Database Product Description
- Host Organism
- Zea mays L. (Maize)
Resistance to lepidopteran pests
- 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
Summary of Introduced Genetic Elements Expand
Characteristics of Zea mays L. (Maize) Expand
Donor Organism Characteristics Expand
Modification Method Expand
Characteristics of the Modification Expand
Food and/or Feed Safety Considerations Expand
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.
In the United States maize is typically used as animal feed, with roughly 70% of the crop fed to livestock, although an increasing share is now being used to produce ethanol for fuel. 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 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.
MON 89034 was developed as a second generation insect-resistant maize product to provide enhanced benefits for the control of lepidopteran insect pests. MON 89034 produces the Cry1A.105 and Cry2Ab2 proteins derived from Bacillus thuringiensis, which are active against lepidopteran insect pests. MON 89034 is intended to serve farmers' needs for controlling a wider spectrum of lepidopteran pests and help assure the durability of insect-resistant maize. MON 89034 provides control of Ostrinia species such as European corn borer (ECB) and Asian corn borer, and Diatraea species such as southwestern corn borer (SWCB) and sugarcane borer. MON 89034 also provides a high level control of fall armyworm (FAW) throughout the season and improved protection from damage caused by corn earworm (CEW). In addition to the wider spectrum of insect control, the combination of the Cry1A.105 and Cry2Ab2 insecticidal proteins in a single plant provides a much more effective insect resistance management (IRM) tool. The results of mathematical modeling indicate that biotechnology-derived plants expressing two Cry proteins will have significantly greater durability than plants producing either of the single proteins if the cross-resistance between the Cry proteins is low and the mortality of susceptible insects caused by each of the individual proteins is at least 90%. Comparative biophysical studies indicate that the Cry1A.105 and Cry2Ab2 proteins have important differences in their mode of action, specifically in the way in which they bind to the lepidopteran midgut. Therefore, the probability of cross-resistance between these two proteins is low. Furthermore, in vitro and in planta studies with Cry1A.105 and Cry2Ab2 demonstrate that both proteins are highly active against the primary lepidopteran pests of corn (ECB, SWCB, CEW, and FAW), particularly ECB, achieving close to or greater than the critical 95% level of control in all cases.
MON 89034 was produced by Agrobacterium-mediated transformation of corn with PVZMIR245, which is a binary vector containing 2 T-DNAs. The first T-DNA, designated as T-DNA I, contained the cry1A.105 and the cry2Ab2 expression cassettes. The second T-DNA, designated as T-DNA II, contained the nptII (neomycin phosphotransferase II) expression cassette. During transformation, both T-DNAs were inserted into the genome. The nptII gene was used as the selectable marker which was needed for selection of the transformed cells. Once the transgenic cells were identified, the selectable marker gene was no longer needed and traditional breeding was used to isolate plants that only contained the cry1A.105 and cry2Ab2 expression cassettes (T-DNA I). Molecular characterization of MON 89034 by Southern blot analyses demonstrated that the DNA inserted into the corn genome is present at a single locus and contains one functional copy of the cry1A.105 and the cry2Ab2 expression cassettes. All genetic elements are present in the inserted DNA as expected with the exception that the e35S promoter, which regulates expression of the cry1A.105 gene, has been modified and that the Right Border sequence present in PV-ZMIR245 was replaced by a Left Border sequence in MON 89034. No backbone plasmid DNA or nptII sequences were detected.
As the selectable marker gene employed in the transformation process was removed during development of the final event, the two insecticidal proteins are the only new proteins expressed in this plant. This was confirmed by a molecular analysis that identified only the genes coding for the insecticidal proteins as being present in the final event, with no evidence for presence of the selecable marker gene. A review of the potential toxicity and allergenicity of these two proteins was made, in addition to a comparison of the composition of the grain and forage from this transgenic event with non-transgenic maize. Agronomic characters were evaluated in field trials, also in comparison to non-transgenic maize. No evidence was found to suggest that this product would pose a greater risk to human or animal health, or to the environment.
The food and livestock feed safety of MON89034 maize grain and forage was established based on several standard criteria. As part of the safety assessment, the nutritional composition of MON89034 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 MON89034 forage harvested at the late dough to early dent stages.
Links to Further Information Expand
This record was last modified on Thursday, February 26, 2015