GM Crop Database

Database Product Description

TC1507 x DAS-59122-7 (DAS-Ø15Ø7-1 x DAS-59122-7)

Host Organism: Zea mays (Maize)

Trade Name: Herculex® XTRA

Trait: Herbicide tolerant, glufosinate ammonium; Insect resistant, Coleoptera; Insect resistant, Lepidoptera.

Trait Introduction: Traditional plant breeding and selection

Proposed Use: Production for human consumption and livestock feed.

Product Developer: DOW AgroSciences LLC and Pioneer Hi-Bred International Inc.

Summary of Regulatory Approvals

Country	Food	Feed	Environment	Notes
Brazil	2013	2013	2013
Canada		2006	2006
European Union	2010	2010		View Expires 2020
Japan	2005	2006	2006
Korea	2006	2008
Mexico	2006	2006
Philippines	2007	2007
South Africa	2011	2011
Taiwan	2009
Turkey		2012
United States			2005

Introduction Expand

This stacked maize hybrid is a product of traditional plant breeding, and is therefore not automatically subject to regulation in all countries, unlike transgenic plants resulting from recombinant-DNA technologies. The approvals table above does not include entries from these countries. Other countries may request notification in advance of the release of a stacked hybrid, or may request information to conduct an environmental and food safety assessment, and these countries’ decisions are reflected in the approvals table.

The stacked hybrid TC1507 X DAS-59122-7 expresses four novel proteins: the delta-endotoxin Cry1F which confers resistance to the European Corn Borer and other lepidopterans, Cry34Ab1 and Cry35Ab1, which are also delta-endotoxins in this case insecticidal to coleopterans such as the Corn Rootworm, and the PAT protein which confers tolerance to the herbicide glufosinate ammonium. The Cry1F protein is produced by the cry1F gene and PAT is produced by the pat gene, both from TC1507. The Cry34Ab1 and Cry35Ab1 insecticidal proteins are produced by the cry34Ab1 and cry35Ab1 genes from DAS-59122-7, which also contains a copy of the pat gene. The novel traits of each parental line have been combined, through traditional plant breeding, to produce this new hybrid. For a full description of each parental line please refer to the individual product descriptions in the crop database for TC1507 and DAS-59122-7.

The inserted genes and their gene products have a history of safe use, and have undergone review and approval by several regulatory agencies. No interactions among the gene products or negative synergistic effects are expected in the stacked hybrid. The Cry1F, Cry34Ab1 and Cry35Ab1 proteins are not enzymes and therefore do not affect plant metabolism. The PAT enzyme has a high substrate affinity for L-Phosphinothricin, the active ingredient in glufosinate ammonium. These proteins are not expected to interact within, nor affect the metabolism of the stacked hybrid.

Summary of Introduced Genetic Elements Expand

Code	Name	Type	Promoter, other	Terminator	Copies	Form
cry1Fa2	cry1F delta-endotoxin	IR	ubiquitin (ubi) ZM (Zea mays) promoter and the first exon and intron	3' polyadenylation signal from ORF25 (Agrobacterium tumefaciens)	1 functional; 1-2 partial;	Altered coding sequence for optimal expression in plant cells.
pat	phosphinothricin N-acetyltransferase	HT	CaMV 35S	CaMV 35S 3' polyadenylation signal	1 functional;
cry34Ab1	Cry34Ab1 delta-endotoxin	IR	Zea mays ubiquitin gene promoter, intron and 5' UTR	Solanum tuberosum proteinase inhibitor II (PINII)	1 functional	Altered coding sequence for optimal expression in maize
cry35Ab1	Cry35Ab1 delta-endotoxin	IR	Triticum aestivum peroxidase gene root-preferred promoter	Solanum tuberosum proteinase inhibitor II (PINII)	1 functional	Altered coding sequence for optimal expression in maize
pat	phosphinothricin N-acetyltransferase	SM	Cauliflower Mosaic Virus (CaMV) 35S	Cauliflower Mosaic Virus (CaMV) 35S	1 functional

Characteristics of Zea mays (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 var. aizawai	cry1F	While target insects are susceptible to oral doses of Bt proteins, no evidence of toxic effects in laboratory mammals or birds.
Streptomyces viridochromogenes	pat	S. viridochromogenes is ubiquitous in the soil. It exhibits very slight antimicrobial activity, is inhibited by streptomycin, and there have been no reports of adverse affects on humans, animals, or plants.
Bacillus thuringiensis strain PS149B1	cry34Ab1	While target insects are susceptible to oral doses of Bt proteins, there is no evidence of toxic effects in laboratory mammals, in birds or in non-target arthropods.
Bacillus thuringiensis strain PS149B1	cry34Ab1	While target insects are susceptible to oral doses of Bt proteins, there is no evidence of toxic effects in laboratory mammals, in birds or in non-target arthropods.
Streptomyces viridochromogenes	pat	S. viridochromogenes is ubiquitous in the soil. It exhibits very slight antimicrobial activity, is inhibited by streptomycin, and there have been no reports of adverse affects on humans, animals, or plants.

Modification Method Expand: Coming soon.

Characteristics of the Modification Expand: Coming soon.

Environmental Safety Considerations Expand: Coming soon.

Food and/or Feed Safety Considerations Expand: Coming soon.

Abstract Collapse

TC1507 X DAS-59122-7(OECD identifier: DAS-Ø15Ø7-1 X DAS-59122-7) maize is an F1 hybrid resulting from the hybridization of the lepidopteran-resistant inbred maize TC1507 with the coleopteran-resistant maize inbred DAS-59122-7 and marketed as Herculex® XTRA. This stacked maize hybrid is a product of traditional plant breeding, and therefore is not automatically subject to regulation in all jurisdictions as are transgenic plants resulting from recombinant DNA technologies. Certain jurisdictions may request notification in advance of the release of a stacked hybrid, or may request information to conduct an environmental and food safety assessment. Examples of jurisdictions that require either notification or information about stacked hybrids prior to their release into the environment, and for use in human food and livestock feed are Japan and Korea.

Links to Further Information Expand

Brazil Ministry of Science and Technology – MCT, National Biosafety Technical Commission – CTNBio

Technical Opinion no. 3674/2013 on modified corn event TC1507 x DAS-59122-7

Canadian Food Inspection Agency

DD2005-55: Determination of the Safety of Dow AgroSciences Canada Inc. and Pioneer Hi-Bred Production Inc.'s Insect Resistant and Glufosinate-Ammonium Herbicide Tolerant Corn (Zea mays L.) Line 59122

European Food Safety Authority

Scientific Opinion: Application (Reference EFSA-GMO-NL-2005-15) for the placing on the market of the insect-resistant and herbicide-tolerant genetically modified maize 1507 x 59122, for food and feed uses, import and processing under Regulation (EC) No 1829/2003 from Mycogen Seeds, c/o Dow AgroSciences LLC and Pioneer Hi-Bred International, Inc. as represented by Pioneer Overseas Corporation.
[PDF Size: 252.94K bytes]

European Food Safety Authority (EFSA)

COMMISSION DECISION of 28 July 2010 authorising the placing on the market of products containing, consisting of, or produced from genetically modified maize 1507x59122 (DAS-Ø15Ø7-1xDAS-59122-7) pursuant to Regulation (EC) No 1829/2003 of the European Parliament and of the Council

Japanese Biosafety Clearing House, Ministry of Environment

Outline of the biological diversity risk assessment report: Type 1 use approval for TC1507 x DAS-59122-7
[PDF Size: 138.18K bytes]

Mexican Health Secretary Federal Commission for the Protection against Sanitary Risk

Summary Assessment of Safety GMOS DAS-01507-1 x DAS-59122-7

Philippines Department of Agriculture, Bureau of Plant Industry

Determination of the Safety of Pioneer’s and Dow Agro Sciences’ Combined trait product corn: 1507 x 59122 for Direct use as Food, Feed, and Processing
[PDF Size: 33.91K bytes]

Turkish Ministry of Food, Agriculture and Livestock, General Directorate of Agricultural Research and Policies

U S ENVIRONMENTAL PROTECTION AGENCY

BIOPESTICIDES REGISTRATION ACTION DOCUMENT Optimum® AcreMax™ B.t. Corn Seed Blends (Event DAS-Ø15Ø7-1 x DAS-59122-7)

This record was last modified on Tuesday, November 3, 2015

Product Related Info

Biology Documents

Maize biology document
Biology of Maize L.
General Description

Maize is a tall, monoecious, annual grass varying in height from 1 to 4 meters (Watson & Dallwitz 1992). The main stem is made up of clearly defined nodes and internodes. Internodes are wide at the base and gradually taper to the terminal inflorescence at the top of the plant. Leaf blades are found in an alternating pattern along the stem. Maize is a unique grass as both male and female flowers are borne on the same plant but are located separately. The tassels or staminate (male) inflorescence form large spreading terminal panicles that resemble spike-like racemes. Pollen is shed from the tassel and is viable for approximately 10 to 30 minutes as it is rapidly desiccated in the air (Kiesselbach 1980). Maize plants shed pollen for up to 14 days. The reproductive phase begins when one or two auxiliary buds, present in the leaf axils, develop and form the pistillate inflorescence or female flower (Purseglove 1972). The auxiliary bud starts the transformation to form a long ‘cob’ on which the flowers will be borne. From each flower a style begins to elongate towards the tip of the cob in preparation for fertilization. These styles form long threads, known as silks. The base of the silk is unique, as it elongates continuously until fertilization occurs (Purseglove 1972). Styles may reach a length of 30 cm, the longest known in the plant kingdom. Individual maize kernels, or fruit, are unique in that mature seed is not covered by floral bracts (glumes, lemmas, and paleas) as in most other grasses, but rather the entire structure is enclosed and protected by large modified leaf bracts, collectively referred to as the ear (Hitchcock and Chase 1951). The mature female flowers will remain ready for fertilization for up to two weeks, at which point if fertilization has not occurred, the nucleus will de-organize and fertilization will no longer be possible (Hitchcock & Chase 1951). The pollen of maize, a protandrous plant, matures before the female flower is receptive (Purseglove 1972). This may have been an ancient mechanism to ensure cross-pollination, but is no longer considered conducive to modern agricultural practices. However, decades of conventional selection and improvement have produced many maize varieties with similar maturities for both male and female flowers, to ensure seed set for agricultural proposes.

Reproduction

Under natural conditions, maize reproduces only by seed production. Pollination occurs with the transfer of pollen from the tassels to the silks of the ear. About 95% of the ovules are cross-pollinated and about 5% are self-pollinated (Poehlman 1959), although plants are completely self-compatible. Maize, as a thoroughly domesticated plant, has lost all ability to disseminate its seeds and relies entirely on the aid of man for its distribution (Stoskopf 1985). The kernels are tightly held on the cobs and if ears fall to the ground, so many competing seedlings emerge that the likelihood that any will grow to maturity is extremely low. Maize cannot reproduce asexually by natural means. It is possible to reproduce maize using tissue culture techniques, however, it has proven extremely difficult with a low rate of success (Hoisington et al. 1998).

Classification and Phylogeny of Maize

Zea is a genus belonging to the grass family, Poaceae, in the Andropogoneae tribe, but is commonly cited in literature to belong to the tribe Maydeae. Zea (zeia) was derived from an old Greek name for a food grass. The genus Zea consists of four species of which only Zea mays ssp. mays L. is economically important. The other Zea species, referred to as teosintes, are largely wild grasses native to Mexico and Central America (Doebley 1990). The number of chromosomes in Zea mays is 2n=20, 21, 22, 24 (FAO 2000c). The tribe Maydeae consists of seven genera: two of American origin, Zea and Tripsacum; and five of Eastern origin which extend from India through Southeastern Asia to Australia and include Coix, Sclerachne, Polytoca, Chionachne and Trilobachne (Watson & Dallwitz 1992). It is generally agreed that maize phylogeny was largely determined by the American genera Zea and Tripsacum, however it is accepted that the genus Coix contributed to the phylogenetic development of the species Z. mays (Radu et al. 1997). The genus Manisuris, from the tribe Andropogoneae, may also have contributed to the evolution of Zea mays (Eubanks 1997a; Radu et al. 1997).

Center of Origin and Progenitors of Maize

The center of origin for Zea mays ssp. mays has been established as the Mesoamerican region, now Mexico and Central America (Watson & Dallwitz 1992). The exact period of domestication and the ancestors from which maize arose are unclear. Archaeological records suggest that domestication of maize began at least 6000 years ago, occurring independently in regions of the southwestern United States, Mexico, and Central America (Mangelsdorf 1974). The origins of domesticated maize have been difficult to trace as hybridization events in its evolution are thought to have involved a now extinct wild maize ancestor of which little evidence has been found (Eubanks 1997a).

Germplasm Diversity

A study in 1992 concluded that maize landraces occupied 42% of the land under production in less developed countries (México 1994). Mexico and Central America are the only regions where ancient maize lines, such as pod corn, are found (Mink & Dorosh 1985). The survival of maize landraces has been attributed to the integral role maize sustains in small communities where it has very specific uses for food and other special functions. These landraces have been well characterized in Latin America, and germplasm not yet evaluated is known to be present in the region. There is a growing trend in developing countries to adopt improved maize varieties, primarily to meet market demand. In Mexico, only 20% of the corn varieties grown 50 years ago remain in cultivation (World Watch Institute 2000). The narrowing of genetic diversity in modern maize varieties emphasizes the importance of conserving genetic traits for future plant breeding. Leading the way in preserving maize germplasm is CIMMYT (International Maize and Wheat Improvement Centre), which has the world’s largest collection of maize accessions, with over 17,000 lines (CIMMYT 2000). Collections of distant maize relatives native to Asia have been recommended by conservation experts to ensure their preservation for future research (Sharma 1998).

Relatives of Maize

The closest wild relatives of maize are the teosintes which all belong to the genus Zea. The teosintes are wild grasses native to Mexico and Central America and have limited distribution (Mangelsdorf et al. 1981). Teosinte species show little tendency to spread beyond their natural range and distribution is restricted to North, Central and South America (Watson & Dallwitz 1992). The nearest teosinte relative to Z. mays ssp. mays is Z. mays ssp. mexicana (Schrader) Iltis (previously classified as Euchlaena mexicana, Zea mexicana) (2n = 20). This Central Mexican annual teosinte is a large flowered, mostly weedy grass with a broad distribution across the central highlands of Mexico. It does not spread readily. It has limited use as a forage and green fodder crop, but can be problematic due to weedy tendencies (Doebley 1990, Watson & Dallwitz 1992). The closest wild relatives to maize outside the Zea genus are from the genus Tripsacum. The genus Tripsacum is comprised of about 12 species that are mostly native to Mexico and Guatemala but are widely distributed throughout warm regions in the USA and South America, with some species present in Asia and Southeast Asia (Watson & Dallwitz 1992). All species are perennial, warm season grasses.

Outcrossing

Gene flow from maize can occur by two means: pollen transfer and seed dispersal. Seed dispersal can be readily controlled in maize as domestication has all but eliminated any seed dispersal mechanisms that ancestral maize may have previously used (Purseglove 1972). The kernels are held tightly on the cobs and if the ear falls to the ground, competing seedlings limit growth to maturity (Gould 1968). Pollen movement is the only effective means of gene escape from maize plants. Pollen is released from the tassels at the top of the plant and transported by wind to the female flowers located on the stalk. Pollen shed occurs over a 14 day period, with a peak during the first 5 days of shed (Sears 2000). The stigmas are receptive for a large part of this two week interval (Kiesselbach 1980). Insects, such as bees, have been observed to collect pollen from maize tassels, but they do not play a significant role in cross-pollination as there is no incentive to visit the female flowers (Rayor et al. 1972).

Wind speed and direction affect pollen distribution

Differences in flowering dates among commercial maize varieties are small. Cross-pollination between varieties may occur if grown in adjacent fields. The limited viability of maize pollen reduces the risk of cross-pollination, as a receptive host must be found within the 30 minutes that the pollen remains biologically active. Cross-pollination is also affected by the concentration of maize pollen released; pollen produced by a maize crop will successfully compete with foreign pollen sources when present in higher concentrations (Rayor et al. 1972). The isolation of crops using separation distances and physical barriers are common techniques for restricting gene flow and ensuring seed purity for maize seed production. Cross-pollination is controlled in seed lots by separating different lines. The OECD standards require a minimum 200 m (660 ft) isolation distance for maize seed production. This distance has been estimated to maintain inbred lines at 99.9% purity. Physical barriers, such as trees or barrier rows, are also effective in reducing cross-pollination. Detasseling or bagging the tassel effectively prevents pollen movement and limits gene flow.

Intraspecific hybidization

All forms of Zea mays spp mays, such as dent, sweet, and pop corn, freely cross pollinate forming fertile hybrids (Pursglove 1972).

Interspecific hybridization

All teosintes can be crossed to maize and form fertile hybrids, except for the tetraploid Z. perennis. Maize-teosinte hybrids exhibit low fitness and have little impact on gene introgression in subsequent generations (Galinat 1988). The tendency to form natural hybrids differs among teosintes: Z. luxurians rarely hybridizes with maize, whereas Z. mays ssp. mexicana frequently forms hybrids (Wilkes 1977). Molecular data confirms that there is gene flow between maize and teosinte and suggests that introgression of maize and teosinte occurs in both directions but at low levels (Doebley 1990).

Intergeneric hybridization Tripsacum species (T. dactyloides, T. floridanum, T. lanceolatum, and T. pilosum) have been successfully hand crossed with maize to form hybrids. The hybrids generally have 28 chromosomes, 10 from maize and 18 from Tripsacum, and are pollen sterile with limited female fertility (Mangelsdorf & Reeves 1939, Mangelsdorf 1974). This infertility is common in such wide crosses because of differences in chromosome number and lack of pairing between chromosomes (Eubanks 1997b). Maize readily crosses with hexaploid wheat (Triticum aestivum) with high frequencies of fertilization and embryo formation (plant breeders use maize pollen to develop double haploids of hexaploid wheat). However, maize chromosomes are eliminated from the genome during the initial stages of meiosis and result in haploid embryos. There is little evidence to suggest fertile hybrids between maize and hexaploid wheat could be produced in nature. There have been unsubstantiated reports of hybridization between maize and sugar cane (Saccaharum sp.).

Biology References
1. CIMMYT (International Maize and Wheat Improvement Centre) (2000). CGIAR Research, Areas of Research: Maize (Zea mays L.) http://www.cgiar.org/areas/maize.htm
2. Doebley, J. F. (1990). Molecular Evidence for Gene Flow among Zea species. BioScience 40, 443- 448.
3. Eubanks, M.W. (1997a). Further evidence for two progenitors in the origin of maize. Maize Newsletter 71, 35-35.
4. FAO (2000c). Species Description. Zea mays L. http://www.fao.org/WAICENT/faoinfo/agricult/agp/agpc/doc/gbase/data/pf000342.htm
5. Galinat, W.C. (1988). The origin of corn. In: Corn and Corn Improvement. Agronomy Monographs No.18. American Society of Agronomy, G.F Sprague and J.W. Dudley, (eds.). Madison, Wisconsin, pp. 1-31.
6. Gould, F.W. (1968). Grass Systematics. McGraw Hill, N.Y., USA.
7. Hitchcock, A.S. & A. Chase. (1951). Manual of the Grasses of the United States (Volume 2). Dover Publications: N.Y. p. 790-796.
8. Hoisington, D., Listman, G.M. & Morris, M.L. (1998). Varietal development: applied biotechnology. In: Maize Seed Industries in Developing Countries. M. L. Morris (ed). Lynne Rienner Publishers, Inc. pp. 77-102.
9. Kiesselbach, T.A. (1980). The structure and reproduction of corn. Reprint of: Research Bulletin No. 161. 1949. Agricultural Experiment Station, Lincoln, Nebraska. University of Nebraska Press. p. 93.
10. Laurie, D.A. & Bennett, M.D. (1986). Wheat x maize hybridization. Can. J. Genet. Cytol. 28, 313-316.
11. Mangelsdorf, P. C. & Reeves, R.G. (1939). The origin of Indian corn and its relatives. Texas Agric. Expt. Sta. Bull. 574.
12. Mangelsdorf, P. C. (1974). Corn: its Origin, Evolution and Improvement. Harvard Univ. Press, Cambridge, Mass.
13. Mangelsdorf, P. C., Roberts, L.M. & Rogers, J.S. (1981). The probable origin of annual teosintes. Bussey Inst., Harvard Univ. Publ. 10, 1- 69.
14. México, D.F. (1994). Maize seed industries revisited: emerging roles of the public and private sectors. World Maize Facts and Trends1993/94. CIMMYT.
15. Mink, S. D. & Dorosh, P.A. (1987). An overview of corn production. In: The Corn Economy of Indonesia. Cornell University Press, London.
16. Poehlman, J.M. (1959). Breeding Field Crops. Holt, New York, USA.
17. Purseglove, J.W. (1972). Tropical Crops: Monocotyledons 1. Longman Group Limited., London.
18. Radu, A, Urechean, V., Naidin, C. & Motorga, V. (1997). The theoretical significance of a mutant in the phylogeny of the species Zea mays L. Maize Newsletter 71, 77-78.
19. Rayor, G.S., Ogden, E.C. & Hayes, J.V. (1972). Dispersion and deposition of corn pollen from experimental sources. Agronomy Journal 64, 420-427.
20. Sears, M.K., Stanley-Horn, D.E. & Matilla, H.R. (2000). Ecological impact of Bt corn pollen on Monarch butterfly in Ontario. Canadian Food Inspection Agency (http://www.cfia-acia.agr.ca/english/ plaveg/pbo/btmone.shtml)
21. Sharma, A.B. (1998). Experts for conservation of wild crop varieties. The Financial Express. Indian Express Group.
22. Stoskopf, N.C. (1985). Cereal Grain Crops. Reston, Virginia: Reston Publishing Company, Inc., Prentice-Hall Company.
23. Watson, L. & Dallwitz, M.J. (1992). Grass Genera of the World: Descriptions, Illustrations, Identification, and Information Retrieval; including Synonyms, Morphology, Anatomy, Physiology, Phytochemistry, Cytology, Classification, Pathogens, World and Local Distribution, and References. Version:18th August 1999. http://biodiversity.uno.edu/delta
24. World Watch Institute (2000). Crop gene diversity declining. Trends in Plant Science 5, 7.
25. Wilkes, H.G. (1977). Hybridization of maize and teosinte, in Mexico and Guatemala and the improvement of maize. Economic Botany 31, 254-293.
LAST UPDATED: SEPTEMBER 2002

Documents

Key food and feed nutrients and antinutrients of maize

Query Options: New Database Query

Go to Event

GM Crop Database

Database Product Description

Summary of Regulatory Approvals

Introduction Expand

Summary of Introduced Genetic Elements Expand

Characteristics of Zea mays (Maize) Expand

Donor Organism Characteristics Expand

Modification Method Expand

Characteristics of the Modification Expand

Environmental Safety Considerations Expand

Food and/or Feed Safety Considerations Expand

Abstract Collapse

Links to Further Information Expand

Output Options

Synopsis

Product Related Info

Query Options

Help

GM Crop Database

Database Product Description

Summary of Regulatory Approvals

Introduction Expand

Summary of Introduced Genetic Elements Expand

Characteristics of Zea mays (Maize) Expand

Donor Organism Characteristics Expand

Modification Method Expand

Characteristics of the Modification Expand

Environmental Safety Considerations Expand

Food and/or Feed Safety Considerations Expand

Abstract Collapse

Links to Further Information Expand

Output Options

Synopsis

Product Related Info

Biology Documents

Biology of Maize L.

Documents

Query Options

Help