GM Crop Database

BT11 X GA21 10 (OECD identifier: SYN-BTØ11-1 x MON-ØØØ21-9) maize is an F1 hybrid resulting from the hybridization of the lepidoteran-resistant and herbicide-tolerant maize line BT11 (SYN-BTØ11-1) and the herbicide-tolerant maize line GA21 (MON-ØØØ21-9). 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.

The stacked hybrid BT11 X GA21 expresses three novel proteins: the delta-endotoxin Cry1Ab which confers resistance to the European Corn Borer and other lepidopterans, the PAT protein which confers tolerance to the herbicide glufosinate ammonium, and a modified EPSPS protein which confers tolerance to the herbicide glyphosate. The modified EPSPS protein is produced by the mepsps gene from GA21, the insecticidal protein Cry1Ab is produced by the cry1Ab gene and PAT is produced by the pat gene, both from BT11. 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 BT11 and GA21.

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 Cry1Ab protein is not an enzyme and therefore does not affect plant metabolism. PAT has a high affinity for L-Phosphinothricin, the active ingredient in glufosinate ammonium. The modified EPSPS has high affinity for its substrates phosphoenolpyruvate (PEP) and shikimate-3-phosphate, which are part of the shikimate metabolic pathway. PAT, EPSPS and Cry1Ab are therefore not expected to interact within, nor affect the metabolism of the stacked hybrid.