GM Crop Database

Database Product Description

EH92-527-1 (BPS-25271-9)
Host Organism
Solanum tuberosum (Potato)
Trade Name
Amflora®
Trait
Altered starch composition, increased amylopectin to amylose ratio
Trait Introduction
Agrobacterium tumefaciens-mediated plant transformation.
Proposed Use

Production for industrial use and animal feed.

Product Developer
BASF Plant Science

Summary of Regulatory Approvals

Country Food Feed Environment Notes
European Union 2010 2010 2010

Summary of Introduced Genetic Elements Expand

Code Name Type Promoter, other Terminator Copies Form
gbss granule-bound starch synthase PQ genomic gbss fragment (Pgbss) functional as a promoter in plants A. tumefaciens nopaline synthase (nos) 3'-untranslated region 2 (partial) Truncated, antisense RNA interference
nptII neomycin phosphotransferase II SM nopaline synthase (nos) from A. tumefaciens A. tumefaciens nopaline synthase (nos) 3'-untranslated region 2 Native

Characteristics of Solanum tuberosum (Potato) Expand

Center of Origin Reproduction Toxins Allergenicity

South America, particularly the high plateau region of Bolivia and Peru

Only hybridizes with tuber forming Solanum species, which tend to be geographically separated from regions of potato cultivation

The glycoalkaloids, solanine and chaconine, are only known natural toxicants

No significant, reported allergens

Donor Organism Characteristics Expand

Latin Name Gene Pathogenicity
Solanum tuberosum gbss

The gbss gene fragment sequences introduced to suppress endogenous GBSS expression have no homology with known toxins.

Modification Method Expand

Potato event EH92-527-1 was developed by Agrobacterium tumefaciens-mediated transformation of the cultivar Prevalent. T-DNA, from plasmid pHoxwG, derived from pBIN19, was delivered to leaf discs using a binary vector system. The introduced DNA included the nptII gene derived from the Tn5 transposon of Escherichia coli under the control of the nopaline synthase (nos) promoter and terminator, and a potato genomic gbss fragment oriented in the antisense direction, under the control of its own promoter and the nos terminator. The endogenous potato gbss gene encodes for granule-bound starch synthase (GBSS), an enzyme which is responsible for amylose biosynthesis. RNA transcription from the antisense gbss construct leads to a reduction in expression of the endogenouts potato gbss gene. nptII encodes neomycin phosphotransferase II, an enzyme that inactivates aminoglycoside antibiotics such as kanamycin, neomycin, and geneticin and was used as a selectable marker to identify transformed plants.

Characteristics of the Modification Expand

The Introduced DNA

EH92-527-1 contains a single insert. DNA sequences towards the left border region of the T-DNA were deleted and the entire T-DNA insert, including the flanking region, was duplicated in reverse orientation. The insert includes the 5' untranslated region of the nopaline synthase gene (Pnos), the nptII coding sequence, the 3' untranslated part of the nopaline synthase gene, the potato gbss promoter fragment, and a truncated gbss coding region in antisense orientation without the terminator. The insert, together with the potato flanking region, was duplicated in a tail-to-tail arrangement with the two right border regions as junctions to the potato chromosomal DNA. Southern blot analyses indicated that no vector backbone sequences were inserted into potato EH92-527-1. No other unknown DNA sequences have been recombined into the inserted T-DNA.

Genetic Stability of the Introduced Trait

The stability of the inserted DNA in potato EH92-527-1 was assessed over several cycles of vegetative propagation via cuttings and tubers. The inserted trait was found to be stable over multiple generations based on compositional analyses of tuber starch from EH92-527-1. Southern blot analyses demonstrated that genomic DNA isolated in 1998 and 2005 had similar hybridization patterns with four different restriction enzyme combinations.

Expressed Material

The antisense orientation of the introduced gbss gene relative to the gbss promoter leads to a decrease in amylose content and an associated increase in amylopectin content. In conventional potato starch, the GBSS protein represents approximately 80% of the extractable protein; in EH92-527-1, the GBSS protein was not detectable.

NPTII protein expression was analyzed in leaves, tubers, pulp and starch. NPTII levels were 0.00082% of the soluble protein in pulp (8.2 ng/mg total protein; 55 ng/g fresh weight) and 0.0006% in tubers (6.82 ng/mg protein; 31 ng/g fresh weight). NPTII was much lower in leaves and undetectable in starch.

Environmental Safety Considerations Expand

Field Testing

The agronomic and compositional characteristics of EH92-527-1 were compared with those of the parental cultivar Prevalent in field trials carried out over multiple growing seasons in multiple locations in Sweden. Trial site locations were representative of the typical areas for cultivation of conventional starch potatoes. Data on agronomic characteristics were obtained from field trials during 1994-1996 and variety trials during 1996-1997. Compositional data were obtained from field trials during 1996-1998. No significant differences in growth characteristics between EH92-527-1 and Prevalent were observed nor were there any differences in susceptibility to herbicide, late blight fungal disease, and frost. Additionally, EH92-527-1 did not display altered susceptibility to insects, bacteria, other fungi, nematodes, and plant viruses.

Outcrossing

Potato is largely propagated vegetatively via tubers, but certain varieties can also form seeds. With regard to plant-to-plant gene transfer, the natural exchange of genetic material is only possible with other varieties of Solanum tuberosum. No natural genetic exchange has been detected with the potato's wild relatives in Europe, i.e., Solanum nigrum (deadly nightshade) and Solanum ducamara (woody nightshade). Efficient incompatibility barriers prevent hybridization between these species and Solanum tuberosum. Therefore, the chances of successful hybridization between transformed potatoes and other Solanum species under field conditions are considered extremely remote.

Any genetic spread is assessed as limited to cross-pollination with other potatoes. However, no changes in flower morphology have been observed for EH92-527-1 that could indicate a change in the ability to produce and release pollen. Therefore, no changes compared to conventional starch potatotes concerning the transfer of genetic material to other potato varieties is expected. The pollen production of flowers of EH92-527-1 is low and most of the flowers are shed before the pollen is ready. EH92-527-1 and Prevalent abort most flowers prematurely, and the stamen produce almost no pollen. This makes the probability of dispersal through pollen very low. Because the chance of any successful transfer is considered to be remote and would convey no selective advantage to any hybrid, the potential risk is considered to be extremely low. Therefore, the plant-to-plant gene transfer of the nptII and the antisense gbss genes is considered unlikely to be of environmental concern. Outside arable land, potato has a very low competitivelness, particularly in northern Europe, where the EH92-527-1 potatoes are intended to be cultivated.

With respect to plant-to-bacteria gene transfer, potato EH92-527-1 contains an nptII gene for kanamycin resistance that could theoretically be transferred from plant material to microbes in the soil. However, it is likely that cell DNA will be degraded by autolysis in any plant material left in the soil. Secondly, kanamycin resistance already occurs naturally in soil bacteria. Consequently, any additional contribution from potential transfer of nptII to soil microbes is considered insignificant.

Furthermore, studies show that a very large degree of homology is required between the plant's and the bacteria's DNA in order for horizontal gene transfer to take place at all in targeted studies. Under natural conditions, several other factors become important and these factors further limit the possibility for horizontal gene transfer that would result in a population of resistant bacteria. These factors include the absence of prokaryotic regulation sequences linked to nptII in the genetic construct in question and the need for selection pressure at the time of the gene transfer.
In addition, gene transfer of the antisense gbss construct is not considered to pose an environmental risk. Furthermore, as demonstrated by Southern analysis, no genetic elements outside of the right and left border region of the T-DNA in construct pHoxwG that could affect the mobility of DNA have been inserted into potato event EH92-527-1. Therefore, no changes as compared to conventional starch potatoes are expected in the ability of EH92-527-1 to transfer genetic material to bacteria.

Weediness Potential

Potato does not compete well outside the cultivated environment, but can survive mild winter temperatures as tubers in soil. The experimental data indicated that potato EH92-527-1 does not differ from its parent cultivar Prevalent with respect to frost tolerance, sensitivity to chemical treatment, and susceptibility to diseases and pests. No evidence was seen of increased competitiveness or over-winter survival that would indicate enhanced weediness or invasiveness of potato EH92-527-1. Outside the field, potato seedlings have difficulty becoming established, as they are at a competitive disadvantage relative to other plants. In general, the potato is not known as a colonizer of unmanaged ecosystems. It is not able to compete effectively with other species such as grasses, trees, and shrubs.
The potato's low competitiveness outside arable land is especially true in northern Europe where EH92-527-1 is planned to be grown. EG92-527-1 and Prevalent can be assumed to have even less long-term competitive ability, because they shed most flowers prematurely and produce very little pollen. In order for the potato to establish itself and spread outside the field in northern Europe, its competitive ability would have to increase significantly.

Secondary and Non-Target Adverse Effects

Data from field studies conducted in Sweden, Germany, and the Netherlands showed neither greater susceptibility nor greater resistance to pests (e.g., aphids, leafhoppers, potato cyst nematodes (sp. Globodera) and diseases (e.g., late blight (Phytophthora infestans), potato early blight (Alternaria solani), Erwinia rots) in potato EH92-527-1 versus non-GM potato lines. In addition, there was no evidence of changes in sensitivity to the plant-associated viruses PVY, PLRV, PMTV, and TRV.

It is believed that altered starch composition may have an effect on certain microorganisms, and that increased sugar content and reduced glycoalkaloid content might result in pests (e.g., insects) attacking the potato to a larger extent. However, several years of field trials on large areas under production conditions have not indicated any such differences. Furthermore, the levels of these substances are within the variation for conventional potatoes.
Also, the antibiotics resistance and the increased amounts of vitamin C content should not be able to affect non-target organisms.

While, theoretically, event EH92-527-1 could have effects on other organisms if it were to establish itself within natural plant populations, the parent cultivar Prevalent, which has not shown spreading ability significantly different from that of EH92-527-1, has not been able to establish itself outside arable land. In addition, factors that provide for low competitive ability in the long term are that both Prevantent and EH92-527-1 shed most of their flowers prematurely, and produce almost no pollen.

In view of these results and the equivalent composition of the GM potato plant, it is considered that no adverse effects on plant-associated organisms would be expected from cultivation of the potato EH92-527-1. Furthermore, due to the nature of the modified trait and to the equivalence of the agronomic traits of the GM potato relative to those of the non-GM parental line, it is considered that no adverse effects on the abiotic environment would be likely from cultivation of EH92-527-1.

Impact on Biodiversity

EH92-527-1 will be grown in the same regions of Europe in which starch potatoes are presently grown and it will be farmed using identical techniques. The demonstrated equivalency of the EH92-527-1 event to the parental variety Prevalent suggests that the growing of EH92-527-1 represents no greater risks to biodiversity than does the parental variety or do other starch potatoes. As noted earlier, cultivated starch potatoes do not grow well outside of the immediate cultivated area. Pollen movement from EH92-527-1 is like that of the parental variety and moves only very short distances, if at all. Considering this, together with the equivalency of EH92-527-1 to the parental variety, the effects on biodiversity in other habitats should be no different from those of other starch potatoes. In particular, both the starch component amylopectin and the NPTII protein have a safe history of use and do not engender any alteration in the interactions with the biotic environment as compared to the parental cultivar Prevalent.

Food and/or Feed Safety Considerations Expand

Dietary exposure

EH92-527-1 is not intended for food use. For this reason, a far-reaching quality assurance system has been established for keeping EH92-527-1 separate from other potatoes. This system, in combination with the innate characteristics of the potato, makes it very unlikely that EH92-527-1 will get into the food chain. However, the possibility cannot be completely ruled out.

Starch rich in amylopectin does not constitute a health risk to normal healthy individuals. However, the branched starch molecule (amylopectin) is digested more quickly than the non-branched starch molecule (amylose), and this could result in undesirable effects for diabetics. It is therefore important that EH92-527-1 be kept well separated from other potatoes so as to avoid confusion with food potatoes. The observed difference in starch composition (from 85% amylopectin and 15 % amylose in Prevalent to 98% amylopectin and 2% amylose in EH92-527-1) is believed to be of no importance in cases of low or temporary intake.

EH92-527-1 produces only one new protein, NPTII, which has not been shown to be either toxic or allergenic.

The byproduct EH92-527-1 pulp, which is the material that remains after the starch has been extracted, will be used as bovine feed. As noted below, statistically significant differences in nutrient composition exist between EH92-527-1 and its parental cultivar Prevalent—in particular, with respect to higher levels of mono- and disaccharides, higher levels of vitamin C, and lower levels of glycoalkaloids. The measured differences fall within the natural variation interval for potatoes and are deemed to be of little significance. The feed product is considered to be substantially equivalent to the corresponding non-GM product and consequently no health risk is believed to exist.

Nutritional data

The analyzed compounds with regard to composition included dry matter, protein, fat, ash, carbohydrates, fiber, digestive fiber, fructose, glucose, sucrose, starch, chlorogenic acid, solanine, chaconine, nitrate, vitamin C, and minerals (Na, K, Ca, Mg, P, Fe, Zn, Cu, Mn, Cd). Composition data were obtained from field trials performed in 1996-1998. In addition to the intended differences in starch composition, some statistically significant differences were observed each year between EH92-527-1 and its parental cultivar Prevalent. These differences included decreases in yield and dry matter and increases in sucrose content and vitamin C content. Additional data on potato EH92-527-1 tested during starch production trials in 1998-2000 showed similar values for yield compared with equivalent potato cultivars. Although additional differences were noted during single years, these were not consistently noted through three years. These differences included decreases in glycoalkaloid levels (solanine and chaconine) in potato EH92-527-1 during two years. The changes in vitamin C and glycoalkaloids were within the background ranges reported in the literature. The change in sucrose content was considered as being related to the intended alteration of starch biosynthesis. It should be noted that nitrates are found in the entire plant and are considered anti-nutritional. It was concluded that the observed differences are unlikely to cause adverse health effects. In addition, analyses of the gross and mineral compounds of pulp and juice derived from potato EH92-527-1 and the non-transgenic cultivar Prevalent showed that their compositions were similar. Taken together, the characteristics of the EH92-527-1 potato, its compositional characteristics due to the introduced trait, the anticipated intake and exposure and the presence and safe use of the starch component amylopectin in the food supply, the EH92-527-1 event is considered to pose negligible risk to human health.

Toxicity

The main toxic or anti-nutritional substances in potatoes are glycoalkaloids and nitrates. Glycoalkaloids, which are toxic in high concentrations, are found in harmful amounts chiefly in the above-ground parts of the plant (e.g., stems, leaves, and fruits). Nitrates are found in the entire plant and are considered anti-nutrients.

As noted earlier, statistically significant changes in nutrient composition exist between EH92-527-1 and its parental cultivar Prevalent—in particular, with respect to higher levels of mono- and disaccharides, higher levels of vitamin C, and lower levels of glycoalkaloids. The measured differences fall within the natural variation interval for potatoes and are deemed to be of little significance.

A total of eighteen open reading frames (ORFs) have been identified in the insert sequence of the potato EH92-527-1. Eleven of these have no sequence homology with known coding regions. Bioinformatic analysis has shown that, for all ORFs identified, there are no homologies with known toxins or allergens.

The only ORF having a complete coding region for a known protein is the nptII gene. Bioinformatic analysis indicates that ORF4 could be transcribed due to its association with ORF1 (nptII). However, a translation start in the correct reading frame is absent and a stop codon is present before ORF4. The hypothetical ORF4 protein showed a high degree of similarity with two proteins that are not known to be toxic or allergenic. Furthermore, extensive studies indicated that, while OR4 transcript is detectable in the GM potato, there is no corresponding translation into protein. It is therefore concluded to be unlikely that the presence of ORF4 in EH92-527-1 would constitute a risk. No toxicity of the NPTII protein has been observed and in simulated digestive fluids this protein is rapidly degraded. In addition, two animal studies have indicated no adverse effects on animal health. A subchronic 90-day feeding study in rats with freeze-dried potatoes derived from EH92-527-1 and its parental line failed to reveal any effects that would raise concern about the transgenic potato. An eight-week nutritional animal feeding study with pulp derived from EH92-527-1 and conventional pulp fed to heifers provided evidence of nutritional equivalence and revealed no detrimental effects on animal health.

The gene sequences introduced to suppress GBSS expression have no homology with known toxins.

The weight of evidence from these studies, taken together, indicates that EH92-527-1 and derived products are no more likely to cause adverse effects on human and animal health than conventional potatoes in the context of the proposed uses.

The application and approval do not include food use, therefore no complete food evaluation has been performed. It is therefore very important that the EH92-527-1 potato be kept out of the food chain. A sophisticated quality-assurance system has been developed for keeping EH92-527-1 separate from other potatoes. It is believed that the combination of this program with the characteristics of the potato will make it extremely unlikely that EH92-527-1 will get into the food chain.

Allergenicity

EH92-527-1 produces only one new protein, NPTII, which has been shown not to be allergenic.

The hypothetical ORF4 protein showed a high degree of similarity with two proteins that are not known to be toxic or allergenic. In addition, when screened against a database of sequences of allergenic proteins, the ORF4 protein sequence does not show any similarities that are believed to be relevant or to raise concerns about potential allergenic risk.

Allergenicity of the whole crop could be increased as an unintended effect of the random insertion of the transgene in the genome of Prevalent, for example through qualitative or quantitative modifications of the pattern of expression of endogenous proteins. This issue does not appear relevant because potato is not considered a major allergenic food, and possible over-expression of any endogenous protein that is not known to be allergenic would be unlikely to alter the overall allergenicity of the whole plant. The same considerations also apply to exposure by inhalation during processing. Should the high amylopectin potato be inadvertently consumed, the data supporting its equivalence to the non-modified parent variety would indicate that it is no more of a potential allergen than the non-modified parent.

Links to Further Information Expand


This record was last modified on Tuesday, July 22, 2014