Novel Food Information - Simplot Innate® Potato Events Gen2-W8, Gen2-X17, and Gen2-Y9

Health Canada has notified J.R. Simplot Company that it has no objection to the food use of Simplot Innate® potato events Gen2-W8, Gen2-X17, and Gen2-Y9. The Department conducted a comprehensive assessment of these potato events according to its Guidelines for the Safety Assessment of Novel Foods. These Guidelines are based upon internationally accepted principles for establishing the safety of foods with novel traits.

BACKGROUND:

The following provides a summary of the notification from J.R. Simplot Company and the evaluation by Heath Canada and contains no confidential business information.

1. Introduction

J.R. Simplot Company has developed three genetically modified potato events (i.e., 1 Russet Burbank variety, 1 Ranger Russet variety, and 1 Atlantic variety, respectively) using recombinant DNA techniques. These potato events exhibit reduced levels of free asparagine in tubers, as well as lower levels of reducing sugars (i.e., glucose and fructose) in tubers. The reduction in asparagine alone significantly decreases acrylamide formation in tubers when subjected to various forms of thermal processing (e.g., baking, frying, etc.) however lower levels of reducing sugars further decreases acrylamide formation and limit heat-induced browning. These potato events also exhibit reduced expression of polyphenol oxidase 5 enzyme (Ppo5), resulting in a decreased incidence of black spot bruising in tubers. Lastly, these potato events express a resistance protein (R-protein) found in wild Solanum species Solanum venturii and Solanum phureja (VNT1). The VNT1 protein enables the potato plant to detect an effector protein, Avr-Vnt1, which is produced by Phytopthora infestans; an oomycete that causes late blight in potatoes. Detection of the effector protein allows the potato plant to initiate its native immune response to resist infection by P. infestans.

With the exception of late blight resistance, the other novel traits (i.e. reduced asparagine levels, lower levels of reducing sugars, and reduced black spot bruising) are achieved through the transcription of inverted repeat sequences containing small fragments of DNA from five different endogenous genes (i.e., Asn1, Ppo5, PhL, R1, and VInv), which results in the reduced level of mRNA transcripts (and subsequently expressed proteins) for those same genes using the RNA interference (RNAi) pathway. As mentioned above, the late blight resistance trait is achieved through the expression of the VNT1 protein.

Simplot Innate® potato events Gen2-W8, Gen2-X17, and Gen2-Y9 are considered by their developer to be ‘Generation 2.0’ plants. The first generation of Simplot Innate® potato events (i.e., Gen1-E12, Gen1-F10, Gen1-J3, Gen1-J55, and Gen1-V11) exhibit lower levels of reducing sugars, have lower potential to form acrylamide during heat processing, and exhibit resistance to black spot bruising. The second generation of Simplot Innate® potato events possess all the same traits as their Generation 1.0 predecessors, while also exhibiting resistance to late blight disease.

The safety assessment performed by Food Directorate evaluators was conducted according to Health Canada’s Guidelines for the Safety Assessment of Novel Foods. These Guidelines are based on harmonization efforts with other regulatory authorities and reflect international guidance documents in this area (e.g., Codex Alimentarius).  The assessment considered: how these potato events were developed; how the composition and nutritional quality of these events compared to non-modified potato varieties; and the potential for these potato events to be toxic or cause allergic reactions. J.R. Simplot Company has provided data that demonstrate that Simplot Innate® potato events Gen2-W8, Gen2-X17, and Gen2-Y9 are as safe and of the same nutritional quality as traditional potato varieties used as food in Canada.

The Food Directorate has a legislated responsibility for pre-market assessment of novel foods and novel food ingredients as detailed in the Food and Drug Regulations (Division B.28). Simplot Innate® potato events Gen2-W8, Gen2-X17, and Gen2-Y9 are considered novel foods under the following part of the definition of novel foods: “c) a food that is derived from a plant, animal or microorganism that has been genetically modified such that

(i) the plant, animal or microorganism exhibits characteristics that were not previously observed in that plant, animal or microorganism.” 

2. Development of the Modified Plant

The petitioner has provided information describing the methods used to develop Simplot Innate® potato events Gen2-W8, Gen2-X17, and Gen2-Y9 and the molecular biology data that characterize the genetic change, which results in reduced levels of free asparagine in tubers, lower levels of reducing sugars (i.e., glucose and fructose) in tubers, reduced expression of polyphenol oxidase 5 enzyme (Ppo5), and expression of the VNT1 protein. This phenotype was achieved by transformation of the conventional potato varieties Russet Burbank, Ranger Russet, and Atlantic with two different T-DNA constructs containing inverted repeat sequences consisting of specific DNA fragments from five endogenous genes (i.e., Asn1, Ppo5, PhL, R1, and VInv) and the Rpi-vnt1 gene derived from S. venturii encoding the VNT1 protein. The five endogenous target genes were chosen based upon their biochemical roles in asparagine production, accumulation of reducing sugars, or black spot bruising. The T-DNA inserts in Simplot Innate® potato events Gen2-W8, Gen2-X17, and Gen2-Y9 contain two native promoters (i.e., pAgp and pGbss) that drive the transcription of three inverted repeat sequences, primarily in tuber tissue. Expression of these inverted repeat sequences results in the reduced level of mRNA (and subsequently expressed proteins) for those same genes using the RNA interference (RNAi) pathway.

The Asn1 gene encodes an asparagine synthetase 1 (Asn1) enzyme that catalyses the conversion of glutamine to asparagine by transferring the side-chain amine (NH2) from glutamine to aspartate to form asparagine. Asparagine is a substrate of the Maillard reaction which converts amino acids and reducing sugars to acrylamide during high-temperature processing. Reduction of Asn1 and asparagine levels in potato tubers results in a decreased potential for acrylamide formation in cooked potato food products.

The Ppo5 gene (as previously mentioned) encodes a polyphenol oxidase 5 (Ppo5) enzyme that catalyzes the conversion of o-diphenols to o-quinones. Reactive o-quinone molecules auto-polymerize to form melanins, which are responsible for the colouration of oxidized plant tissues. A loss of Ppo5 activity limits the colouration of oxidized tissues (thus reducing black spot bruising).

The PhL gene encodes an a-glucan phosphorylase, starch phosphorylase L (PhL) that degrades starch by phosphorolytic release of glucose-1-phosphate from glucan chains. A loss of PhL activity limits reducing sugar accumulation (further contributing to the lower potential for acrylamide formation).

The R1 gene encodes a starch-related R1 protein (a-glucan, water dikinase) that catalyzes the transfer of the g- and b-phosphates of ATP (through a phosphor-histidine intermediate) to α-glucan and water, resulting in phosphorylated starch. R1 is mainly responsible for phosphorylation at the C6 position. Phosphorylation affects the degree of crystalline packing within the starch granule and makes it more accessible to degradation. Thus, loss of R1 activity impairs starch degradation, which reduces accumulation of reducing sugars (further contributing to the lower acrylamide potential phenotype).

The VInv gene encodes a vacuolar invertase (VInv) that hydrolyses sucrose into the reducing sugars glucose and fructose. Thus, loss of VInv activity reduces accumulation of reducing sugars (further contributing to the lower acrylamide potential phenotype).

Due to the nature of the inverted repeat sequences, their transcripts form double-stranded RNA (dsRNA) molecules through complementary binding. The dsRNA molecules act as a precursor for the plant’s own RNAi post-transcriptional regulatory pathway. A cellular RNase III enzyme (i.e. Dicer) recognizes and processes these precursor dsRNA molecules into small, 21-bp duplexes consisting of two individual strands (denoted as ‘guide’ and ‘passenger’, respectively) termed small interfering RNA (siRNA). The siRNA duplexes are subsequently bound by the RNA Induced Silencing Complex (RISC), which selectively degrades the ‘passenger’ strand of each duplex. The ‘guide’ strand (still bound to the Complex) serves to activate RISC and turn it into a silencing complex. In plants, the activated RISC binds to any messenger RNA (mRNA) that has complete complementary sequence to the bound ‘guide’ strand, and destroys the bound mRNA by enzymatic cleavage. The cleavage of the target mRNA can result in reduced expression of the associated protein (although this reduction in expression can vary for individual siRNA).

The first T-DNA construct (henceforth referred to as the pSIM1278 T-DNA) contains the following genetic elements: the promoter for an ADP glucose pyrophosphorylase gene (pAgp) (1st copy), one of two convergent promoters that drive the expression of an inverted repeat sequence containing fragments of the Asn1 and Ppo5 genes, derived from Solanum tuberosum (potato) var. Ranger Russet; the inverted repeat sequence containing fragments of the Asn1 and Ppo5 genes, the promoter for the granule-bound starch synthase (pGbss) gene (in the reverse orientation) (1st copy), the second of two convergent promoters that drive the expression of the inverted repeat sequence containing fragments of the Asn1 and Ppo5 genes, derived from S. tuberosum var. Ranger Russet; the promoter for an ADP glucose pyrophosphorylase gene (pAgp) (2nd copy), one of two convergent promoters that drive the expression of an inverted repeat sequence containing fragments of the PhL and R1 genes, derived from S. tuberosum var. Ranger Russet; the inverted repeat sequence containing fragments of the PhL and R1 genes, and the promoter for the granule-bound starch synthase (pGbss) gene (in the reverse orientation) (2nd copy), the second of two convergent promoters that drive the expression of the inverted repeat sequence containing fragments of the PhL and R1 genes, derived from S. tuberosum var. Ranger Russet. The pSIM1278 T-DNA construct was used in the development of Simplot Innate® potato events Gen1-E12, Gen1-F10, Gen1-J3, Gen1-J55, and Gen1-V11 and has been previously assessed by Health Canada (2016).

The second T-DNA construct (henceforth referred to as the pSIM1678 T-DNA) contains the following genetic elements: the native promoter for the R-protein, VNT1 (pRpi-vnt1) derived from S. venturii; the coding sequence of the Rpi-vnt1 gene (Rpi-vnt1) derived from S. venturii encoding the VNT1 protein; the native terminator for the R-protein, VNT1 (tRpi-vnt1) derived from S. venturii; the promoter for an ADP glucose pyrophosphorylase gene (pAgp) derived from S. tuberosum var. Ranger Russet; the inverted repeat sequence containing fragments of the VInv gene derived from S. tuberosum var. Ranger Russet; and the promoter for the granule-bound starch synthase (pGbss) gene (in the reverse orientation) derived from S. tuberosum var. Ranger Russet. The pSIM1678 T-DNA construct was used to transform the Generation 1.0 Simplot Innate® potato events Gen1-E56 (not previously assessed by Health Canada) into the Generation 2.0 event Gen2-W8, and the previously assessed Generation 1.0 events Gen1-F10 and Gen1-J3 into Generation 2.0 events Gen2-X17 and Gen2-J3, respectively.

Simplot Innate® potato events Gen2-W8, Gen2-X17, and Gen2-Y9 were developed using Agrobacterium-mediated transformation of 4-week old potato internode segments (of 4 to 6 mm) using the transformation plasmids pSIM1278 (containing the pSIM1278 T-DNA construct) and pSIM1678 (containing the pSIM1678 T-DNA construct).

3. Characterization of the Modified Plants

Integrity and copy number of the pSIM1278 and pSIM1678 T-DNA inserts within events Gen2-W8, Gen2-X17, and Gen2-Y9 was characterized using Southern blot analysis and complemented by several DNA sequencing techniques (i.e. Sanger, Illumina, and PacBio) where necessary to elucidate specific sequences within each insert. The analysis began with the initial assumption that the pSIM1278 and pSIM1678 T-DNA constructs had inserted into the recipient genome in an identical manner to its sequence in their respective vectors (i.e., a simple insert structure). Based on this assumption, several restriction enzyme digests were performed using sets of probes specific to the elements within each T-DNA insert (i.e., ASN, GBS, AGP, R1, INV, and VNT1) to detect the presence of these elements. The observed band products were compared by size, intensity, and number to the expected band products (based on the simple structure assumption). Where the observed bands suggested a simple insert structure, Illumina whole genome sequencing was used to confirm the insert sequence and verify sequence and verify sequence coverage across the simple insert. Where the observed bands did not match the expected bands based on the simple structure assumption, further restriction enzyme digests were performed to refine the predicted insert sequence. In these cases, Illumina and PacBio sequencing methods were used in conjunction to verify sequence coverage across the complex insert and determine the sequence of any rearrangements in the insert.

Furthermore, Southern blot analysis confirmed an absence of the pSIM1278 and p1678 plasmid backbone sequences in the event Gen2-W8, Gen2-X17, and Gen2-Y9 genomes.

The potato is a vegetatively propagated crop and reproduction does not involve meiosis. Thus, the T-DNA insertions within Simplot Innate® potato events Gen2-W8, Gen2-X17, and Gen2-Y9 were expected to be genetically stable. Nevertheless, stability of the T-DNA inserts was confirmed over multiple propagations of each event by Southern blot analysis.

4. Product Information

Simplot Innate® potato events Gen2-W8, Gen2-X17, and Gen2-Y9 differ from their traditional counterparts by the addition of three inverted repeat sequences containing sequence fragments of 5 endogenous genes (i.e., Asn1, Ppo5, PhL, R1, and VInv), and the converging promoters (i.e., pAgp and pGbss) that drive their expression. Expression of these inverted repeat sequences results in the reduced level of mRNA (and subsequently expressed proteins) for those same genes using the RNA interference (RNAi) pathway of the host plant. Reduction in the protein expression of Asn1, Ppo5, PhL, R1, and VInv (for individual functions see Section 2: Development of the Modified Plants) results in reduced levels of asparagine and reducing sugars (i.e., glucose and fructose) in tubers as well as lower levels of the Ppo5 enzyme. The reduction in asparagine alone significantly decreases acrylamide formation in tubers when subjected to various forms of thermal processing (e.g., baking, frying, etc.). Lower levels of reducing sugars further decreases acrylamide formation and limits heat-induced browning. Reducing levels of the Ppo5 enzyme results in a decreased occurrence of black spot bruising in tubers. These events also express the R-protein, VNT1, which confers resistance to the late blight-causing pathogen P. infestans.

The host organism, Solanum tuberosum (potato), is produced in all provinces and territories of Canada and is an integral part of the world’s food supply. Many varieties of this species have a long history of safe use as food. Simplot Innate® potato events Gen2-W8, Gen2-X17, and Gen2-Y9 contain genomic DNA sequences derived from conventional potato and a wild potato species (Solanum verrucosum and Solanum venturii). According to the Organization for Economic Cooperation and Development (OECD), S. verrucosum is an acceptable source of genetic material used to improve potato varieties and has a history of safe food use. S. venturii is a wild potato species from Argentina and is a model system for virus-induced gene silencing studies. The use of genetic material from all three sources in Simplot Innate® potato events Gen2-W8, Gen2-X17, and Gen2-Y9 would not be expected to pose a safety concern.

With exception of the VNT1 protein, the T-DNA inserts present in Simplot Innate® potato events Gen2-W8, Gen2-X17, and Gen2-Y9 do not result in the expression of novel protein, but rather the expression of dsRNA molecules that are further processed by the endogenous enzyme Dicer into small siRNAs that will subsequently activate the RNAi pathway, resulting in reduced levels of the mRNA transcripts for five endogenous proteins (i.e., Asn1, Ppo5, PhL, R1, and VInv). As such, mRNA transcript levels (rather than protein concentrations) were evaluated to link new phenotypic traits in Simplot Innate® potato events Gen2-W8, Gen2-X17, and Gen2-Y9 to changes at the molecular level. RNA was isolated from various tissues of Simplot Innate® potato events Gen2-W8, Gen2-X17, and Gen2-Y9 and their untransformed counterparts and used to carry out Northern blot analyses.

Based on the Northern blot analyses, it was demonstrated that mRNA transcript levels for the five target genes were mostly reduced in tubers, the primary target tissue. This was expected as the promoters (i.e., pAgp and pGbss) express primarily in tubers. Reduced transcript levels in the other tissues were observed for each event (i.e. Asn1 levels in flower tissue, event Gen2-W8; Asn1 in leaf tissue and VInv in flower tissue, event Gen2-X17; and Asn1 in leaf and flower tissue and VInv in flower tissue, event Gen2-Y9). This pattern of RNAi-based down-regulation is similar to what was observed for previously assessed Simplot Innate® potato events Gen1-E12, Gen1-F10, Gen1-J3, Gen1-J55, and Gen1-V11 (Health Canada, 2016).

R-proteins are expressed at low levels in plants and in some cases are estimated to be as low as 18 ppt^{Footnote 1} . The VNT1 protein was detected in the tissues of these events when measured with a western blot assay sensitive to less than 280 ppb.

5. Dietary Exposure

It is expected that Simplot Innate® potato events Gen2-W8, Gen2-X17, and Gen2-Y9 will be used in applications similar to conventional potato varieties. A significant change in the food use of potatoes with the introduction of these transformed events is not anticipated.

6. Nutrition

The petitioner submitted data from field trials (2012-2014 growing seasons) conducted in potato growing areas of the United States (site locations similar to Canadian potato production regions). Each site used a randomized complete block design with 3 or 4 replicates per line. Event Gen2-W8 and its parental control Russet Burbank, were grown at 11 sites; Event Gen2-X17 and its parental control Ranger Russet, were grown at 8 sites; Event Gen2-Y9 and its parental control Atlantic, were grown at 7 sites.

The nutritional and compositional assessment of Simplot Innate® potato events Gen2-W8, Gen2-X17, and Gen2-Y9, their respective controls, and reference potato varieties included: proximates (i.e. moisture, protein, total fat, ash, crude fibre, carbohydrate, and calories), vitamins (i.e., vitamins B3, B6, and C), minerals (i.e. copper, magnesium, and potassium), total amino acids as well as free amino acids (i.e., asparagine, aspartic acid, glutamine, and glutamic acid), glycoalkaloids, and reducing sugars.

The petitioner provided summaries and detailed information on comparisons of the nutrient composition of tubers from the Simplot Innate® potato events Gen2-W8, Gen2-X17, and Gen2-Y9 and the respective controls as per the recommendations of the 2002 Organization for Economic Co-Operation and Development (OECD) Consensus Document on Compositional Considerations for New Varieties of Potatoes.  In addition to protein content, the petitioner provided the total and free amino acid concentrations due to its relevance to the transformed events. In addition to the OECD recommended vitamin C analysis, the petitioner provided data on vitamin B3 and B6, as well as the content of copper, magnesium, and potassium.

Statistical differences were observed in the following analytes in Simplot Innate® potato event Gen2-W8 (vitamin B6, vitamin C, and amino acid profile), event Gen2-X17 (crude fibre, vitamin C, and potassium), and event Gen2-Y9 (protein crude fibre, carbohydrates, calories, and potassium). All analyte levels fell within the ranges of those analytes in the reference varieties and/or literature ranges in conventional potatoes, including the OECD (2002) document for new varieties of potatoes.

The intended effects on levels of nutrients in event Gen2-W8, Gen2-X17, and Gen2-Y9 potatoes are reductions in the content of asparagine and the reducing sugars glucose and fructose, to reduce acrylamide formation during high-temperature processing (e.g. the production of fries and chips). The level of asaparagine in these events, although statistically lower than their parental controls, is within the ranges found in the reference varieties. The levels of reducing sugars in events Gen2-W8, Gen2-X17, and Gen2-Y9 were lower than the controls and reference varieties however they were within the range reported in the scientific literature.

The intended changes in amino acids are accompanied by certain predictable changes in other amino acids. An increase in glutamine is a direct result of a reduction in the expression of the Asn1 gene that codes for the asparagine synthetase enzyme that converts aspartate to asparagine. Concomitantly, due to the lower asparagine levels, there were small but significantly higher levels of some amino acids in event Gen2-W8 (alanine, cysteine, glutamic acid/glutamine, glycine, leucine, proline, threonine, and tyrosine), in event Gen2-X17 (alanine, arginine, cysteine, glutamic acid/glutamine, glycine, isoleucine, leucine, lysine, methionine, phenylalanine, proline, serine, threonine, tyrosine, and valine), and event Gen2-Y9 (alanine, arginine, cysteine, glutamic acid/glutamine, glycine, histidine, isoleucine, leucine, phenylalanine, proline, serine, threonine, tryptophan, tyrosine, and valine) when considered as a percent of the total amino acids, with glutamine being the highest. The levels of amino acids are within the ranges found in reference varieties and would not present a nutritional concern.

Reducing the expression of the Ppo5 gene that codes for the polyphenol oxidase-5 enzyme, for the purpose of reducing the oxidation of polyphenols to precipitated dark pigments, may have additional effects. Literature information suggests that reduced polyphenol oxidase activity could reduce degradation of antioxidant polyphenols and reduce production of potentially toxic plant defense compounds such as quinones. Thus, these unmeasured but plausible unintended effects are unlikely to pose any increased nutritional risk and could be beneficial.

Except for the intended changes, the petitioner has sufficiently demonstrated that Simplot Innate® potato events Gen2-W8, Gen2-X17, and Gen2-Y9 tubers have similar compositions compared to their unmodified controls and therefore would not pose an increased nutritional risk to consumers.

7. Chemistry/Toxicology

Simplot Innate® potato events Gen2-W8, Gen2-X17, and Gen2-Y9 contain the same genetic insert (pSIM1278 T-DNA) as the previously approved Simplot Innate® potato events Gen1-E12, Gen1-F10, Gen1-J3, Gen1-J55, and Gen1-V11 which were found to be as safe as conventional potato varieties. Safety data for the RNAi elements that are common between these potato events (which target potato Asn1, R1, PhL, and Ppo5 mRNA) was bridged from these previous evaluations (Health Canada, 2016).

The assessment of events Gen2-W8, Gen2-X17, and Gen2-Y9 focused on the novel traits which were not previously reviewed for safety. This included the S. venturii VNT1 protein (Rpi-vnt1) and the small interfering RNA (siRNA) which target endogenous vacuolar invertase (VInv) expression.

The event Gen2-W8, Gen2-X17, and Gen2-Y9 potatoes contain DNA sequences derived from conventional potato (Solanum tuberosum) or wild potato (Solanum venturii).  S. venturii is a wild potato that originated from South America (Argentina) and does not have a history of use as a food. However, the petitioner stated that the Rpi-vnt1 gene that was cloned from S. venturii is identical in nucleotide sequence to the Rpi-Phu1 gene that is expressed in Solanum phureja, a wild potato that is used in potato breeding programs for food use in Europe and South America. Evaluators considered that the use of a common genetic element from S. venturii and S. phureja would not pose a toxicological concern.

The petitioner stated that the siRNAs generated by the event Gen2-W8, Gen2-X17, and Gen2-Y9 potatoes would not be bioavailable. They reasoned that most of the siRNAs would be degraded during cooking or digested when consumed. They also stated that siRNAs would be largely prevented from reaching target tissues due to numerous biological barriers that exist in the human body. No data were provided to directly support this position, however, it is considered plausible on a chemical and biological basis.

The petitioner demonstrated that all potential siRNA sequences derived from the Vlnv RNAi inverted sequence do not share perfect sequence complementarity with human transcripts (NCBI refseq_rna database;12 216 199 sequences) or protein-coding sequences in the human genome (163 241 sequences; human genome published by the University of California Santa Cruz).  These data support the position that the siRNAs are not expected to have an off-target effect, such as silencing of human mRNAs, and therefore would not be expected to create a hazard.

The sequence that encodes Rpi-vnt1 is under the control of the native Rpi-vnt1 promoter and terminator sequence derived from S. venturii. It is expected that VNT1 protein expression would be low, consistent with that reported in the literature for S. venturii. The low level of VNT1 expression in event W8, X17, and Y9 potato tubers was confirmed by western blot analysis (< LOQ = 280 ppb). Even with the use of highly conservative estimates for potato dietary intake, assuming levels of VNT1 expression at the level of quantitation, and neglecting the likelihood of denaturing and degradation of the protein through processing (i.e., cooking), VNT1 exposure in the greatest consumers of potatoes (i.e., children 1 year of age) is anticipated to be low (0.08 µg VNT1/kg body weight/day).

The petitioner provided three sub-chronic (90-day) oral toxicity studies in rats to assess the potential toxic effects of events Gen2-W8, Gen2-X17, and Gen2-Y9. In general, these studies were compliant with OECD Test guidelines and Good Laboratory Practice (GLP). Groups of 12 male and 12 female Crl:CD (SD) rats were provided potato powder (Gen2-W8, Gen2-X17, Gen2-Y9, Russet Burbank, Ranger Russet, or Atlantic potatoes) at a constant dietary concentration of 20% in the diet (by dry weight) and allowed to feed ad libitum for 90 days.

All animals survived to scheduled sacrifice. Minor statistically significant variations were observed in organ weights, hematology, and urinary parameters. These were not considered toxicologically relevant because event Gen2-W8, Gen2-X17, and Gen2-Y9 potatoes all express the same genetic elements but none of the observed variations were consistently observed when compared to the control animals. None of the observed effects were attributed to the RNAi and transgene products that are present in the genetically modified potatoes. It was concluded that under the study’s conditions, the event Gen2-W8, Gen2-X17, and Gen2-Y9 potatoes did not pose a toxicological concern.

The predicted amino acid sequence of the VNT1 protein was compared to sequences of known toxins retrieved from the National Center for Biotechnology Information Database (NCBI; 3 918 069 sequences annotated as ‘toxin’; E-value < 10-2).  VNT1 protein shared amino acid sequence homology with other resistance proteins (R-proteins in plants or insect resistance proteins sharing 15-22% sequence identity); none of these resistance proteins are established food toxins. The petitioner concluded that due to the low level of sequence homology, the VNT1 protein was considered not pose a toxicological concern.

The levels of glycoalkaloids, an endogenous toxin naturally present in potatoes, were present in event Gen2-W8, Gen2-X17, and Gen2-Y9 potatoes at levels consistent with conventional potatoes and were not considered to pose a toxicological concern.

The petitioner stated that the RNAi constructs in the event Gen2-W8, Gen2-X17, and Gen2-Y9 potatoes do not produce any novel proteins as all the RNA products that will be translated from these transgenes will be processed into siRNA. As such, the RNAi constructs in event Gen2-W8, Gen2-X17, and Gen2-Y9 potatoes will not produce novel allergens and would not pose an allergenic risk to consumers.

The predicted amino acid sequence of the VNT1 protein was compared with those of known allergens retrieved from the AllergenOnline database (E-value < 10-4; version 16; 1956 sequences; University of Nebraska) using the FASTA alignment algorithm. The VNT1 protein did not share significant amino acid identity (i.e., > 35% identity over 80 amino acids or E-value < 10-4) with known allergens that may be harmful to human health. Further, VNT1 does not contain potential allergen epitopes as determined by an 8-amino acid segment analysis. The bioinformatics search suggests that VNT1, based on protein sequence alone, does not match any known food allergen.

Patatin is an endogenous allergen found in conventional potatoes. It is a major storage protein and contributes to over 30% of the soluble protein in potato tubers. There is no evidence to suggest that patatin levels are increased in the genetically modified potatoes as compared to conventional potatoes, as suggested by the mean values for total amino acids in event Gen2-W8, Gen2-X17, and Gen2-Y9 potatoes, which were within range of historical controls.

Based on the available data regarding the toxicological and allergenic potential of Simplot Innate® potato events Gen2-W8, Gen2-X17, and Gen2-Y9, these potatoes are considered to be as safe as conventional potato varieties currently available in the Canadian marketplace from the perspective of toxicological and allergenic risk.

CONCLUSION:

Health Canada’s review of the information presented in support of the food use of Simplot Innate® potato events Gen2-W8, Gen2-X17, and Gen2-Y9 does not raise concerns related to food safety. Health Canada is of the opinion that food derived from these transformed events is as safe and nutritious as food from current commercial potato varieties.

Health Canada's opinion deals only with the food use of Simplot Innate® potato events Gen2-W8, Gen2-X17, and Gen2-Y9. Issues related to its use as animal feed have been addressed separately through existing regulatory processes in the Canadian Food Inspection Agency (CFIA).

This Novel Food Information document has been prepared to summarize the opinion regarding the subject product provided by the Food Directorate, Health Products and Food Branch, Health Canada. This opinion is based upon the comprehensive review of information submitted by the petitioner according to the Guidelines for the Safety Assessment of Novel Foods.

For further information, please contact:

Novel Foods Section
Food Directorate                                                                     
Health Products and Food Branch                                           
Health Canada, PL2204A1
251 Frederick Banting Driveway
Ottawa, Ontario K1A 0K9
novelfoods-alimentsnouveaux@hc-sc.gc.ca