GM Crop Database

Database Product Description

MON-88Ø17-3 (MON88017)
Host Organism
Zea mays L. (Maize)
Trait
Glyphosate herbicide tolerance and resistance to corn root worm (Coleoptera, Diabrotica sp.).
Trait Introduction
Agrobacterium tumefaciens-mediated plant transformation.
Proposed Use

Production of Z. mays for human consumption (wet mill or dry mill or seed oil), and meal and silage for livestock feed. These materials will not be grown outside the normal production area for corn.

Product Developer
Monsanto Company

Summary of Regulatory Approvals

Country Food Feed Environment Notes
Argentina 2010 2010 2010
Australia 2006
Canada 2006 2006 2006 View
China 2007 2007 View
Colombia 2011
European Union 2009 2009
Japan 2006 2006 2006
Korea 2006 2006
Mexico 2006 2006
Philippines 2006 2006
Taiwan 2006
United States 2005 2005 2005

Introduction Expand

Maize line MON88017 was genetically modified to contain two novel genes, cry3Bb1 for insect resistance, and cp4 epsps, which confers tolerance to glyphosate. Both genes were introduced into the parental maize line LH198 by Agrobacterium-mediated plant transformation.

The cry3Bb1 gene, isolated from the soil bacterium Bacillus thuringiensis (Bt) subspecies kumamotoensis, produces the insect control protein Cry3Bb1, a delta-endotoxin. Cry proteins, of which Cry3Bb1 is only one, act by selectively binding to specific sites localized on the lining of the midgut of susceptible insect species. Following binding, pores are formed that disrupt midgut ion flow, causing gut paralysis and eventual death due to bacterial sepsis. Cry3Bb1 is lethal only when eaten by the larvae of coleopteran insects (i.e., beetles), and its specificity of action is directly attributable to the presence of specific binding sites in the target insects. There are no binding sites for the delta-endotoxins of B. thuringiensis on the surface of mammalian intestinal cells, therefore, livestock animals and humans are not susceptible to these proteins. The Cry3Bb1 protein expressed in MON88017 provides protection against the western corn rootworm (Diabrotica vigifera) and northern corn rootworm (Diabrotica barberi).

MON88017 also was developed to allow the use of glyphosate, the active ingredient in the herbicide Roundup®, as a weed control option. The novel plants express an herbicide tolerant form of the enzyme 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) derived from the common soil bacterium, Agrobacterium tumefaciens strain CP4. Glyphosate specifically binds to and inactivates EPSPS, which is involved in the synthesis of the aromatic amino acids, tyrosine, phenylalanine and tryptophan (shikimate biochemical pathway). EPSPS is present in all plants, bacteria, and fungi but not in animals, which must obtain these essential amino acids from their diet. Because the aromatic amino acid biosynthetic pathway is not present in mammalian, avian or aquatic life forms, glyphosate has little if any toxicity for these organisms (U.S. EPA, 1993; WHO, 1994; Williams et al. 2000). The EPSPS enzyme is normally present in food derived from plant and microbial sources.

Summary of Introduced Genetic Elements Expand

Code Name Type Promoter, other Terminator Copies Form
cry3Bb1 Cry3Bb1 delta-endotoxin IR CaMV 35S promoter with duplicated enhancer region 5' UTR from wheat chlorophyll a/b-binding protein; rice actin gene first intron 3' UTR from wheat heat shock protein (tahsp17 3') 1 functional synthetic
CP4 epsps 5-enolpyruvyl shikimate-3-phosphate synthase HT rice actin I promoter and intron sequences chloroplast transit peptide from A. thaliana A. tumefaciens nopaline synthase (nos) 3'-untranslated region 1 functional

Characteristics of Zea mays L. (Maize) Expand

Center of Origin Reproduction Toxins Allergenicity

Mesoamerican region, now Mexico and Central America

Cross-pollination via wind-borne pollen is limited, pollen viability is about 30 minutes. Hybridization reported with teosinte species and rarely with members of the genus Tripsacum.

No endogenous toxins or significant levels of antinutritional factors.

Although some reported cases of maize allergy, protein(s) responsible have not been identified.

Donor Organism Characteristics Expand

Latin Name Gene Pathogenicity
Bacillus thuringiensis subsp. kumamotoensis cry3Bb1 While coleopterans are susceptible to oral doses of Cry3Bb1 protein, there is no evidence of toxic effects in laboratory mammals or birds. There are no significant mammalian toxins or allergens associated with the host organism.
Agrobacterium tumefaciens strain CP4 CP4 epsps

A. tumefaciens is a common soil bacterium that is responsible for causing crown gall disease in susceptible plants. There have been no reports of adverse affects on humans or animals.

Modification Method Expand

MON88017 maize was produced by Agrobacterium-mediated transformation of the hybrid maize line LH198. The T-DNA segment of the vector plasmid PV-ZMIR39 contained sequences corresponding to a synthetic variant of the cry3Bb1 gene from Bacillus thuringiensis subsp. kumamotoensis strain EG4691 and the cp4 epsps gene from Agrobacterium tumefaciens strain CP4. Transcription of the cry3Bb1 gene was directed by the 35S promoter with a duplicated enhancer region from Cauliflower Mosaic Virus, the 5’ untranslated leader from the wheat chlorophyll a/b-binding protein, and was enhanced by the rice actin gene first intron. Terminator and polyadenylation sequences were derived from the 3’ untranslated region of the wheat heat shock protein (tahsp17 3’).

The cp4 epsps gene, which codes for the novel protein CP4 EPSPS, was joined to the chloroplast transit peptide gene (ctp2), isolated from Arabidopsis thaliana) to target the expression of the novel protein to the chloroplast. The expression of the cp4 epsps gene was regulated by the rice actin gene promoter and enhanced by the rice actin gene first intron. Terminator and polyadenylation sequences were derived the 3’ untranslated region of the nopaline synthase (NOS) coding sequence. The left border sequence (from octopine Ti plasmid pTi15955) and right border (from nopaline Ti plasmid pTiT37) contained non-coding sequences essential for the transfer of the T-DNA segment.

Characteristics of the Modification Expand

The Introduced DNA

Southern blot analysis of the genomic DNA of MON 88017 demonstrated the integration of a single, intact copy of the T-DNA of PV-ZMIR39. Both novel genes, cry3Bb1 and cp4 epsps, along with their respective promoter, enhancer and terminator sequences, were completely integrated. None of the vector backbone sequences, including the spectinomycin resistance and streptomycin resistance genes, were integrated into the genome of MON88017.

Genetic Stability of the Trait

The stability of both cry3Bb1 and cp4 epsps genes were assessed using Southern blot analysis and segregation analysis across 10 generations. The integration was shown to be stable across generations and the genes segregated according to a Mendelian inheritance pattern.

Environmental Safety Considerations Expand

Field Testing

Maize event MON88017 was field tested in Canada in 2003, and in the United States in 2001, 2002 and 2003. Agronomic characteristics of hybrids derived from MON88017 such as seed dormancy, vegetative vigour, early stand establishment, time to maturity, flowering period, susceptibilities to various pests and pathogens, and seed production were compared to those of unmodified counterparts. Nutritional components of MON88017, such as proximates, amino acids and fatty acids were compared with those of unmodified counterparts.

Outcrossing

Pollen production and viability were unchanged by the genetic modification resulting in MON88017, therefore pollen dispersal by wind and outcrossing frequency should be no different than for other maize varieties. Gene exchange between MON88017 and other cultivated maize varieties will be similar to that which occurs naturally between cultivated maize varieties at the present time. In the United States and Canada, where there are no plant species closely-related to maize in the wild, the risk of gene flow to other species appears remote. Feral species in the United States related to corn cannot be pollinated due to differences in chromosome number, phenology (periodicity or timing of events within an organism’s life cycle as related to climate, e.g., flowering time) and habitat.

Maize (Zea mays ssp. mays) freely hybridizes with annual teosinte (Zea mays ssp. mexicana) when in close proximity. These wild maize relatives are native to Central America and are not present in the United States, except for special plantings. Tripsacum, another genus related to Zea, contains sixteen species, of which twelve are native to Mexico and Guatemala. Three species of Tripsacum have been reported in the continental United States: T. dactyloides, T. floridanum and T. lanceolatum. Of these, T. dactyloides, Eastern Gama Grass, is the only species of widespread occurrence and of any agricultural importance. It is commonly grown as a forage grass and has been the subject of some agronomic improvement (i.e., selection and classical breeding). T. floridanum is known from southern Florida and T. lanceolatum is present in the Mule Mountains of Arizona and possibly southern New Mexico. Even though some Tripsacum species occur in areas where maize is cultivated, gene introgression from maize under natural conditions is highly unlikely, if not impossible. Hybrids of Tripsacum species with Zea mays are difficult to obtain outside of the controlled conditions of laboratory and greenhouse. Seed obtained from such crosses are often sterile or progeny have greatly reduced fertility.

Weediness Potential

The history and biology of maize indicates that non-transgenic plants of this species are not invasive in unmanaged habitats. Maize does not possess the potential to become weedy due to traits such as lack of seed dormancy, the non-shattering nature of corn cobs, and the poor competitive ability of seedlings. The data generated from field trials shows that MON88017 and derived hybrids are similar to their counterparts in this respect. Data submitted by the developer on the reproductive and survival biology of hybrids derived from MON88017 determined that early stand establishment, flowering period, vegetative vigor, time to maturity and seed production were within the normal range of expression of these traits currently displayed by commercial hybrids. No competitive advantage was conferred to MON88017, other than that conferred by resistance to rootworm and tolerance to glyphosate herbicide. These traits were demonstrated not to render maize weedy or invasive of natural habitats since none of the reproductive or growth characteristics were modified. The above considerations lead to the conclusion that MON88017 has no altered weed or invasive potential compared to currently commercialized corn.

Secondary and Non-Target Adverse Effects

The agronomic characteristics of MON88017 hybrids were shown to be within the range of values displayed by currently commercialized maize hybrids, and indicate that the growing habit of maize will not be inadvertently altered by cultivation of MON88017. Field observations did not indicate modifications of disease and pest susceptibilities, other than to rootworm, which is not known to be a principal factor restricting the establishment or distribution of maize.
Some of the genetic elements introduced into MON88017 were derived from known plant pathogens, but in all cases the genes responsible for the pathogenic qualities of the pathogen were not introduced. Therefore, the introduction of genetic material for Diabotica spp. resistance and glyphosate tolerance would not be expected to result in MON88017 expressing novel pathogenic characteristics.

The history of use and literature suggest that the bacterial Cry3Bb1 toxins are not toxic to humans, other vertebrates, and non-coleopteran invertebrates. This protein is active only against specific coleopteran insects. Data from dietary toxicity and field studies on the effect of the Cry3Bb1 protein on non-target organisms supported the environmental safety assessment of corn event MON863. In all cases, MON863 corn was demonstrated to be safe to non-target organisms. Given that MON88017 Cry3Bb1 protein differs from the MON863 CryBb1 protein by a single amino-acid, that both proteins were demonstrated to be equivalent in terms of insecticidal activity against susceptible pest insects and that the levels of Cry3Bb1 expression in both lines are similar, MON88017 is expected to be safe to previously assayed non-target organisms. The Cry3Bb1 protein expressed in MON88017 was also demonstrated to be safe to mammals.

The impact of CP4 EPSPS protein on non-target organisms, including humans, has been thoroughly assessed in previous applications for environmental safety assessments of CP4 EPSPS-expressing crops. The CP4 EPSPS protein expressed in MON88017 tissues is the same or is > 99% identical to CP4 EPSPS proteins produced in glyphosate-tolerant crops with a history of safe use. The environmental and feed safety of the CP4 EPSPS protein in corn has been previously established with, for example, the regulatory approval of NK603.

Non-transgenic maize is known to produce low levels of anti-nutrients such as raffinose and phytic acid, and the levels of these compounds in MON88017 were demonstrated to be equivalent to levels found in control lines. Therefore the genetic modification did not alter the expression of endogenous anti-nutritional factors.

Based on this data, it was determined that the unconfined release of MON88017 will not result in altered impacts when compared with currently commercialized corn on interacting organisms, including humans, with the exception of specific coleopteran pest species.

Impact on Biodiversity

MON88017 has no novel phenotypic characteristics which would extend its use beyond the current geographic range of maize production. Since maize does not out-cross to wild relatives in the united States or Canada, there will be no transfer of novel traits to unmanaged environments. In addition the novel traits were determined to pose minimal risks to non-target organisms.

MON88017 provides an alternative method to existing methods of control of rootworms, an important agricultural pest of maize. The control of agricultural pest species is a common practice that is not restricted to the environmental release of transgenic plants. Therefore, the reduction in local pest species as a result of the cultivation of MON88017 does not present a significant change from existing agricultural practices.

At present, the use of chemical insecticides to control rootworm is permitted, although crop rotation represents a major method of rootworm control ins some countries.

MON88017 also provides an alternative method of weed control in corn production. The use of broad spectrum herbicides has the intended effect of reducing local weed populations within agricultural fields and this may reduce local weed species biodiversity, and possibly other trophic levels which utilize these weed species. It must be noted, however, that reduction in weed biodiversity in agricultural fields is not unique to the use of transgenic plants, and is a common practice in virtually all modern agricultural systems. It was therefore concluded that MON88017 does not present a significantly altered impact on biodiversity in comparison to maize varieties currently being grown.

Food and/or Feed Safety Considerations Expand

Dietary Exposure

Humans consume relatively little whole kernel or processed maize, compared to maize-based food ingredients. Maize is a raw material for the manufacture of starch, the majority of which is converted to a variety of sweetener and fermentation products, including high fructose syrup and ethanol. Maize oil is commercially processed from the germ. These materials are components of many foods including bakery and dairy goods, and the human food uses of grain from MON88017 are not expected to be different from the uses of non-transgenic field maize varieties. As such, the dietary exposure to humans of grain from insect resistant hybrids will not be different from that for other commercially available field maize varieties.

Potential toxicity and allergenicity

The two novel proteins present in MON88017 corn have been assessed previously for safety; the CP4 EPSPS protein is present in approved lines of canola, cotton, soybean, potato and other corn events. Previous assessments have shown that CP4 EPSPS administered directly to animals at a high dose is not toxic, and the evidence indicates no potential for this protein to be allergenic in humans. Given its widespread use in approved glyphosate-tolerant crops, it now has a history of safe use in food over 10 years.

In considering the potential toxicity and allergenicity of the Cry3Bb1 variant protein, it is worth noting that Bt formulations containing Cry3Bb1 have been used safely in agriculture since 1995. Two separate acute toxicity studies in mice using the individual Cry3Bb1 variant proteins present in MON88017 and MON863 respectively confirmed the absence of mammalian toxicity in each case. Bioinformatic studies confirmed the absence of any significant amino acid similarity with known protein toxins and allergens, and in vitro digestibility studies demonstrated that Cry3Bb1 variants are rapidly degraded in the stomach following ingestion. Furthermore, processing involving heat treatment renders the Cry3Bb1 variant protein non-functional (i.e. unable to exert a toxic effect in insects). This weight of evidence indicates that the Cry3Bb1 variant protein is not toxic and is unlikely to pose an allergenic risk to humans.

Nutritional and Compositional Data

Forage and grain from MON 88017 maize, grown at three locations, were analyzed for nutritional composition and compared to that of a non-transgenic maize of similar genetic background (i.e., the conventional maize control), and to the composition of twelve conventional maize hybrids.

Forage was harvested at the late dough to early dent stages and was analyzed for proximates (crude protein, crude fat, moisture, ash and carbohydrate), acid detergent fibre, neutral detergent fibre, calcium and phosphorus. No significant differences in the levels of these components were observed between MON88017, the conventional control and the conventional hybrids.

Grain samples were obtained from mature (growth stage R6) plants harvested at three locations. The levels of several nutritional components were determined, including: proximates (crude protein, crude fat, moisture, ash, and carbohydrate); acid detergent fibre, neutral detergent fibre, total dietary fibre; minerals (calcium, phosphorus, magnesium, copper, iron, manganese, potassium, and zinc); amino acids; fatty acids; vitamins (folic acid, niacin, B1, B2, B6, and E); anti-nutrients (phytic acid, raffinose); and secondary metabolites (ferulic acid, p-coumaric acid).

Statistical analysis of the nutritional component data across all locations revealed no significant differences among MON 88017, the non-transgenic control, and the commercial hybrids, with the exception of levels of vitamin B1, and linolenic and arachidic acid, expressed as percentages of total fatty acids. The differences in linolenic and arachidic acids were not significant when the data was expressed on a dry matter basis. The levels of vitamin B1 were lower in MON 88017 compared to the non-transgenic control, but were within the 99% tolerance interval established using the twelve conventional commercial hybrids.

The levels of the antinutritional compounds phytic acid and raffinose, as well as the secondary metabolites ferulic acid and p-coumaric acid, were determined in the grain. Phytic acid occurs naturally in maize and other cereals. It is indigestible by humans and non-ruminant livestock, and also inhibits the absorption of iron and other minerals. Raffinose is an oligosaccharide found in cereals and legumes. It is cannot be digested by humans and monogastric livestock, thereby reducing the amount of metabolizable energy in foods and livestock feeds. Ferulic acid and p-coumaric acid are phenolic compounds found in cell walls; these become covalently linked to hemicelluloses during cell wall development. In ruminants, these compounds inhibit cell wall degradation by rumen microorganisms. No significant differences were observed in the levels of these antinutrients and secondary metabolites between MON 88017 and the non-transgenic control maize line. The levels of these compounds were also within the 99% tolerance interval established for the twelve conventional maize hybrids.

The results of these compositional analyses led to the conclusion that MON 88017 forage and grain is not different in nutritional and antinutritional composition compared to maize hybrids currently marketed, grown and consumed.

Abstract Collapse

Maize, or corn (Zea mays L.) is grown commercially in over 100 countries with a combined harvest of nearly 700 million metric tonnes in 2006. The top five producers of maize in 2005 were the United States, China, Brazil, Argentina, and Mexico, accounting for 70% of world production. Maize is grown primarily for its kernel (grain), the majority of which is used for animal feed, but with significant amounts refined into products used in a wide range of food, medical, and industrial goods.

Maize is a raw material for the manufacture of starch, the majority of which is converted by a complex refining process into sweeteners, syrups, and fermentation products, including ethanol. Maize oil is extracted from the germ of the maize kernel. Only a small proportion of the whole kernel is consumed by humans (e.g., corn meal, grits, oil), while refined maize products such as sweeteners, starch, and oil are abundant in processed foods (e.g., breakfast cereals, dairy goods, chewing gum). Maize is also processed into masa, which is used for tortillas, tacos and corn chips.

In the United States maize is typically used as animal feed, with roughly 70% of the crop fed to livestock, however a growing amount is now being used for the production of ethanol. The entire maize plant, the kernels, and several refined products such as glutens and steep liquor, are used in animal feeds. Silage made from the whole maize plant makes up 10-12% of the annual corn acreage, and is a major ruminant feedstuff. Livestock that feed on maize include cattle, pigs, poultry, sheep, goats, fish and companion animals.

Industrial uses for maize products include recycled paper, paints, cosmetics, car parts. Refined maize products are also used in bioproducts such as antibiotics.

Corn rootworm (Diabrotica spp.) is considered one of the most damaging insects pests of maize. The species of corn rootworm most prevalent in the United States are the northern corn rootworm (Diabrotica barberi) and the western corn rootworm (D. virgifera). The larvae of these beetles (coleopterans) feed on the corn roots. Feeding damage to the roots impedes the absorption of water and nutrients. Corn rootworms also feed on the brace roots and cause plant lodging. Adults feed on the silks thus interfering with pollination and seed set. Crop rotation is a recommended practice to reduce the population of these insects; thus, corn should not follow corn in a rotation. The protection offered by insecticides is limited: these will protect the crop from rootworm damage, but will only reduce a small percentage of the beetles from emerging.

Weeds are also a major production problem in maize cultivation. Typically, weeds are managed using a combination of cultural (e.g., seed bed preparation, clean seed, variety selection) and chemical controls. Depending on the production area and the prevalent weed species, herbicides may be incorporated into the soil before planting (pre-plant), applied after planting but before emergence (pre-emergence), or applied after the maize plants emerge (post-emergence). Ideally, for maize production, weeds should be controlled for the full season. However, the most critical period for weed control is usually about six to eight weeks after crop emergence, during the 4th to 10th leaf stages. This critical period in the life cycle of maize must be kept weed free in order to prevent yield loss.

The transgenic maize line MON 88017 was genetically engineered to resist the western corn rootworm (Diabrotica virgifera) and northern corn rootworm (D. barberi) by producing an insecticidal protein, and to express tolerance to the herbicide glyphosate. Two novel genes, a variant of the cry 3Bb1 gene and cp4 epsps, were introduced into the maize line LH198 using Agrobacterium -mediated transformation.

The cry3Bb1gene, isolated from the soil bacterium Bacillus thuringiensis (Bt) subspecies kumamotoensis strain EG4691, produces the insect control protein (delta-endotoxin) Cry3Bb1. Cry proteins, of which Cry3Bb1 is only one, act by selectively binding to specific sites localized on the lining of the midgut of susceptible insect species. Following binding, pores are formed that disrupt midgut ion flow, causing gut paralysis and eventual death due to bacterial sepsis. Cry3Bb1 is lethal only when eaten by the larvae of coleopteran insects (i.e. , beetles), and its specificity of action is directly attributable to the presence of specific binding sites in the target insects. There are no binding sites for the delta-endotoxins of B. thuringiensis on the surface of mammalian intestinal cells, therefore, livestock animals and humans are not susceptible to these proteins.

The cp4 epsps gene, isolated from Agrobacterium tumefaciens strain CP4, codes for a form of the enzyme 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) which is tolerant to glyphosate. The EPSPS enzyme is part of the shikimate pathway, an important biochemical pathway in plants involved in the production of aromatic amino acids and other aromatic compounds. When conventional plants are treated with glyphosate, the plants cannot produce the aromatic amino acids needed for growth and survival. EPSPS is present in all plants, bacteria, and fungi. It is not present in animals, which do not synthesize their own aromatic amino acids. Because the aromatic amino acid biosynthetic pathway is not present in mammals, birds or aquatic life forms, glyphosate has little if any toxicity for these organisms. The EPSPS enzyme is naturally present in foods derived from plant and microbial sources.

The food and livestock feed safety of MON 88017 maize grain and forage was established based on several standard criteria. As part of the safety assessment, the nutritional composition of MON 88017 grain was found to be equivalent to conventional maize as shown by the analyses of key nutrients including proximates (i.e. , moisture, crude protein, crude fat, ash and carbohydrates), acid detergent fibre, neutral detergent fibre, total dietary fibre, amino acid composition, fatty acid profiles, minerals (e.g. , calcium, phosphorus, magnesium), and vitamins (i.e., folic acid, niacin, vitamin E), as well as antinutrient compounds. Similar compositional analyses were conducted on MON88017 forage harvested at the late dough to early dent stages.

Links to Further Information Expand

Canadian Food Inspection Agency European Food Safety Authority Food Standards Australia New Zealand Health Canada Novel Foods Japanese Biosafety Clearing House, Ministry of Environment Philippines Department of Agriculture, Bureau of Plant Industry U.S. Environmental Protection Agency U.S. Food and Drug Administration U.S.Department of Agriculture, Animal and Plant Health Inspection Service

This record was last modified on Friday, March 26, 2010