GM Crop Database

Database Product Description

MON-ØØ863-5 (MON863)
Host Organism
Zea mays L. (Maize)
Trait
Resistance to corn root worm (Coleopteran, Diabrotica sp.)
Trait Introduction
Microparticle bombardment of plant cells or tissue
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
Australia 2003
Canada 2003 2003 2003
China 2004 2004
Colombia 2011
European Union 2006 2005 View
Japan 2002 2002
Korea 2003 2004
Mexico 2003 2003
Philippines 2003 2003
Taiwan 2003
United States 2001 2001 2003

Introduction Expand

Maize line MON 863 was produced using recombinant-DNA techniques to express the cry3Bb1 gene encoding a Coleopteran-specific insecticidal protein from Bacillus thuringiensis (subsp. kumamotoensis) in order to control infestation with corn root worm (CRW; Diabrotica sp.). This gene was introduced into the publicly available inbred line, A634, by particle acceleration (biolistic) transformation.

The cry3Bb1 gene encodes 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 Coleopteran species, including corn root worm, 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.

An antibiotic resistance marker gene (neo; synonym nptII) encoding the enzyme neomycin phosphotransferase II (NPTII), which inactivates aminoglycoside antibiotics such as kanamycin and neomycin, was also introduced into the genome of this transgenic maize. This gene was derived from a bacterial transposon (Tn5 transposable element from Escherichia coli) and was included as a selectable marker to identify transformed plants during tissue culture regeneration and multiplication. The expression of the nptII gene in these plants has no agronomic significance and the safety of the NPTII enzyme as a food additive was evaluated by the United States Food and Drug Administration in 1994 (US FDA, 1994).

Summary of Introduced Genetic Elements Expand

Code Name Type Promoter, other Terminator Copies Form
nptII neomycin phosphotransferase II SM CaMV 35S A. tumefaciens nopaline synthase (nos) 3'-untranslated region 1 The nptII cassette also contains 153 bp portion of bleomycin binding protein gene
cry3Bb1 cry3Bb1 delta-endotoxin IR 4-AS1 (single CaMV 35S plus four repeats of activating sequence) 5' untranslated leader sequence from wheat chlorphyll a/b binding protein, and rice actin intron 3' untranslated sequence of wheat heat shock protein 17.3 (tahsp17) 1 Addition of alanine residue at position 2 of protein

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.

Modification Method Expand

Maize line MON 863 was produced by biolistic transformation of the inbred line A634 (reportedly one of the most popular publicly available inbred lines used in hybrid maize production in the United States) using linearized plasmid PV-ZMIR13 DNA purified following Mlu I restriction endonuclease digestion. The introduced DNA contained the modified cry3Bb1 gene from B. thuringiensis subsp. kumamotoensis under the control of the 4-AS1 promoter (CaMV 35S promoter with 4 repeats of an activating sequence), plus the 5' untranslated leader sequence of the wheat chlorophyll a/b binding protein (wt CAB leader) and the rice actin intron. The transcription termination sequence was provided from the 3' untranslated region of the wheat 17.3 kD heat shock protein (tahsp17). The modified cry3Bb1 gene encodes a protein of 653 amino acids whose amino acid sequence differs from that of the wild-type protein by the addition of an alanine residue at position 2 and by seven amino acid changes.

The introduced DNA also contained a copy of the neomycin phosphotransferase II (NPTII) encoding gene (neo; synonym nptII) derived from the Tn5 transposon of Escherichia coli. This gene was introduced as a selectable marker under the control of the CaMV 35S promoter and the 3’ untranslated termination sequence (NOS 3’) from the Agrobacterium tumefaciens nopaline synthase gene. The nptII cassette also contained a 153 base pair portion of the bleomycin binding protein gene (ble; 378 bp total size).

Characteristics of the Modification Expand

The Introduced DNA

Southern blot analyses of genomic DNA from MON 863 demonstrated that there was a single site of integration containing one functional copy each of the modified cry3Bb1 and nptII genes and their associated regulated regulatory sequences. No deletions, truncations, or rearrangements were reported, nor were any additional plasmid-derived sequences detected.

Genetic Stability of the Introduced Trait

Segregation and stability of the introduced trait were examined by Southern blot analyses performed on genomic DNA extracted from plants spanning three generations, and by enzyme linked immunosorbent assay (ELISA) to detect expression of the Cry3Bb1 protein over five generations of progeny plants. These results demonstrated that the introduced trait continued to segregate as a single locus, and that protein expression remained stable over multiple generations.

Expressed Material

The levels of expression of Cry3Bb1 protein in various plant tissues, including young leaf, grain, mature root, forage, silk, and pollen, were measured by ELISA and were found to vary between 10 to 81 micrograms/g fresh weight of plant tissue, depending on the tissue type and the time of harvest. Expression of the NPTII protein was also confirmed in young leaf, forage, and grain, obtained from MON 863, with levels ranging from undetectable to 1.4 micrograms/g when measured by ELISA (limit of detection: <=0.076 micrograms/g).

Environmental Safety Considerations Expand

Outcrossing

The genetic insertion which resulted in MON 863 did not change its physiological characteristics of pollen production and pollen viability nor were there any changes in the plant’s sexual compatibility with other maize varieties. Pollen dispersal and outcropping frequency should be equivalent to that of untransformed maize lines, therefore gene exchange between MON 863 maize and other maize varieties will be similar to that which occurs between non-transformed lines. There are no wild relatives to maize in Canada or the United States, making gene flow to wild species extremely remote.

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 but are not present in Canada and 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. Tripsacum floridanum (Florida gamagrass) is native to the southern tip of Florida. Outcrossing with Tripsacum species is not known to occur in the wild and it is only with extreme difficulty that maize can be crossed with Tripsacum. The lack of compatible wild relatives in Canada and the maize –growing regions in the United States makes the possibility of gene flow into wild species in these areas very remote.

Weediness potential

The flowering period, vegetative vigour, time to maturity and seed production of MON 863 were within the normal range currently found in commercial maize hybrids. Maize does not possess the potential to become weedy due to traits such as a lack of seed dormancy, the non-shattering nature of maize cobs and the poor competitive ability of seedlings. Resistance to maize rootworm does not, in itself, render maize weedy or invasive of natural habitats as none of the reproductive or growth characteristics were modified. It was determined that it is very unlikely that MON863 would become a weedy pest of agriculture.

Secondary and Non-Target Adverse Effects

The Bt protein expressed in maize MON 863 (Cry3Bb1) was shown to be equivalent to microbial Bt used in sprays for over thirty years. The history of use and literature suggest that the bacterial Bt protein is not toxic to humans, other vertebrates and non-coleopteran invertebrates. This protein is active only against specific coleopteran insects. There are no coleopteran species listed as threatened or endangered in Canada or the United States.

Field studies indicated that MON863 did not have a negative effect on the abundance of non-target organisms compared to a non-Bt hybrid. Species studied included arthropods, earthworms and soil microbes. Coleopteran families including Carabidae, Staphylinidae and Coccinellidae were observed. Consideration was also given to the exposure of fireflies (family Lampyridae) to MON 863 since fireflies are coleopterans. It was concluded that the possibility of firefly exposure to Cry3Bb1 protein from MON 863 would be very unlikely as these insects generally do not occur sub-surface and do not feed on maize.

Feeding trials on non-target invertebrates, including honeybees, ladybird beetles, daphnia, collembola and earthworms, were also conducted. In addition, feeding trials were conducted on the non-target vertebrates such catfish and quail. MON 863 was demonstrated to be safe to these indicator species. MON 863 also did not demonstrate an increased level of anti-nutritional factors such as trypsin inhibitor and phytic acid when compared to unmodified control lines.

When compared with currently commercialized maize lines, MON 863 did not present an elevated risk to or impact on interacting organisms, including humans, with the exception of certain target coleopterans.

Potential Impact on Biodiversity

MON 863 has no novel characteristics that would extend its use beyond the current geographic range of maize production. Since the risk of outcrossing in the United States and Canada is remote, it was determined that the risk of transfer of novel traits to unmanaged environments was insignificant. The potential impact on biodiversity of MON 863 was judged to be equivalent to its unmodified counterparts.

Other Considerations

In Canada, the authorization for unconfined release into the environment and livestock feed use of MON 863 was limited to one year initially. Renewal of the one year authorization was conditional upon the submission of additional information requested by the CFIA. This additional information included a new beneficial insect study as the original study protocol for toxicity of the Cry3Bb1 protein to green lacewing larvae (Neuroptera: Chrysopidae) was not of an optimal design. The renewal of the permit was granted in 2004.

In addition, the use of MON 863 in unconfined releases is contingent upon the implementation of specific insect resistance management (IRM) plans in Canada and the United States. IRM strategies are required to prolong the effectiveness of plant-expressed Bt toxins and the microbial spray formulations of these toxins. These programs are mandatory for all transgenic Bt-expressing plants, including MON 863 maize, and require that growers plant a minimum of 20 percent of their acreage to non-transgenic varieties in order to reduce the potential for selecting Bt-resistant insect populations. The refuge acres must be planted adjacent to or within the Bt crop. Details on the specific design and requirements of individual IRM programs are published by the relevant regulatory authority.

Food and/or Feed Safety Considerations Expand

Dietary Exposure

In the United States and Canada, the primary form of consumption for field maize is as maize-based food ingredients with little whole kernel or processed field maize directly consumed by comparison. Field maize is used as a raw material for the manufacture of starch, which is in turn converted to a variety of sweeteners (such as high fructose maize syrup) and fermentation products (ethanol). The germ of the maize kernel is also used for the production of maize oil. These materials are commonly found in many foods, resulting in wide population dietary exposure to all maize products. The human food uses of grain from MON 863 are not expected to be different from the uses of non-transgenic field maize varieties and therefore the dietary exposure of the general population to MON 863 grain should not be different from that of other field maize varieties.

Nutritional Data

Compositional analyses were conducted on plant material (forage and grain) obtained from MON 863 and non-transgenic parental control plants grown at four replicated field trial sites in the United States. As a further comparison, similar analyses were conducted on plant material derived from nine different non-transgenic commercial maize hybrids grown under field conditions at two replicated sites.

Grain samples were analyzed for levels of protein, fat, ash, moisture, carbohydrates, acid detergent fibre (ADF), neutral detergent fibre (NDF), amino acids, fatty acids, vitamin E, minerals [calcium, copper, iron, magnesium (Mg), manganese (Mn), phosphorus (P), potassium, sodium, and zinc (Zn)], phytic acid, and trypsin inhibitor. Other than for the exceptions noted below, there were no statistical difference in the measured values for each of these parameters between MON 863 and the non-transgenic control line, and in each case the values obtained from both were within the range of values for the nine control varieties and those reported in the literature. The exceptions noted were:

  1. Carbohydrate levels and levels of the non-essential amino acids cysteine, aspartic acid, and glycine were higher in MON 863 than in the non-transgenic parental control, but were within the range of values measured for the nine commercial varieties.
  2. Levels of protein, the essential amino acids leucine and phenylalanine, and the non-essential amino acid glutamic acid, were lower in MON 863 than in the non-transgenic parental control, yet were within the range of values measured for the nine commercial varieties.
  3. The levels of P, Mg, Zn, Mn, and vitamin E were lower in MON 863 than in the non-transgenic parental control, but were within the range measured for the nine commercial varieties and those reported in the scientific literature.
  4. The level of phytic acid (a phosphorus-binding dietary antinutrient) was lower in MON 863 than in the non-transgenic parental control, but within the range of values measured for the nine commercial varieties.

Data on levels of protein, fat, ash, moisture, carbohydrates, ADF, and NDF, obtained from forage samples did not reveal any significant differences between MON 863 and the non-transgenic parental control, and all values fell within the range measured for the nine commercial varieties

Toxicity

Cry3Bb1 protein extracted and purified from a heterologous E. coli fermentation system was used as the test material for an acute oral toxicity study with mice. The identical cry3Bb1 coding sequence used in the transformation of event MON 863 was used in the transformation of E. coli. The protein expressed by E. coli was assessed and found to be physicochemically and functionally equivalent to that expressed in plant tissue. The bacteria expression platform was used since a sufficient amount of the protein could not be purified from plant tissue. In the acute gavage study, the No Observed Adverse Effect Level (NOAEL) was found to exceed 3200 mg/kg the maximum dose achievable. At that level, no mortality or grossly observable adverse effects were noted.

The NOAEL was considered to be four orders of magnitude (5.8 X 104) times greater than the expected human intake of Cry3Bb1 protein from MON 863 maize. The NOAEL was 1000 times greater than the expected livestock dietary intake of Cry3Bb1 protein from MON 863 maize.

The sequence of amino acids making Cry3Bb1 protein was compared to that of known toxins. There was no sequence homology noted with toxins. As well, there were no structural similarities noted between Cry3Bb1 and known toxins.
These factors indicated that Cry3Bb1 had a low probability to exhibit toxicity to humans or livestock consuming MON 863 maize or products derived from it.

Allergenicity

Current scientific knowledge indicates that many food allergens tend to be abundant proteins within the food product, resistant to proteolytic digestion and heat inactivation and are often glycosylated. The Cry3b1 protein was assessed for allergenicity by examining its digestibility; amino acid sequence homology to known allergens; its glycosylation profile; and history of safe use of microbial sprays.

The results of an in vitro digestive fate study using simulated gastric fluid (SGF) indicated that Cry3Bb1 protein degraded to nondetectable levels in 15 seconds. The protein is also quickly deactivated upon exposure to heat. The protein was compared to known allergens and did not exhibit amino acid sequence homology. The Cry3Bb1 protein is not glycosylated. As well, the protein is present only at very low levels in edible portions of maize.

The long history of use of Bt toxins in microbial sprays has produced numerous safety studies which have demonstrated its low mammalian toxicity. As well, there have been no confirmed cases of allergic reactions to Cry proteins in scientific literature.

From these collective data it was judged that Cry3Bb1 protein in MON 863 maize was unlikely to be a human allergen.

Abstract Collapse

Maize is used as 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. In the United States and Canada, only a small proportion of the whole kernel is consumed by humans, while refined maize products, sweeteners, starch, and oil are abundant in processed foods such as breakfast cereals, dairy goods, and chewing gum.

In the United States and Canada, maize is typically used as animal feed with roughly 70% of the crop fed to livestock, although an increasing proportion is now being used for the production of ethanol. The entire maize plant, 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 maize acreage, and is a major ruminant feedstuff. Livestock that feed on maize include cattle, pigs, poultry, sheep and goats, fish and companion animals.

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

Diabrotica virgifera, western corn root worm (Family Coleoptera), is a major pest of maize in the US maize-growing belt. The larvae feed on maize roots, the damage from which causes nutrient and water depletion and ultimately lodging, making harvesting difficult. In the year 2000, over 14 million acres of United States maize was treated with chemical insecticides for this major pest. The corn root worm is estimated to cost the maize industry in the United States one billion dollars per year due to pesticide costs and crop damage.

Maize line MON 863 was produced using recombinant-DNA techniques to express the cry3Bb1 gene encoding a Coleopteran-specific insecticidal protein from Bacillus thuringiensis (subsp. kumamotoensis) in order to control infestation with corn root worm. This gene was introduced into the publicly available inbred line, A634, by particle acceleration (biolistic) transformation.

The cry3Bb1 gene encodes 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 Coleopteran species, including corn root worm, 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.

MON 863 was tested in field trials in the United States. Data collected from these trials indicated that MON 863 was not different from other maize varieties in terms of agronomic characteristics, aside from resistance to corn root worm

Maize does not have any closely related species growing in the wild in continental United States and Canada. Cultivated maize can naturally cross with annual teosinte (Zea mays ssp. mexicana) when grown in close proximity, however, these wild maize relatives are native to Central America and are not naturalized in Canada or the United States. Additionally, reproductive characteristics such as pollen production, viability, and dispersal were unchanged in MON 863. Gene exchange between MON 863 and maize relatives was determined to be negligible in managed ecosystems, with no potential for transfer to wild species in Canada and the United States.

MON 863 lines expressing the Cry3Bb1 protein were compared to their non-transformed counterpart for relative abundance of beneficial arthropods. Field studies demonstrated that Cry3Bb1 had neither a direct nor an indirect effect on the beneficial arthropod populations. In summary, it was determined that when compared with currently commercialized maize varieties, MON 863 maize did not present an increased risk to or impact on interacting organisms, including humans, with the exception of specific coleopteran insect species.

The authorization for environmental release and livestock feed approval in Canada was granted for 1 year only. Renewal of the authorization was contingent on the submission of a new beneficial insect study as the original study on green lacewings was not considered of an optimal design. The new information was submitted in 2004 and the authorization renewed.

Regulatory authorities in Canada and United States have mandatory requirements for developers of Bt maize to implement specific Insect Resistant Management (IRM) Programs. As for other Bt maize varieties, farmers growing MON 863 are required to plant 20% of their acreage to non-Bt varieties.

Nutritional and anti-nutritional factors in MON 863 were examined and found to be within the normal range of unmodified maize varieties, though there were some differences from the parental line. The Cry3Bb1 protein was found in oral gavage studies to have a No Observed Adverse Effect Level (NOAEL) over 3200 mg/kg which exceeds the expected dietary exposure for humans by approximately 58000X. This level exceeded the livestock dietary exposure by 1000X.

Cry3Bb1 did not exhibit amino acid sequence homology or protein structure homology to known toxins or allergens. In addition, it was found that the Cry3Bb1 protein expressed by MON 863 maize lines digests rapidly in simulated gastric environments, was easily inactivated by heat and was not glycosylated. All these indicated that the Cry3Bb1 protein did not have potential for being an allergen or toxin.

Links to Further Information Expand

Canadian Food Inspection Agency, Plant Biosafety Office European Commission European Commission: Community Register of GM Food and Feed European Food Safety Authority Food Standards Australia New Zealand Japanese Biosafety Clearing House, Ministry of Environment Monsanto Company Office of Food Biotechnology, Health Canada Philippines Department of Agriculture, Bureau of Plant Industry U.S. Department of Agriculture, Animal and Plant Health Inspection Service U.S. Environmental Protection Agency, Office of Pesticide Programs US Food and Drug Administration

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