Decision Document DD2017-120
Determination of the Safety of J.R. Simplot Company's Potato (Solanum tuberosum (L.)) Events GEN2-W8, GEN2-X17 and GEN2-Y9

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 The Biology of Solanum tuberosum (L.) (Potatoes) 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 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 J.R. Simplot Company. This information concerns potato events GEN2-W8, GEN2-X17 and GEN2-Y9, with late blight resistance, lower free asparagine content, lower reducing sugar content, and lower expression of polyphenol oxidase. The CFIA has determined that potato events GEN2-W8, GEN2-X17 and GEN2-Y9 do not present altered environmental risk nor, as a novel feed, do they present livestock feed safety or nutrition concerns when compared to potato varieties currently grown and permitted to be used as livestock feed in Canada.

Taking into account these evaluations, the unconfined release into the environment and use as livestock feed of potato events GEN2-W8, GEN2-X17 and GEN2-Y9 are therefore authorized by the Plant Biosafety Office of the Plant Health and Biosecurity Directorate and by the Animal Feed Division of the Animal Health Directorate, respectively, as of July 31, 2017. Any potato lines derived from potato events GEN2-W8, GEN2-X17 and GEN2-Y9 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 potato 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 gene is expressed at a level similar to that of the authorized lines

Additionally, with respect to unconfined release into the environment, the cultivation of potato events GEN2-W8, GEN2-X17 and GEN2-Y9 is subject to disease resistance management requirements.

Potato events GEN2-W8, GEN2-X17 and GEN2-Y9 are subject to the same phytosanitary import requirements as unmodified potato varieties. Potato events GEN2-W8, GEN2-X17 and GEN2-Y9 are required to meet the requirements of other jurisdictions, including but not limited to, the Food and Drugs Act and the Pest Control Products Act.

Please note that the livestock feed and environmental assessments of novel feeds and plant with novel trait (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 31, 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.

On this page

  1. 1. Brief identification of the modified plant
  2. 2. Background information
  3. 3. Description of the novel traits
    1. 3.1 Development method
    2. 3.2 Reduced levels of free asparagine
    3. 3.3 Reduced levels of reducing sugars glucose and fructose
    4. 3.4 Reduced levels of polyphenol oxidase
    5. 3.5 Late blight disease resistance
    6. 3.6 Stable integration into the plant genome
      1. 3.6.1 Potato event GEN2-W8
      2. 3.6.2 Potato event GEN2-X17
      3. 3.6.3 Potato event GEN2-Y9
  4. 4. Criteria for the environmental assessment
    1. 4.1 Potential for potato events GEN2-W8, GEN2-X17 and GEN2-Y9 to become weeds of agriculture or be invasive of natural habitats
    2. 4.2 Potential for gene flow from potato events GEN2-W8, GEN2-X17 and GEN2-Y9 to sexually compatible plants whose hybrid offspring may become more weedy or more invasive
    3. 4.3 Potential for potato events GEN2-W8, GEN2-X17 and GEN2-Y9 to become plant pests
    4. 4.4 Potential impact of potato events GEN2-W8, GEN2-X17 and GEN2-Y9 or their gene products on non-target organisms, including humans
    5. 4.5 Potential impact of potato events GEN2-W8, GEN2-X17 and GEN2-Y9 on biodiversity
    6. 4.6 Potential for development of disease resistance to potato events GEN2-W8, GEN2-X17 and GEN2-Y9
  5. 5. Criteria for the livestock feed assessment
    1. 5.1 Potential impact of potato events GEN2-W8, GEN2-X17 and GEN2-Y9 on livestock nutrition
    2. 5.2 Potential impact of potato events GEN2-W8, GEN2-X17 and GEN2-Y9 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. 6. New information requirements
  7. 7. Regulatory decision

1. Brief identification of the modified plant

Designation of the modified plant:
Potato events GEN2-W8 (OECD Unique Identifier SPS-ØØØ-W8-4), GEN2-X17 (OECD Unique Identifier SPS-ØØ-X17-5 and GEN2-Y9 (OECD Unique Identifier SPS-ØØØ-Y9-7).
Applicant:
J.R. Simplot Company
Plant species:
Potato (Solanum tuberosum (L.))
Novel traits:
Late blight resistance, lower free asparagine content, lower reducing sugar content, and lower expression of polyphenol oxidase.
Trait introduction method:
Agrobacterium-mediated transformation
Intended use of the modified plant:
Potato events GEN2-W8, GEN2-X17 and GEN2-Y9 are intended to be grown for traditional human food and livestock feed uses. Potato events GEN2-W8, GEN2-X17 and GEN2-Y9 are not intended to be grown outside the normal production area for potatoes in Canada.

2. Background information

J.R. Simplot Company has developed 3 potato events, GEN2-W8, GEN2-X17 and GEN2-Y9, that have:

  • late blight resistance
  • lower free asparagine content, which decreases the potential for acrylamide formation during frying and baking
  • lower levels of the reducing sugars glucose and fructose, which improves the quality of tubers for processing and contributes to the decreased potential for acrylamide formation
  • lower expression of polyphenol oxidase, which decreases the potential for black spot bruising.

Potato event GEN2-W8 was developed by J.R. Simplot Company using recombinant deoxyribonucleic acid (DNA) technology, resulting in the introduction of 5 ribonucleic acid interference (RNAi) constructs (asparagine synthetase 1 (Asn1), water dikinase (R1), phosphorylase-L (PhL), polyphenol oxidase 5 (Ppo5) and endogenous potato vacuolar invertase (VInv) gene fragments), and 1 gene expression construct (Rpi-vnt1), into the Russet Burbank variety.

Potato events GEN2-X17 and GEN2-Y9 were developed using recombinant DNA technology, resulting in the introduction of 1 RNAi construct (VInv), and 1 gene expression construct (Rpi-vnt1) into 2 previously authorized potato events – Ranger Russet F10 and Atlantic J3, respectively (DD2016-114). The previously authorized Ranger Russet F10 and Atlantic J3 events already contain 4 RNAi constructs (Asn1, R1, PhL and Ppo5 gene fragments).

The Asn1, R1, PhL and VInv gene fragments were all derived from S. tuberosum var. Ranger Russet; the Ppo5gene fragment was derived from Solanum verrucosum, a wild relative of cultivated potatoes. The expression of Asn1, R1, PhL, Ppo5 and VInv gene fragments results in suppression of the RNA transcribed by the endogenous Asn1, R1, PhL, Ppo5 and VInv potato genes, conferring the lower acrylamide formation potential, reduced black spot bruising, and lower levels of reducing sugars traits.

The Rpi-vnt1 gene is derived from Solanum venturii, a wild relative of cultivated potatoes. Rpi-vnt1 encodes a resistance protein which recognizes a protein present in Phytophthora infestans, the pathogen that causes late blight disease. This protein recognition confers late blight resistance in potato plants expressing Rpi-vnt1.

J.R. Simplot Company has provided information on the identity of potato events GEN2-W8, GEN2-X17 and GEN2-Y9; a detailed description of the transformation method, and information on the inserted DNA, the levels of protein expression in the plant and the role of the inserted sequences. Information was provided for the evaluation of the potential toxicity of the novel proteins to livestock and non-target organisms and potential allergenicity of the novel proteins to humans and to livestock.

Potato events GEN2-W8, GEN2-X17 and GEN2-Y9 were field tested in the United States (US). Potato event GEN2-W8 was field tested at 3 locations in 2012 and 8 locations in 2013. Potato event GEN2-X17 was field tested at 6 locations in 2013 and 4 locations in 2014. Potato event GEN2-Y9 was field tested at 7 locations in 2014. The locations of these trials share similar environmental and agronomic conditions to potato production areas in Canada and were considered representative of major Canadian potato growing regions. Appropriate unmodified control potato varieties (that is, Russet Burbank, Ranger Russet or Atlantic), which share the same genetic background as potato event GEN2-W8, GEN2-X17 and GEN2-Y9 respectively, were included in the trials as comparators. Several reference potato varieties were also included in the field trials to establish ranges of comparative values that are typical of potato varieties currently grown in Canada.

Agronomic characteristics of potato events GEN2-W8, GEN2-X17 and GEN2-Y9, such as early emergence, final emergence, stems per plant, plant vigor, plant height, vine senescence, disease incidence, insect damage, and tuber yield, were compared to those of the unmodified control potato varieties and to the range established from the reference potato varieties.

Nutritional components of potato events GEN2-W8, GEN2-X17 and GEN2-Y9, such as protein, fat, moisture, ash, crude fibre, carbohydrates, total amino acids, free amino acids, vitamins, minerals and anti-nutrients were compared to those of the unmodified control potato varieties and to the range established by the reference potato varieties.

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

  • the potential for potato events GEN2-W8, GEN2-X17 and GEN2-Y9 to become weeds of agriculture or invasive of natural habitats
  • the potential for gene flow from potato events GEN2-W8, GEN2-X17 and GEN2-Y9 to sexually compatible plants whose hybrid offspring may become more weedy or more invasive
  • the potential for potato events GEN2-W8, GEN2-X17 and GEN2-Y9 to become plant pests
  • the potential impact of potato events GEN2-W8, GEN2-X17 and GEN2-Y9 and their gene products on non-target organisms, including humans
  • the potential impact of potato events GEN2-W8, GEN2-X17 and GEN2-Y9 on biodiversity

The Animal Feed Division (AFD) of the CFIA has also reviewed the above information with respect to the assessment criteria for determining the safety and nutrition of livestock feed, as described in section 2.6 – Guidelines for the Assessment of Novel Feeds: Plant Sources, of Chapter 2 of the RG-1 Regulatory Guidance: Feed Registration Procedures and Labelling Standards.

The AFD has considered both intended and unintended effects and similarities and differences between potato events GEN2-W8, GEN2-X17 and GEN2-Y9 and unmodified potato varieties relative to the safety and nutrition of feed ingredients derived from potato events GEN2-W8, GEN2-X17 and GEN2-Y9 for their intended purpose, including:

  • the potential impact of potato events GEN2-W8, GEN2-X17 and GEN2-Y9 on livestock nutrition
  • the potential impact of potato events GEN2-W8, GEN2-X17 and GEN2-Y9 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 potato events GEN2-W8, GEN2-X17 and GEN2-Y9 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

Potato events GEN2-W8, GEN2-X17 and GEN2-Y9 were developed through Agrobacterium-mediated transformation of potato cells and contain 5 RNAi constructs (Asn1, R1, PhL, Ppo5, VInv), and 1 gene expression construct (Rpi-vnt1), as well as their associated regulatory elements. Transformed plantlets were selected on the basis of detecting RNAi and Rpi-vnt1 constructs through the use of molecular diagnostic tools. Transformed plantlets were then grown to maturity, and successful transformants were chosen for further development based on molecular and agronomic evaluations.

Transcription of RNAi suppression cassettes does not result in the production of novel proteins; therefore, as it relates to RNAi-mediated traits, there is no risk of new protein toxins or allergens being introduced into potato events GEN2-W8, GEN2-X17, and GEN2-Y9. Small noncoding RNAs are present in all plants and animals where they play central roles in endogenous gene regulation and response to exogenous DNA, therefore, there is a history of consumption of small noncoding RNAs similar to those produced in potato events GEN2-W8, GEN2-X17 and GEN2-Y9. Finally, the systemic absorption of exogenous small noncoding RNAs present in crops by livestock and human bystanders is considered to be unlikely based on the multiple, existing biological barriers.

3.2 Reduced levels of free asparagine

Potato events GEN2-W8, GEN2-X17 and GEN2-Y9 were developed to have reduced levels of free asparagine through the down-regulation of the endogenous potato Asn1 gene. When potato tubers are fried or baked, the golden brown colour that forms is the result of the Maillard reaction, which occurs between free amino acids and reducing sugars. In some cases, and particularly with asparagine, acrylamide can form as a by-product of this reaction. In potato events GEN2-W8, GEN2-X17 and GEN2-Y9, transcription of the Asn1 gene suppression cassette results in reduced levels of endogenous Asn1 messenger RNA through the RNAi process, resulting in reduced ASN1 enzyme levels. Lower ASN1 enzyme levels results in reduced levels of free asparagine, which limits the potential for acrylamide formation during frying and baking.

The suppression cassettes in potato events GEN2-W8, GEN2-X17 and GEN2-Y9 contain promoters that are predominantly active in tubers. Northern blot analyses were used to compare the RNA levels of the endogenous Asn1 gene in tubers, leaves, stems, roots and flowers of potato events GEN2-W8, GEN2-X17 and GEN2-Y9 and their respective unmodified control potato varieties. The northern blot data demonstrated a reduction in the level of Asn1 RNA in tubers and flowers for all 3 events, when compared to the unmodified control potato variety. Additionally, Asn1 RNA was significantly reduced in leaves for events GEN2-X17 and GEN2-Y9 when compared to the unmodified controls.

For a more detailed discussion of the safety of small noncoding RNAs produced by the suppression cassette containing the sequence from the Asn1 gene from potato, see section 5.2: Potential Impact of Potato Events GEN2-W8, GEN2-X17 and GEN2-Y9 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 Reduced levels of reducing sugars glucose and fructose

Potato events GEN2-W8, GEN2-X17 and GEN2-Y9 were developed to have lower levels of reducing sugars through the down-regulation of the endogenous potato vacuolar invertase (VInv), phosphorylase-L (PhL) and water dikinase (R1) genes. High levels of reducing sugars in potato tubers can lead to excessive browning from the Maillard reaction during frying or baking. In potato events GEN2-W8, GEN2-X17 and GEN2-Y9, transcription of the suppression cassettes that include sequences from the VInv, PhL and R1 genes from potato are expected to result in lower levels of endogenous VInv, PhL and R1 messenger RNAs respectively, through the RNAi process, resulting in reduced VInv, PhL and R1 enzyme levels. Reduced levels of these enzymes limits the conversion of starch to reducing sugars, which in turn improves the quality of potato tubers with respect to frying and baking, and further limits the potential for acrylamide formation.

The suppression cassettes in potato events GEN2-W8, GEN2-X17 and GEN2-Y9 contain promoters that are predominantly active in tubers. Northern blot analyses were used to compare the RNA levels of the endogenous VInv, PhL and R1 genes in tubers, leaves, stems, roots and flowers of potato events GEN2-W8, GEN2-X17 and GEN2-Y9 and their respective unmodified control potato varieties. The northern blot data demonstrated a reduction in the level of VInv RNA in tubers of all 3 events, and of PhL RNA in tubers in GEN2-W8 and GEN2-Y9 events, when compared to the unmodified control potato tissues. The northern blots did not reveal any reduction of R1 RNA for any potato event when compared to the unmodified control potato varieties.

For a more detailed discussion of the safety of small noncoding RNAs produced by the suppression cassettes containing the sequences from the VInv, PhL and R1 genes from potato, see section 5.2: Potential Impact of Potato Events GEN2-W8, GEN2-X17 and GEN2-Y9 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 Reduced levels of polyphenol oxidase

Potato events GEN2-W8, GEN2-X17 and GEN2-Y9 were developed to have reduced levels of polyphenol oxidase 5 (PPO5) enzyme through the down-regulation of the endogenous potato Ppo5 gene. PPOs are a diverse group of enzymes that are responsible for browning of tissues following damage to plant cells, as occurs during cutting or bruising. In potato events GEN2-W8, GEN2-X17 and GEN2-Y9, the transcription of the Ppo5 gene suppression cassette results in reduced levels of endogenous Ppo5 messenger RNA through the RNAi process, resulting in reduced PPO5 enzyme levels. When tubers from potato events GEN2-W8, GEN2-X17 and GEN2-Y9 are subjected to mechanical damage, the tubers are less likely to develop a black spot bruise.

The suppression cassettes in potato events GEN2-W8, GEN2-X17 and GEN2-Y9 contain promoters that are predominantly active in tubers. Northern blot analyses were used to compare the RNA levels of the endogenous Ppo5 gene in tubers, leaves, stems, roots and flowers of potato events GEN2-W8, GEN2-X17 and GEN2-Y9 and their respective unmodified control potato varieties. The northern blot data demonstrated a reduction in the level of Ppo5 RNA in tubers in all 3 events in comparison to the respective unmodified control potato varieties.

For a more detailed discussion of the safety of small noncoding RNAs produced by the suppression cassette containing the sequence from the Ppo5 gene from potato, see section 5.2: Potential Impact of Potato Events GEN2-W8, GEN2-X17 and GEN2-Y9 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 Late blight disease resistance

Potato events GEN2-W8, GEN2-X17 and GEN2-Y9 were developed to have resistance to late blight disease caused by the pathogen P. infestans. This disease resistance trait was achieved through the introduction of the Rpi-vnt1 gene from the wild potato S. venturii. The Rpi-vnt1 gene encodes the VNT1 resistance protein. Expression of the VNT1 protein enables the potato plant to detect a protein produced by P. infestans, which triggers defense mechanisms in the potato plant that confer resistance to late blight.

The VNT1 protein produced in potato events GEN2-W8, GEN2-X17 and GEN2-Y9 is the same as the VNT1 protein produced in the wild potato S. venturii.

VNT1 protein expression in potato events GEN2-W8, GEN2-X17 and GEN2-Y9 is driven by the promoter of the Rpi-vnt1 gene from S. venturii. Attempts to measure VNT1 accumulation in GEN2-W8, GEN2-X17 and GEN2-Y9 events using polyclonal antibodies and western blots were unsuccessful, as VNT1 levels were lower than the limit of detection, which was empirically determined to be 9 picograms. Because the VNT1 protein accumulates at such low levels, reverse-transcription quantitative polymerase chain reaction (RT-qPCR) was used to verify the expression of Rpi-vnt1 RNA in leaf and tuber tissues of potato events GEN2-W8, GEN2-X17 and GEN2-Y9.

The potential allergenicity and toxicity of the VNT1 protein to livestock and non-target organisms was evaluated. The weight of evidence indicates that the VNT1 protein is unlikely to be allergenic, because the source of the Rpi-vnt1 gene, S. venturii, is not commonly associated with allergenicity. Furthermore, the amino acid sequence of the VNT1 protein lacks relevant similarities to known allergens. It was also concluded that the VNT1 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 because the amino acid sequence of the VNT1 protein lacks relevant similarities to known toxins. For a more detailed discussion of the potential allergenicity and toxicity of the VNT1 protein, see section 5.2: Potential Impact of Potato Events W18, GEN2-X17 and GEN2-Y9 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.

3.6 Stable integration into the plant genome

3.6.1 Potato event GEN2-W8

Southern blot analysis, whole genome sequencing, and traditional Sanger sequencing were used to characterize the inserted DNA in potato event GEN2-W8.

Potato event GEN2-W8 contains 1 intact copy of the RNAi expression cassette that contains the Asn1, Ppo5, PhL and R1 gene fragments, inserted at a single locus in the potato genome. Additional sequences representing insert fragment duplications at both sides of the insert were detected.

The VInv RNAi and Rpi-vnt1 gene expression cassettes were inserted at a single locus in the potato genome. A small deletion in the Rpi-vnt1 gene promoter was observed, but this did not affect the gene's ability to confer late blight resistance.

No backbone sequences from the plasmid vector, linked or unlinked to the inserts, were detected in potato event GEN2-W8.

The stability of the inserts within potato event GEN2-W8 was verified by Southern blot analysis over 3 generations of vegetative propagation.

3.6.2 Potato event GEN2-X17

Southern blot analysis, whole genome sequencing, and traditional Sanger sequencing were used to characterize the inserted DNA in potato event GEN2-X17.

Potato event GEN2-X17 contains RNAi expression cassettes comprising Asn1, Ppo5, PhL and R1 gene fragments, and their associated regulatory elements, inherited from the potato event F10, which was previously authorized by CFIA (DD2016-114) and Health Canada. A molecular characterization by Southern blot analysis, whole genome sequencing and Sanger sequencing confirmed that potato event GEN2-X17 contains the insert inherited from potato event F10.

Potato event GEN2-X17 also contains 1 intact copy of the VInv RNAi and Rpi-vnt1 gene expression cassettes, along with associated regulatory elements, inserted at a single locus in the potato genome. No additional elements, including intact or partial DNA fragments of the gene cassettes or backbone sequences from the plasmid vector, linked or unlinked to the intact insert, were detected in potato event GEN2-X17.

The stability of the inserts within potato event GEN2-X17 was verified by Southern blot analysis over 3 generations of vegetative propagation.

3.6.3 Potato event GEN2-Y9

Southern blot analysis, whole genome sequencing, and Sanger sequencing were used to characterize the inserted DNA in potato event GEN2-Y9.

Potato event GEN2-Y9 contains RNAi expression cassettes comprising Asn1, Ppo5, PhL and R1 gene fragments, as well as their regulatory elements, inherited from the potato event J3, which was previously authorized by CFIA (DD2016-114) and Health Canada. Molecular characterization by Southern blot analysis, whole genome sequencing, and Sanger sequencing confirmed that potato event GEN2-Y9 contains the insert inherited from potato event J3.

Potato event GEN2-Y9 also contains 1 intact copy of the VInv RNAi and Rpi-vnt1 gene expression cassettes, along with associated regulatory elements, inserted at a single locus in the potato genome. Aside from a short sequence representing a partial VInv RNAi cassette duplication at 1 end of the insert, no additional elements, including intact or partial DNA fragments of the expression cassettes or backbone sequences from the plasmid vector, linked or unlinked to the intact insert, were detected in potato event GEN2-Y9.

The stability of the inserts within potato event GEN2-Y9 was verified by Southern blot analysis over 3 generations of vegetative propagation.

4. Criteria for the environmental assessment

4.1 Potential of potato events GEN2-W8, GEN2-X17, and GEN2-Y9 to become weeds of agriculture or be invasive of natural habitats

The biology of potato, described in the CFIA biology document The Biology of Solanum tuberosum (L.) (Potatoes), is such that unmodified plants of this species are not invasive of unmanaged habitats in Canada. Although limited distribution is possible through dispersal of tubers, volunteers will not persist in cultivated habitats under normal agronomic practices, nor will they compete in uncultivated habitats. According to the information provided by J.R. Simplot Company, potato events GEN2-W8, GEN2-X17, and GEN2-Y9 were determined not to be significantly different from unmodified control potato varieties in this respect.

The CFIA evaluated data submitted by J.R. Simplot Company on the reproductive biology and life history traits of potato events GEN2-W8, GEN2-X17 and GEN2-Y9. As previously mentioned, potato event GEN2-W8 was tested in the US at 3 locations in 2012 and 8 locations in 2013. Potato event GEN2-X17 was tested in the US at 6 locations in 2013 and 4 locations in 2014. Potato event GEN2-Y9 was tested in the US at 7 locations in 2014. These locations share similar environmental and agronomic conditions to potato production areas in Canada, and were considered to be representative of major Canadian potato growing regions. During the field trials, potato events GEN2-W8, GEN2-X17 and GEN2-Y9 were compared to the unmodified control potato varieties (Russet Burbank, Ranger Russet and Atlantic, respectively). Reference potato varieties were also included in these trials to establish ranges of comparative values that are representative of potato varieties currently grown in Canada.

Phenotypic and agronomic traits were evaluated, covering a broad range of characteristics that encompass the entire life cycle of the potato plant. The traits included early emergence, final emergence, stems per plant, plant vigor, plant height, and vine senescence. Although instances of statistically significant differences were observed between potato events GEN2-W8, GEN2-X17 and GEN2-Y9 and their respective unmodified control potato varieties for some agronomic traits, the values for potato events GEN2-W8, GEN2-X17 and GEN2-Y9 were within the reference range established from the reference potato varieties included in the same field trials. Potato event GEN2-W8 showed increased plant vigor compared to its respective unmodified control potato variety, however the mean values for potato event GEN2-W8 were within the reference range established for the reference potato varieties included in the same field trials. Altered growth characteristics such as accelerated tuber sprouting, increased tuber set, delayed senescence, or key agronomic characteristics associated with weediness or survival outside of cultivation were not observed in potato events GEN2-W8, GEN2-X17 and GEN2-Y9. Agronomic and phenotypic assessments confirmed that potato events GEN2-W8, GEN2-X17 and GEN2-Y9 were similar in agronomic properties compared to their respective unmodified control potato varieties. Therefore, the instances of statistically significant differences for some agronomic traits are not considered biologically meaningful and the data support a conclusion of phenotypic and agronomic equivalence to currently grown potato varieties.

In addition, tuber yield and grading characteristics were also evaluated in the field at the same locations as the agronomic characteristic studies. Some of these locations produced smaller tubers and a few other locations produced larger tubers. However, these observations, if they persist in commercial production, would not contribute to weediness or invasiveness potential in Canada compared to currently grown potato varieties.

Potato events GEN2-W8, GEN2-X17, and GEN2-Y9 were exposed to frost, hail, heat, drought, and wind in the field during the agronomic characteristic studies. No trend in increased or decreased susceptibility to these abiotic stressors was observed in potato events GEN2-W8, GEN2-X17 and GEN2-Y9 in comparison to their respective unmodified control potato varieties.

The susceptibility of potato events GEN2-W8, GEN2-X17 and GEN2-Y9 to various potato pests and pathogens was evaluated in the field at the same locations as the agronomic characteristic studies (further detail provided below in section 3: Potential for Potato Events GEN2-W8, GEN2-X17, and GEN2-Y9 to Become a Plant Pest). No trend in increased or decreased susceptibility to pests or pathogens was observed in potato events GEN2-W8, GEN2-X17 and GEN2-Y9 when compared to their respective unmodified control potato varieties, except for the intended late blight resistance trait.

The volunteer potential of potato events GEN2-W8, GEN2-X17 and GEN2-Y9 was assessed at 3 sites in the US. Potato events GEN2-W8, GEN2-X17 and GEN2-Y9 were seeded in fall of 2013. A small number of volunteer plants were detected at 2 sites in the following spring; however there was no statistically significant difference between potato events GEN2-W8 and GEN2-Y9 and their respective unmodified control potato varieties. Potato event GEN2-X17 showed fewer volunteers than its unmodified control potato variety; and the values were within the range established by the reference potato varieties included in the same field trials.

No competitive advantage was conferred to potato events GEN2-W8, GEN2-X17 and GEN2-Y9, other than increased resistance to P. infestans, as the reproductive characteristics, growth characteristics and resistance to biotic and abiotic stressors of potato events GEN2-W8, GEN2-X17 and GEN2-Y9 were comparable to those of their respective unmodified control potato varieties. As late blight damage by P. infestans is not known to be a major factor restricting the establishment or distribution of potato in Canada, the introduction of late blight resistance is unlikely to make potato events GEN2-W8, GEN2-X17 or GEN2-Y9 weedy or invasive of natural habitats.

The novel traits have no intended or observed effects on weediness or invasiveness. The CFIA has therefore concluded that potato events GEN2-W8, GEN2-X17 and GEN2-Y9 have no altered weediness or invasiveness potential in Canada compared to currently grown potato varieties.

4.2 Potential for gene flow from potato events GEN2-W8, GEN2-X17, and GEN2-Y9 to sexually compatible plants whose hybrid offspring may become more weedy or more invasive

The biology of potato, as described in the CFIA biology document The Biology of Solanum tuberosum (L.) (Potatoes), indicates that there are no sexually compatible plants in Canada that can hybridize with potato.

The novel traits introduced into potato events GEN2-W8, GEN2-X17, and GEN2-Y9 (lowers levels of asparagine; lower levels of glucose and fructose; lower levels of polyphenol oxidase; and resistance to the P. infestans pathogen) are unrelated to conferring sexual compatibility with other species.

The CFIA has therefore concluded that gene flow from potato events GEN2-W8, GEN2-X17 and GEN2-Y9 to sexually compatible plants is not possible in Canada.

4.3 Potential for potato events GEN2-W8, GEN2-X17 and GEN2-Y9 to become a plant pest

Potato is not considered to be a plant pest in Canada. 2 of the traits introduced in potato events GEN2-W8, GEN2-X17 and GEN2-Y9 (lower levels of asparagine and lower levels of glucose and fructose) are unrelated to plant pest potential (for example the potential for the plant to harbor new or increased populations of pathogens or pests). Reduced levels of polyphenol oxidase and resistance to the P. infestans pathogen, however, may be related to plant pest potential. There is evidence that some PPO enzymes play a role in plant defense against pests and pathogens. As such, the susceptibility of potato events GEN2-W8, GEN2-X17 and GEN2-Y9 to various potato pests and pathogens was evaluated in the field at the same locations as the agronomic characteristic studies in 2012 to 2014. The stressors observed included aphids, Colorado potato beetle, flea beetles, loopers, potato leafhopper, grasshoppers, psyllids, black leg, black dot, early blight, late blight, brown leaf spot, Rizoctonia sp., Verticillium sp., leaf roll virus and white mold. Differences for the insect stressors Colorado potato beetle and stink bugs, and the disease stressors early blight, late blight and verticillium, were observed between potato event GEN2-W8 and its unmodified control potato variety, however all values for potato event GEN2-W8 were within the range for reference potato varieties, and no trends across sites were observed. Therefore, potato events GEN2-W8, GEN2-X17 and GEN2-Y9 did not show any increased or decreased susceptibility to these potato pests or pathogens compared to the unmodified control potato varieties.

The CFIA has therefore concluded that potato events GEN2-W8, GEN2-X17, and GEN2-Y9 do not display any altered plant pest potential compared to currently grown potato varieties.

4.4 Potential impact of potato events GEN2-W8, GEN2-X17 and GEN2-Y9 or their gene products on non-target organisms, including humans

3 of the 4 novel traits introduced into potato events GEN2-W8, GEN2-X17 and GEN2-Y9 (lower levels of asparagine; lower levels of glucose and fructose; lower levels of polyphenol oxidase) have been previously assessed by the CFIA (DD2016-114), and found to not have an impact on non-target organisms.

Potato events GEN2-W8, GEN2-X17 and GEN2-Y9 express the VNT1 protein that confers resistance to the late blight disease. Disease resistance proteins (R-proteins) such as VNT1 do not target the pathogen directly or act as toxins. The VNT1 protein recognizes a specific protein secreted by P. infestans. This recognition event triggers a response pathway already present in the plant cell, resulting in a hypersensitive response that destroys infected plant tissues through programmed cell death. The death of the host plant cells restricts the spread of the pathogen.

R-proteins like VNT1 are a highly conserved class of plant proteins, and non-target organisms have been frequently exposed to R-proteins with no evidence of detrimental effects. The introduced Rpi-vnt1 gene from Solanum venturii is identical to the Rpi-phu1 genefound in Solanum tuberosum (group Phureja), a cultivar group with a history of safe use and a source of genetic material in the improvement of potato varieties. Results of bioinformatic analyses demonstrate that the amino acid sequence of the VNT1 protein lacks homology to any known toxins or allergens. Furthermore, R-proteins are expressed at very low concentrations in plants, limiting exposure to non-target organisms, including humans.

Collectively, these information elements indicate that the expression of the VNT1 protein in potato events GEN2-W8, GEN2-X17 and GEN2-Y9 is very unlikely to pose a risk to non-target organisms, including humans.

The suppression cassettes introduced in potato events GEN2-W8, GEN2-X17 and GEN2-Y9 were designed to downregulate target genes through the mechanism of RNAi. Small non-coding RNA molecules are present in cells of all plants and animals, where they play central roles in endogenous gene regulation and response to exogenous DNA. Therefore, there is a history of consumption of small non-coding RNA molecules similar to those produced in potato events GEN2-W8, GEN2-X17 and GEN2-Y9. The suppression cassettes were not designed to mediate gene suppression in any organism except potato. Based on the limited degree of sequence conservation between the targeted genes and any DNA sequences outside of the plant kingdom, gene suppression is unlikely to occur unintentionally. Therefore, no negative impacts on non-target organisms resulting from exposure to small noncoding RNAs expressed from the suppression cassettes in potato events GEN2-W8, GEN2-X17, and GEN2-Y9 are expected.

Compositional analyses showed that there were some statistically significant differences in key nutrients between potato events GEN2-W8, GEN2-X17 and GEN2-Y9 and their respective unmodified control potato varieties, including levels of asparagine and the reducing sugars glucose and fructose. However, all values, including levels of asparagine, glucose and fructose, were within the range established by the reference potato varieties grown at the same time and/or values published in the literature. Therefore, differences between potato events GEN2-W8, GEN2-X17 and GEN2-Y9 and their respective unmodified control potato varieties are not expected to be biologically significant (see section V, part 1: Potential impact of potato events GEN2-W8, GEN2-X17 and GEN2-Y9 on livestock nutrition). In addition, the glycoalkaloid levels in potato events GEN2-W8, GEN2-X17 and GEN2-Y9 were found to be similar to those of their respective unmodified control potato varieties. Therefore, it is unlikely that the introduction of the novel traits may have caused unintended changes to the composition of potato events GEN2-W8, GEN2-X17 and GEN2-Y9 tissues that would negatively impact organisms interacting with potato events GEN2-W8, GEN2-X17 and GEN2-Y9.

With the exception of intended increased resistance to P. infestans, field evaluations of potato events GEN2-W8, GEN2-X17 and GEN2-Y9 did not show any increased resistance to potato pests or pathogens compared to their respective unmodified control potato varieties (see section IV, part 3: Potential for potato Events GEN2-W8, GEN2-X17 and GEN2-Y9 to become a plant pest).

Collectively, these information elements indicate that the interactions of potato events GEN2-W8, GEN2-X17 and GEN2-Y9 with the populations of animals and microorganisms (other than P. infestans) that interact with potato crops will be similar compared to currently grown potato varieties.

The CFIA has therefore determined that the unconfined environmental release of potato events GEN2-W8, GEN2-X17 and GEN2-Y9 in Canada will not result in altered impacts on non-target organisms, including humans, compared to currently grown potato varieties.

4.5 Potential impact of potato events GEN2-W8, GEN2-X17 and GEN2-Y9 on biodiversity

Potato events GEN2-W8, GEN2-X17 and GEN2-Y9 express no novel phenotypic characteristics that would extend their range beyond the current geographic range of potato production in Canada. Since potato has no wild relatives with which it can outcross in Canada, there will be no transfer of the novel traits to other species in unmanaged environments. Potato events GEN2-W8, GEN2-X17 and GEN2-Y9 are unlikely to cause adverse effects on non-target organisms and do not display increased weediness, invasiveness or plant pest potential. It is therefore unlikely that potato events GEN2-W8, GEN2-X17 and GEN2-Y9 will have any direct effects on biodiversity, in comparison to the effects that would be expected from the cultivation of potato varieties that are currently grown in Canada.

The CFIA has concluded that the introduced DNA sequences and their corresponding traits do not confer to potato events GEN2-W8, GEN2-X17 and GEN2-Y9 any characteristic that would result in unintended environmental effects following unconfined release. The CFIA has therefore concluded that the potential impact on biodiversity of potato events GEN2-W8, GEN2-X17 and GEN2-Y9 is unlikely to be different from that of the potato varieties that are currently grown in Canada.

4.6 Potential for development of disease resistance to potato events GEN2-W8, GEN2-X17 and GEN2-Y9

To minimize the likelihood of development of resistance in target pathogens, the CFIA requires that a disease resistance management (DRM) plan be implemented for PNTs expressing disease resistance traits. Many pathogens are able to overcome control measures. A DRM plan designed to reduce or delay the ability of P. infestans to circumvent the VNT1 R-protein must be implemented for the cultivation of potato events GEN2-W8, GEN2-X17 and GEN2-Y9 in Canada. The CFIA believes that sound management practices and integrated pest management strategies can reduce and delay the development of P. infestans populations resistant to the VNT1 R-protein.

The CFIA understands that J.R. Simplot Company has developed, and will implement, a DRM plan that includes the following key components:

  • education tools will be developed and provided to all growers, district managers and field managers. These will include information on product performance, resistance management, integrated pest management, instructions to contact J.R. Simplot Company and strategies to be followed if unexpected levels of P. infestans damage occur
  • integrated pest management practices will be promoted, such as crop rotation, control of volunteers and use of disease forecasting tools

5. Criteria for the livestock feed assessment

The AFD considered nutrient and anti-nutrient profiles; the safety of feed ingredients derived from potato events GEN2-W8, GEN2-X17, and GEN2-Y9, 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 potato events GEN2-W8, GEN2-X17, and GEN2-Y9 meet the definitions and requirements of feeds as listed in Schedule IV of the Feeds Regulations.

5.1 Potential impact of potato events GEN2-W8, GEN2-X17 and GEN2-Y9 on livestock nutrition

Nutrient and anti-nutrient composition

The nutritional equivalence of potato events GEN2-W8, GEN2-X17, and GEN2-Y9 to their corresponding unmodified control varieties and 7 reference potato varieties was determined from multiple field trials conducted in US during potato growing seasons. During 2012 and 2013, potato event GEN2-W8 and the unmodified control variety, Russet Burbank, were grown at 11 locations. Potato event GEN2-X17 and the unmodified control variety, Ranger Russet, were grown at 8 locations during 2013 and 2014, while potato event GEN2-Y9 and the unmodified control variety, Atlantic, were grown at 7 locations in 2014. Potato tuber samples (with skin) from potato events GEN2-W8, GEN2-X17 and GEN2-Y9 and their unmodified control potato varieties were analyzed for moisture, ash, protein, fat, crude fibre, carbohydrates, calories, total amino acids, free amino acids, vitamins, minerals, and antinutrients (glycoalkaloids) as recommended by the Organisation for Economic Co-operation and Development (OECD) consensus document for new varieties of potatoes (OECD 2002). In addition, reducing sugars and decreased acrylamide traits in processed products from potato events GEN2-W8, GEN2-X17 and GEN2-Y9 were evaluated during storage. Samples of potato events GEN2-W8 and GEN2-X17 and their unmodified control potato varieties were processed into fries while potato event GEN2-Y9 and the unmodified control potato variety were processed into potato chips. Composition data was analysed statistically by combining data from multiple years and locations using a linear mixed model. Statistical differences among potato events GEN2-W8, GEN2-X17 and GEN2-Y9 and their unmodified control potato varieties were identified (P < 0.05). The biological relevance of any statistically significant differences between potato events GEN2-W8, GEN2-X17 and GEN2-Y9 and their respective unmodified control potato varieties were compared with the range of the values of the reference potato varieties grown in the trials and/or in the published scientific literature. These findings are detailed below.

No statistically significant differences were observed between tubers from potato event GEN2-W8 and the unmodified control potato variety for moisture, ash, protein, fat, crude fibre, carbohydrates and calories. Except for crude fibre, no statistically significant differences were observed between tubers from potato event GEN2-X17 and the unmodified control potato variety for moisture, protein, fat, ash, carbohydrates and calories. However, this difference was not biologically significant as the mean was within the range of the values observed in the reference potato varieties grown in the trials. No statistically significant differences were observed between tubers from potato event GEN2-Y9 and the unmodified control potato variety for fat and ash. Statistically significant effects were found between tubers from potato event GEN2-Y9 and the unmodified control potato variety for protein, fibre, carbohydrates, calories and moisture. However, these differences were not biologically significant, as all means were within the range of the values observed in the reference potato varieties grown in the trials. Levels of reducing sugars (fructose and glucose) observed at the time of harvest and at up to 9 months of storage were significantly lower for potato events GEN2-W8, GEN2-X17 and GEN2-Y9 when compared to their respective unmodified control potato varieties. All means were within the ranges of values of the reference potato varieties grown in the trials.

Free asparagine levels were statistically significantly lower in potato events GEN2-W8 and GEN2-Y9 compared to their respective unmodified control potato varieties, but the means were within the range of the values of the reference potato varieties grown in the trials. Conversely, statistically significantly higher free glutamine was observed in potato events GEN2-W8, GEN2-X17 and GEN2-Y9 compared to their respective unmodified control potato varieties; however the means were within the range of the values of the reference control potato varieties grown in the trials. Free glutamic acid was significantly higher in potato events GEN2-W8, GEN2-X17 and GEN2-Y9 compared to their unmodified control potato varieties, but the means were within the range of the values of the reference potato varieties grown in the trials. Free aspartic acid was significantly higher in potato event GEN2-W8 compared to its unmodified control potato variety, but the mean was within the range of the values of the reference potato varieties grown in the trials.

Statistically significant differences were found between tubers from potato event GEN2-W8 and the unmodified control potato variety for amino acids alanine, aspartic acid, asparagine, cystine, glutamic acid, glutamine, glycine, leucine, proline, serine, threonine and tyrosine. However, the means were within the ranges of the values observed in the reference potato varieties grown in the trials. Statistically significant differences were found between tubers from potato event GEN2-X17 and the unmodified control potato variety for all amino acids except for histidine and tryptophan. However, all means were within the ranges of the values observed in the reference potato varieties grown in the trials. Except for lysine and methionine, statistically significant differences were found between tubers from potato event GEN2-Y9 and the unmodified control potato variety for amino acids. However, all means were within the ranges of the values observed in the reference potato varieties grown in the trials.

Statistically significant differences were found between tubers from potato event GEN2-W8 and the unmodified control potato variety for vitamins B6 and vitamin C. However, these differences were not biologically significant as the means were within the ranges of the values observed in the reference potato varieties grown in the trials. A statistically significant difference was found between tubers from potato event GEN2-X17 and the unmodified control potato variety for vitamin C. However, this difference was not biologically significant as the mean was within the range of the values observed in the reference potato varieties grown in the trials. No statistically significant differences were observed between tubers from potato event GEN2-Y9 and the unmodified control potato variety for vitamin C.

No statistically significant differences were observed between tubers from potato event GEN2-W8 and the unmodified control potato variety for minerals. Except for potassium, no statistically significant differences were observed between tubers from potato events GEN2-X17 and GEN2-Y9 and the unmodified control potato variety for minerals. However, the difference was not biologically significant as the mean was within the range of the values observed in the reference potato varieties grown in the trials.

No statistically significant differences were observed between tubers from potato events GEN2-W8, GEN2-X17 and GEN2-Y9 and the unmodified control potato for glycoalkaloids.

The levels of acrylamide were statistically significantly lower in all 3 processed potato events when compared to their respective unmodified control potato varieties during storage. On average, the acrylamide levels in fries made from potato events GEN2-W8 and GEN2-X17 and in potato chips made from potato event GEN2-Y9 were statistically significantly lower (78.2 – 96.8%) than in the respective products made from unmodified control potato varieties during the storage period (3-9 months). However, the mean acrylamide levels in the 3 potato events were within the range of the values for the reference potato varieties.

Conclusions

It was concluded, based on the evidence provided by J.R. Simplot Company, that the nutritional composition of the potato events GEN2-W8, GEN2-X17 and GEN2-Y9 are similar to their respective unmodified potato varieties, except for decreased free asparagine, increased free glutamine and decreased reducing sugars, thereby reducing acrylamide formation, in stored and subsequently processed products. Feed ingredients derived from potato events GEN2-W8, GEN2-X17 and GEN2-Y9 are considered to meet present ingredient definitions for potatoes, since the levels of free asparagine, glutamine and acrylamide are within the range of the values established for the reference potato varieties.

5.2 Potential impact of potato events GEN2-W8, GEN2-X17 and GEN2-Y9 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

Potato events GEN2-W8, GEN2-X17 and GEN2-Y9 display reduction of acrylamide levels due to RNAi-mediated down-regulation of endogenous enzymes involved in the production of asparagine and reducing sugars, reduction of black spot due to RNAi-mediated down-regulation of endogenous enzyme PPO5, and tolerance to late blight due to production of the VNT1 protein. A weight-of-evidence approach was used to evaluate the risks associated with exposure to potato events GEN2-W8, GEN2-X17 and GEN2-Y9, whether by livestock consuming feed ingredients, from humans consuming foods of animal origin derived from those livestock, or by worker/bystander exposed to the feed ingredients. The following aspects of these events were evaluated:

  • the small interfering ribonucleic acid (siRNA) molecules derived from the insert segments of Asn1, R1, PhL, and Ppo5 genes
  • the siRNA molecules derived from the insert segment of VInv gene
  • the novel VNT1 protein

siRNA molecules derived from the insert segments of Asn1, R1, PhL, and Ppo5 genes

The potato events GEN2-W8, GEN2-X17 and GEN2-Y9 contain the same genetic inserts of Asn1, R1, PhL and Ppo5 as previously approved potato events GEN1-F10, GEN1-E12, GEN1-J3, and GEN1-J55, which were found to be as safe as conventional potato (DD2016-114). Safety data for the siRNA molecules derived from inserts of Asn1, R1, PhL and Ppo5 indicate that the inserted gene segments of Asn1, R1, PhL, and Ppo5 in potato events GEN2-W8, GEN2-X17 and GEN2-Y9 were not considered to present a risk to human or animal health or to the environment, as they are not associated with a toxic mode of action. There is no rationale linking reductions in ASN1, R1, PHL, and PPO5 enzyme levels to impacts on endogenous potato toxin or allergen levels.

siRNA molecules derived from the VInv gene suppression cassette

The transcription of VInv gene fragments results in the production of siRNA molecules, which triggers the RNAi-mediated down-regulation of the endogenous VInv potato gene, and the subsequent decrease in VInv protein expression. This does not result in the production of novel proteins. The livestock feed safety assessment of potato events GEN2-W8, GEN2-X17 and GEN2-Y9 thus focused on the safety of the siRNA molecules derived from the VInv gene suppression cassette and the resultant reduced abundance of VInv enzyme.

Reductions in VInv enzyme levels in potato events GEN2-W8, GEN2-X17 and GEN2-Y9 were not considered to present a risk to human or animal health or to the environment, as they are not associated with a toxic mode of action. There is no rationale linking reductions in VInv enzyme levels to impacts on endogenous potato toxin or allergen levels.

siRNA molecules in potato events GEN2-W8, GEN2-X17 and GEN2-Y9 were not considered to present a risk to human or animal health or to the environment, as bioinformatics analyses indicated that the VInv DNA sequence inserted into potato events GEN2-W8, GEN2-X17 and GEN2-Y9 and the potential siRNA sequences derived from the VInv inserts did not have significant sequence similarity to protein-coding genomic regions of livestock or humans, and thus were not expected to affect livestock or human protein expression. In addition, the systemic absorption of exogenous RNA molecules in crops by livestock is considered to be unlikely based on well-described biological barriers. Furthermore, a 90-day tolerance study demonstrated that no test-diet-related adverse effects were observed in rats consuming a diet containing GEN2-W8, GEN2-X17 or GEN2-Y9 potato powder up to a 20% inclusion level, when compared with rats consuming diets containing unmodified potato powder. This provides additional support for the safety of siRNA molecules derived from the insert fragments of VInv gene in potato events GEN2-W8, GEN2-X17 and GEN2-Y9.

The weight of evidence thus indicated that the inserted VInv gene fragments and resultant siRNA molecules in potato events GEN2-W8, GEN2-X17 and GEN2-Y9 are unlikely to pose a risk to livestock, humans consuming foods of animal origin derived from those livestock, and worker/bystander exposed to the feed.

VNT1 protein

The potential allergenicity and toxicity of the VNT1 protein encoded by the Rpi-vnt1 gene were evaluated.

In terms of the potential allergenicity, the source of the Rpi-vnt1 gene, Solanum venturii, is not expected to produce allergens, and a bioinformatics analysis of the VNT1 protein amino acid sequence demonstrated a lack of relevant similarities between this protein and known allergens. Additionally, there is a history of safe use of the host organism and a history of safe exposure to the VNT1 protein. As such, the weight of evidence indicates that the VNT1 protein is unlikely to raise a concern for allergenicity.

In terms of the potential toxicity, the VNT1 protein lacks a mode of action to suggest that it is intrinsically toxic to livestock, and a bioinformatics analysis of the amino acid sequence demonstrated a lack of relevant similarities between the VNT1 protein and known toxins. Livestock exposure to the VNT1 protein is expected to be extremely low, as this protein was undetectable in leaf and tuber tissues of potato events GEN2-W8, GEN2-X17 and GEN2-Y9, using liquid chromatography-mass spectrometry (LC-MS) with a limit of detection of 500 ppb, and western blots with a limit of detection 280 ppb. A 90-day tolerance study demonstrated that no test-diet-related adverse effects were observed in rats consuming a diet containing potato events GEN2-W8, GEN2-X17 or GEN2-Y9 powder up to 20% of the diet, compared with rats consuming diets containing unmodified potato powder. This provides additional support for the safety of the VNT1 protein in potato events GEN2-W8, GEN2-X17 and GEN2-Y9. The weight of evidence thus indicated that the VNT1 protein is unlikely to raise a concern for toxicity.

Therefore, the VNT1 protein in potato events GEN2-W8, GEN2-X17 and GEN2-Y9 is unlikely to pose a risk to livestock, humans consuming foods of animal origin derived from those livestock, and worker/bystander exposed to feed ingredients.

Conclusions

It was concluded, based on the evidence provided by J.R. Simplot Company, that the novel traits will not confer to potato events GEN2-W8, GEN2-X17 and GEN2-Y9 any characteristic that would raise concerns regarding the safety of potato events GEN2-W8, GEN2-X17 and GEN2-Y9. Feed ingredient(s) from potato events GEN2-W8, GEN2-X17 and GEN2-Y9 are considered to meet present ingredient definitions for potato in the Feeds Regulations and as such are approved for use as livestock feed in Canada.

6. New information requirements

If at any time, J.R. Simplot 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 potato events GEN2-W8, GEN2-X17 and GEN2-Y9 or lines derived therefrom, J.R. Simplot 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 potato events GEN2-W8, GEN2-X17 and GEN2-Y9 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 potato events GEN2-W8, GEN2-X17 and GEN2-Y9.

7. Regulatory decision

Based on the review of the data and information submitted by J.R. Simplot Company and input from other relevant scientific sources, the Plant Biotechnology Risk Assessment Unit of the Plant Health Science Directorate, CFIA, has concluded that the unconfined environmental release of potato events GEN2-W8, GEN2-X17 and GEN2-Y9 does not present altered environmental risk when compared to potato varieties that are currently grown in Canada.

Based on the review of the data and information submitted by J.R. Simplot Company and input from other relevant scientific sources, the Animal Feed Division of the Animal Health Directorate, CFIA, has concluded that the lower acrylamide potential, lower reducing sugars, reduced black spot, and improved late blight resistance traits will not confer to potato events GEN2-W8, GEN2-X17 and GEN2-Y9 any characteristic that would raise concerns regarding the safety or nutrition of potato events GEN2-W8, GEN2-X17 and GEN2-Y9. Livestock feeds derived from potato are currently listed in Schedule IV of the Feeds Regulations. Potato events GEN2-W8, GEN2-X17 and GEN2-Y9 have been found to be as safe as and as nutritious as currently and historically grown potato varieties. Potato events GEN2-W8, GEN2-X17 and GEN2-Y9 and their products are considered to meet present ingredient definitions.

Unconfined release into the environment and use as livestock feed of potato events GEN2-W8, GEN2-X17 and GEN2-Y9 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 July 31, 2017. Any potato lines derived from potato events GEN2-W8, GEN2-X17 and GEN2-Y9 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 potato 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 gene is expressed at a level similar to that in the authorized lines

Additionally, with respect to unconfined release into the environment, the cultivation of potato events GEN2-W8, GEN2-X17 and GEN2-Y9 is subject to disease resistance management requirements.

Potato events GEN2-W8, GEN2-X17 and GEN2-Y9 are subject to the same phytosanitary import requirements as unmodified potato varieties. Potato events GEN2-W8, GEN2-X17 and GEN2-Y9 are required to meet the requirements of other jurisdictions, including but not limited to, the Food and Drugs Act and the Pest Control Products Act.

Please refer to Health Canada's Decisions on Novel Foods for a description of the food safety assessment of potato events GEN2-W8, GEN2-X17 and GEN2-Y9. The food safety decisions are available on the Health Canada website.