMO protein, except for an insertion of a single amino acid at position 2 from the N-terminus, which is not expected to change the functional activity of the protein. This insertion at position 2 is present on several other previously approved DMO events (such as cotton MON88701). The immature DMO in sugar beet event KWS20-1 contains a 27 amino acid chloroplast transit peptide (CTP). As the CTP is not part of the mature protein, it is not expected to alter the function of the mature protein.
The dmo gene in sugar beet event KWS20-1 is linked to a constitutive promoter. Tissue samples of sugar beet event KWS20-1 were collected at various plant growth stages from 5 field trial sites in the USA.
| Growth stage | Tissue | Micro-grams protein per gram dry weight tissue (µg/g dwt) |
|---|---|---|
| Leaf development: 7 to 8 leaves unfolded (BBCHTable note 1 17 to 18) | Leaf | 95 to 200 |
| Root | 22 to 34 | |
| Rosette growth: Leaves cover 20 to 90% of ground (BBCHTable note 1 32 to 39) | Leaf | 83 to 160 |
| Root | 11 to 34 | |
| Development of harvestable vegetative plant parts: Beet root has reached harvestable size (BBCHTable note 1 49) | Tops (leaves above ground) | 26 to 88 |
| Root | 7.6 to 17 |
The identity and integrity of the DMO protein produced in sugar beet event KWS20-1 was confirmed by molecular weight, immunoreactivity, nanoscale liquid chromatography coupled to tandem mass spectrometry (nano LC-MS/MS), and N-terminal sequence.
The potential allergenicity and toxicity of the DMO protein were evaluated. The weight of evidence indicates that this protein is unlikely to be allergenic, based on the following information:
- The source of the dmo gene, S. maltophilia, is not commonly associated with allergenicity
- Bioinformatics evaluations of the DMO amino acid sequence confirmed the lack of relevant similarities to known allergens
- Unlike many allergenic proteins, which tend to resist digestion, the DMO protein is rapidly degraded in simulated gastric fluid, and is not heat-stable (shown experimentally in DD2014-104)
It was also concluded that the DMO 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; and
- bioinformatics evaluations of the DMO amino acid sequence confirmed the lack of relevant similarities to known toxins.
For a more detailed discussion of the potential allergenicity and toxicity of the DMO protein, see Potential impact of sugar beet event KWS20-1 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.
3.3. Glufosinate herbicide tolerance
Glufosinate herbicide inhibits the plant protein glutamine synthetase. Inhibiting glutamine synthetase results in reduced glutamine synthesis and the accumulation of lethal levels of ammonia in susceptible plants. Ammonia is produced by plants as a result of normal metabolic processes, but elevated levels of ammonia can interfere with essential plant processes, like photosynthesis, and lead to plant death.
Introduction of the pat gene into sugar beet event KWS20-1 confers commercial-level tolerance to the herbicide glufosinate. The pat gene encodes the protein phosphinothricin N-acetyltransferase (PAT), which acetylates the primary amino group of glufosinate, making the herbicide inactive. The pat gene was derived from Streptomyces viridochromogenes, a gram-positive soil bacterium, and optimized for expression in sugar beet.
The pat gene in sugar beet event KWS20-1 is linked to a constitutive promoter. Tissue samples of sugar beet event KWS20-1 were collected at various plant growth stages from 5 field trial sites in the USA.
| Growth stage | Tissue | Micro-grams protein per gram dry weight tissue (µg/g dwt) |
|---|---|---|
| Leaf development: 7 to 8 leaves unfolded (BBCHTable note 1 17 to 18) | Leaf | 16 to 36 |
| Root | 0.13 to 0.41 | |
| Rosette growth: Leaves cover 20 to 90% of ground (BBCHTable note 1 32 to 39) | Leaf | 9.4 to 33 |
| Root | 0.016 to 0.049 | |
| Development of harvestable vegetative plant parts: Beet root has reached harvestable size (BBCHTable note 1 49) | Tops (leaves above ground) | 2.6 to 8.3 |
| Root | <LOQTable note 2 |
The identity and integrity of the PAT protein produced in sugar beet event KWS20-1 was confirmed by molecular weight, immunoreactivity and nano LC-MS/MS.
The lack of potential toxicity and allergenicity of PAT protein has previously been establishedFootnote 1. Updated bioinformatics evaluations of the PAT amino acid sequence were submitted in the current application and confirmed the lack of relevant similarities to known toxins and allergens.
For a more detailed discussion of the potential allergenicity and toxicity of the PAT protein, see Potential impact of sugar beet event KWS20-1 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.
3.4. Glyphosate herbicide tolerance
The herbicide glyphosate inhibits the 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) protein in plants which is part of the shikimic acid pathway essential for the production of the aromatic amino acids. The inhibition of EPSPS ultimately leads to growth suppression or death of the plant.
Sugar beet event KWS20-1 was developed to be tolerant to the herbicide glyphosate by incorporation of the cp4 epsps gene from Agrobacterium sp. strain CP4. The cp4 epsps gene encodes the protein 5-enolpyruvylshikimate-3-phosphate synthase (CP4 EPSPS), which has a reduced affinity for glyphosate and continues to function in presence of glyphosate. Thus, the sugar beet event KWS20-1, which expresses the CP4 EPSPS protein, is tolerant to glyphosate.
The cp4 epsps gene was optimized for expression in sugar beet and is linked to a constitutive promoter. Tissue samples of sugar beet event KWS20-1 were collected at various plant growth stages from 5 field trial sites in the USA.
| Growth stage | Tissue | Micro-grams protein per gram dry weight tissue (µg/g dwt) |
|---|---|---|
| Leaf development: 7 to 8 leaves unfolded (BBCHTable note 1 17 to 18) | Leaf | 320 to 850 |
| Root | 270 to 680 | |
| Rosette growth: Leaves cover 20 to 90% of ground (BBCHTable note 1 32 to 39) | Leaf | 370 to 790 |
| Root | 140 to 420 | |
| Development of harvestable vegetative plant parts: Beet root has reached harvestable size (BBCHTable note 1 49) | Tops (leaves above ground) | 230 to 400 |
| Root | 68 to 150 |
The identity and integrity of the CP4 EPSPS protein produced in sugar beet event KWS20-1 was confirmed by molecular weight, immunoreactivity, and nano LC-MS/MS.
The lack of potential allergenicity and toxicity of the CP4 EPSPS protein has previously been establishedFootnote 2. Updated bioinformatics evaluations of the CP4 EPSPS amino acid sequence were submitted in this application and confirmed the lack of relevant similarities to known toxins and allergens.
For a more detailed discussion of the potential allergenicity and toxicity of the CP4 EPSPS protein, see Potential impact of sugar beet event KWS20-1 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.
3.5. Stable integration into the plant genome
Junction sequence analyses and directed sequencing demonstrated that sugar beet event KWS20-1 contains a single intact copy of the T-DNA with gene cassettes encoding the PAT, DMO, and CP4 EPSPS proteins. No additional elements, including intact or partial T-DNA fragments or plasmid backbone sequences, linked or unlinked to the intact insert, were detected in sugar beet event KWS20-1.
The stability of the inserted DNA was demonstrated by Southern blot across 3 generations in the breeding history of sugar beet event KWS20-1. The inheritance pattern of the insert was evaluated by genotypic analyses across 3 segregating generations of sugar beet event KWS20-1. Kompetitive Allele-Specific (KASP) PCR analysis showed that the insert is stably inherited and segregates according to the Mendelian rules of inheritance for a single genetic locus.
4. Criteria for the environmental assessment
The CFIA used information on the biology of sugar beet and conclusions from previous assessments of plants tolerant to dicamba, glufosinate, or glyphosate to inform the environmental assessment of sugar beet event KWS20-1, as described in the following sections.
Potential of sugar beet event KWS201-1 to become a weed of agriculture or be invasive of natural habitats
As indicated in Biology Document BIO2023-01, "The biology of Beta vulgaris L.", sugar beet does not invade unmanaged habitats in Canada. There is no evidence that sugar beet behaves as a weed in Canada. In Canada, sugar beet does not survive outside of cultivation for significant periods of time due to cold sensitivity and poor competitiveness.
Since 1995, the CFIA has reviewed agronomic fields trials conducted on various crop species with novel herbicide tolerances. These results show that the introduction of glyphosate, dicamba, or glufosinate tolerance mediated by the expression of CP4 EPSPS, DMO, and PAT proteins respectively, does not modify the reproductive biology and life history traits of a plant.
Cultivated sugar beet is a biennial plant that produces flowers and set seeds in the second year. In Canada, sugar beet is grown as an annual crop. In rare occasions and under specific circumstances, sugar beet plants can bolt and flower the first year. Any seeds or roots left after harvest are typically killed by frost and do not survive the winter conditions found in Canada's sugar beet production regions. If any sugar beet event KWS20-1 plants were to grow as volunteers, they would not be controlled by glyphosate, dicamba, and glufosinate herbicides. However, control of sugar beet event KWS20-1 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 CFIA considers the changes in usual agronomic practices that may arise from volunteer plants with novel herbicide tolerances. To address this issue, a herbicide tolerance management plan which includes sustainable volunteer management strategies should be implemented. The applicants submitted an herbicide tolerance management plan to the CFIA, which was determined to be satisfactory when evaluated.
The CFIA has therefore concluded that sugar beet event KWS20-1 has no altered weediness potential in Canada compared to currently grown sugar beet varieties, when a herbicide tolerance management plan is implemented.
Potential for gene flow from sugar beet event KWS20-1 to sexually compatible plants whose hybrid offspring may become more weedy or more invasive
As indicated in Biology Document BIO2023-01, "The biology of Beta vulgaris L." there are no species naturally occurring in Canada that are sexually compatible with B. vulgaris.
There are no wild populations of sugar beet in Canada. In addition, cultivated sugar beet, a biennial species, rarely sets flower in Canada as remaining roots left in the field after harvest are typically killed by frost. Therefore, the potential for gene flow from sugar beet event KWS20-1 to other sugar beet plants or related species is negligible in Canada.
The CFIA has therefore concluded that gene flow from sugar beet event KWS20-1 to sexually compatible plants is negligible in Canada.
Potential for sugar beet event KWS20-1 to become a plant pest
Sugar beet is not considered to be a plant pest in Canada and the glyphosate, dicamba, and glufosinate herbicide tolerance traits introduced into sugar beet event KWS20-1 are unrelated to plant pest potential (that is, the potential for the plant to harbour new or increased populations of pathogens or pests).
CFIA has therefore concluded that sugar beet event KWS20-1 are not expected to display any altered plant pest potential compared to sugar beet varieties that are currently grown in Canada.
Potential impact of sugar beet event KWS20-1 on non-target organisms, including humans
The CP4 EPSPS, DMO, and PAT proteins are not known toxins or allergens (see Potential impact of sugar beet event KWS20-1 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) and are commonly found in a wide variety of plants and micro-organisms with a history of safe use.
Based on the above, the CFIA has determined that the unconfined release of sugar beet event KWS20-1 in Canada will not result in altered impacts on non-target organisms, including humans, when compared to sugar beet varieties that are currently grown in Canada.
Potential impact of sugar beet event KWS20-1 on biodiversity
Sugar beet event KWS20-1 expresses no novel phenotypic characteristics that would extend its range beyond the current geographic range of sugar beet production in Canada. Sugar beet event KWS20-1 is unlikely to cause adverse effects on non-target organisms and is not expected to display increased invasiveness or plant pest potential compared to sugar beet varieties grown in Canada, or increased weediness when a herbicide tolerance plan is implemented. Gene flow from sugar beet event KWS20-1 to sexually compatible plants is negligible in Canada.
Sugar beet event KWS20-1 has tolerance to glyphosate, dicamba, and glufosinate 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, sugar beet event KWS20-1 or the cultivation of sugar beet. It is therefore unlikely that sugar beet event KWS20-1 will have any indirect effects on biodiversity, in comparison to the effects that would be expected from cultivation of currently grown sugar beet varieties.
The CFIA considers the potential that continued application of the same herbicides in subsequent rotations may lead to increased selection pressure for herbicide tolerant weed populations. To address this issue, an herbicide tolerance management plan which includes integrated weed management strategies should be implemented. This plan may include a recommendation to rotate or combine weed control products with alternate modes of action and to employ other weed control practices. The herbicide tolerance management plan for sugar beet event KWS20-1 contains recommendations to minimize and manage the development of herbicide resistant weed populations. The herbicide tolerance management plan was determined to be satisfactory when evaluated.
The CFIA has therefore concluded that the potential impact on biodiversity of sugar beet event KWS20-1 is unlikely to be different from that of the sugar beet varieties that are currently grown in Canada, when a herbicide tolerance management plan is implemented.
5. Criteria for the livestock feed assessment
The CFIA considered the safety and efficacy of feed ingredients derived from KWS20-1 sugar beet, including nutrient and anti-nutrient profiles; 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 KWS20-1 sugar beet meet the definitions and requirements of feeds as listed in Schedule IV of the Feeds Regulations.
Potential impact of sugar beet event KWS20-1 on livestock nutrition
A field trial comparing KWS20-1 and a near-isogenic control (derived from breeding line 04E05B1DH05, ID 11511557) was conducted during the 2020 growing season at five field sites in the United States representative of commercial growing conditions (Idaho, Michigan, Minnesota and North Dakota). The trial was conducted using a randomized complete block design with four replicate blocks at each site. Each block contained KWS20-1 sugar beet and the near-isogenic control. At each site, 4 reference sugar beet varieties were grown concurrently for a total of 14 unique reference varieties.
Sugar beet roots harvested from KWS20-1, the near-isogenic control and the reference varieties were analyzed for proximates, sucrose, fibre, minerals and oleanic acid. Sugar beet tops harvested from KWS20-1, the near-isogenic control and the reference varieties were analyzed for proximates and crude fibre. Compositional data from KWS20-1 and the control were statistically analyzed using a mixed model analysis of variance. The biological relevance of significant (P<0.05) differences between KWS20-1 and the control was assessed within the range of the concurrently grown reference varieties and the published scientific literature.
Statistically significant (P<0.05) differences were observed between KWS20-1 sugar beet and the near-isogenic control for eight components (lysine, proline, serine, threonine, total fat, ash, phosphorus and potassium). The biological relevance of these differences was assessed in comparison to the natural variation in sugar beet from the concurrently grown reference varieties and the published literature. All nutrient and anti-nutrient levels were within the range of conventional sugar beet and therefore the observed differences are not considered biologically relevant. These differences in nutrient composition would have little impact on the total diet in normal livestock feeding practises, and little impact on the composition of co-products such as beet pulp or molasses.
Conclusion
Based on the data provided by Bayer CropScience Inc., the nutritional composition of KWS20-1 herbicide tolerant sugar beet is similar to that of conventional sugar beet varieties. Sugar beet roots, tops and co-products derived from KWS20-1 herbicide tolerant sugar beet are considered to meet present ingredient definitions for sugar beet in Schedule IV of the Feeds Regulations.
Potential impact of sugar beet event KWS20-1 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
For each of the novel proteins, a weight-of-evidence approach was used to evaluate the risks associated with:
- livestock consuming feed ingredients from KWS20-1 sugar beet
- humans consuming foods of animal origin derived from those livestock
- workers/bystanders exposed to the feed ingredients from sugar beet event KWS20-1
CP4 EPSPS protein
The potential allergenicity and potential toxicity of the CP4 EPSPS protein were evaluated. Concerning its potential allergenicity, the host organism source, sugar beet, is not considered to be a common allergenic food. The source of the cp4 epsps, Agrobacterium sp, is not commonly associated with allergenicity. The amino acid sequence of CP4 EPSPS in the KWS20-1 sugar beet is nearly identical to the amino acids of the naturally corresponding protein and identical to the previously assessed and authorized CP4 EPSPS protein in the MON87411 corn. A bioinformatics evaluation of the CP4 EPSPS protein'samino acid sequence confirmed the lack of relevant similarities between this protein and known allergens. Bridging data submitted in support of the CP4 EPSPS protein safety in the KWS20-1 sugar beet demonstrated that this protein is rapidly degraded under conditions simulating the mammalian digestive tract. The weight of evidence thus indicates that the CP4 EPSPSprotein is unlikely to be allergenic.
In terms of the potential toxicity, the CP4 EPSPS protein lacks a mode of action to suggest that it is intrinsically toxic. The source of the cp4 epsps, Agrobacterium sp, is not commonly associated with toxicity. A bioinformatics evaluation of its protein amino acid sequence confirmed the lack of relevant similarities between the CP4 EPSPS protein and known toxins. Livestock exposure to the CP4 EPSPS proteinis expected to be low, as this protein is expressed at levels of 430 µg/g dry weight (mean maximum) in root and of 590 µg/g dry weight (mean maximum) in the leaf of KWS20-1 sugar beet. Bridging data submitted in support of the CP4 EPSPS protein safety in the KWS20-1 sugar beet demonstrated that this protein is rapidly degraded under conditions which simulate the mammalian digestive tract. The weight of evidence thus indicates that the CP4 EPSPS protein is unlikely to be toxic.
Therefore, the CP4 EPSPS protein in the KWS20-1 sugar beetis unlikely to pose a risk to livestock, humans, and workers/bystanders.
DMO protein
The potential mammalian allergenicity and potential toxicity of the DMO protein were evaluated. Concerning its potential allergenicity, the source of the dmo gene, Stenotrophomonas maltophilia, is not commonly associated with allergenicity. The amino acid sequence of the mature DMO in the KWS20-1 sugar beet is identical to the previously assessed and authorized the mature DMO protein in the MON87419 corn and the MON87429 corn. The 27 residual amino acids from the chloroplast transit peptide (CTP) of the DMO in the KWS20-1 sugar beet are identical to the 27 residual CTP amino acids present of the DMO of the previously assessed and authorized MON87708 soybean. A bioinformatics evaluation of the DMO protein amino acid sequence confirmed the lack of relevant similarities between this protein and known allergens. Bridging data submitted in support of the DMO protein safety in the KWS20-1 sugar beet demonstrated this protein is rapidly degraded under conditions simulating the mammalian digestive tract. The weight of evidence thus indicates that the DMO protein is unlikely to be allergenic.
In terms of the potential toxicity, the DMO protein lacks a mode of action to suggest that it is intrinsically toxic. The source of the dmo gene, Stenotrophomonas maltophilia, is not commonly associated with toxicity. A bioinformatics evaluation of the DMO protein amino acid sequence confirmed the lack of relevant similarities between the DMO proteinand known toxins. Additionally, the livestock exposure to the DMO protein is expected to be very low, as this protein is expressed at low levels in the KWS20-1 sugar beet root (maximum 34 µg/g dry weight) and leaf (maximum 200 µg/g dry weight). Bridging data submitted in support of the DMO proteinsafety demonstrated that this protein is rapidly degraded under conditions simulating the mammalian digestive tract. The weight of evidence thus indicates that the DMO proteinis unlikely to be toxic.
Therefore, the DMO protein in the KWS20-1 sugar beet is unlikely to pose a risk to livestock, humans, and workers/bystanders.
PAT protein
The potential allergenicity and potential toxicity of the PAT protein were evaluated. Concerning its potential allergenicity, the source of the pat gene, Streptomyces viridochromogenes, is not commonly associated with allergenicity. The amino acid sequence of the PAT protein produced in the KWS20-1 sugar beet is identical to those of the PAT protein in previously assessed and authorized plants that are currently in commercial use. A bioinformatics evaluation of the PATproteinamino acid sequences confirmed the lack of relevant similarities between this protein and known allergens. Bridging data submitted in support of the PAT protein safety demonstrated this protein is rapidly degraded under conditions simulating the mammalian digestive tract. The weight of evidence thus indicates that the PAT protein is unlikely to be allergenic.
In terms of the potential toxicity, the PAT protein lacks a mode of action to suggest that it is intrinsically toxic. The source of the pat gene, Streptomyces viridochromogenes, is not commonly associated with toxicity. The amino acid sequence of the PAT protein produced in the KWS20-1 sugar beet is identical to that of the PAT protein in previously assessed and authorized events. A bioinformatics evaluation of the PAT proteinamino acid sequence confirmed the lack of relevant similarities between this protein and known toxins. Additionally, the livestock exposure to the PAT protein is expected to be negligible, as this protein is expressed at very low levels in the KWS20-1 sugar beet root (maximum 0.41 µg/g dry weight) and leaf (maximum 36 µg/g dry weight). Bridging data submitted in support of the PAT proteinsafety demonstrated this protein is rapidly degraded under conditions which simulate the mammalian digestive tract. The weight of evidence thus indicates that the PAT proteinis unlikely to be toxic.
Therefore, the PAT protein in the KWS20-1 sugar beet is unlikely to pose a risk to livestock, humans, and workers/bystanders.
Conclusion
Based on the evidence provided by Bayer CropScience Inc., it is concluded that the KWS20-1 sugar beet is unlikely to pose a risk to livestock consuming feed ingredients from the KWS20-1 sugar beet, to humans consuming foods of animal origin derived from those livestock, and to workers/bystanders exposed to the feed ingredients from this event.
6. New information requirements
If at any time, the applicants 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 sugar beet event KWS20-1 or lines derived therefrom, the applicants are 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 sugar beet event KWS20-1 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 sugar beet event KWS20-1.
7. Regulatory decision
Environmental release
Based on the review of the data and information submitted by Bayer CropScience Inc. and input from other relevant scientific sources, the CFIA has concluded that the unconfined environmental release of sugar beet event KWS20-1 does not present altered environmental risk when compared to sugar beet varieties that are currently grown in Canada when a suitable herbicide tolerance management plan is implemented.
Bayer CropScience Inc.'s herbicide tolerance management plan was determined to be satisfactory when evaluated by the CFIA. As outlined in the plan, Bayer CropScience Inc. 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 sugar beet event KWS20-1. Bayer CropScience Inc will provide an efficient mechanism for growers to report agronomic problems to the company, which will facilitate the ongoing monitoring of sugar beet event KWS20-1. Bayer CropScience Inc. will monitor grower implementation to determine the effectiveness of the herbicide tolerance management plan and make any changes to the plan as appropriate.
Unconfined release into the environment of sugar beet event KWS20-1 is therefore authorized by the CFIA as of December 29, 2023.
Livestock feed use
Based on the review of the data and information submitted by the applicant, along with input from other relevant scientific sources, the CFIA has concluded that the herbicide-tolerant traits will not confer any characteristics to sugar beet event KWS20-1 that would raise concerns regarding its safety or nutritional value. Livestock feeds derived from sugar beet are currently listed in Schedule IV of the Feeds Regulations. Sugar beet event KWS20-1 has been determined to be as safe as and as nutritious as currently and historically grown sugar beet varieties. Sugar beet event KWS20-1 and its products are considered to meet the present ingredient definitions.
Use as livestock feed of sugar beet event KWS20-1 is therefore authorized by the CFIA as of December 29, 2023.
Lines derived from the authorized line
Any sugar beet lines derived from sugar beet event KWS20-1 may also be released into the environment and used as livestock feed, provided that:
- no inter-specific crosses are performed
- the intended uses are similar
- it is known based on characterization that these plants do not display any additional novel traits and are substantially equivalent to sugar beet 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
- the novel genes are expressed at a level similar to that of the authorized line
Cultivation of plants derived from sugar beet event KWS20-1 is subject to herbicide tolerance management requirements.
Other regulatory requirements
Sugar beet event KWS20-1 is subject to the same phytosanitary import requirements as unmodified sugar beet varieties. Sugar beet event KWS20-1 is required to meet the requirements of other Canadian legislation as applicable, including but not limited to, the Food & Drugs Act and the Pest Control Products Act.
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 assessment of novel foods by Health Canada, have been addressed separately from this review. Refer to Health Canada's Decisions on Novel Foods for a description of the food safety assessment of sugar beet event KWS20-1.
8. Contact us
For more information on this decision, please contact the CFIA's Plant Biosafety Office or Animal Feed Program.