Roundup Ready™ cotton

Cotton line 1445 was genetically engineered to express resistance to glyphosate, the active ingredient in the herbicide Roundup®, allowing for its use as a weed control option. In order to obtain field tolerance to glyphosate herbicide, a bacterial gene encoding a glyphosate-tolerant form of the enzyme 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) was introduced into the cotton genome by Agrobacterium-mediated transformation.

Variety: Coker 312

PV-GHGT07

Information on the inserted DNA sequences
Molecular characterization demonstrates that one T-DNA insert was integrated into the cotton genome to produce cotton 1445.  The insert contains the CoMV promoter region, a codon optimised cp4epsps coding sequence, nptII, aad (that is not expressed in plants) and a portion of ori-V coding regions.

Vector information
The plasmid vector PV-GHGT07 contains well characterized DNA segments required for selection and replication of the plasmid in the bacteria as well as a right border for initiating the region of T-DNA,  into the plant genomic DNA. The plant expression vectors were assembled, transformed in E. coli and mated into the ABI Agrobacterium strain by the triparental conjugation system using the helper plasmid pRK2013. The binary ABI strain contains the disarmed (lacking the T-DNA phytohormone genes) pTiC58 plasmid pMP90RK in a choramphenicol-resistant derivative of the A. tumefaciens strain A208. The disarmed pMP90RK Ti plasmid does not carry the T-DNA phytohormone genes and is unable to grow the crown gall disease.

Coding sequences of the EPSPS gene was altered for optimal expression in plants.

The EPSPS enzyme is present in all plants, bacteria, and fungi, and is part of an important biochemical pathway called the shikimate pathway, which is involved in the production of aromatic amino acids and other aromatic compounds. When conventional cotton plants are treated with glyphosate, the plants cannot produce the aromatic amino acids needed to grow and survive. EPSPS is not present in mammals, birds or aquatic life forms, which do not synthesize their own aromatic amino acids. For this reason, glyphosate has little toxicity to these organisms. The EPSPS enzyme is naturally present in foods derived from plant and microbial sources.