The BXN™ line of cotton (Gossypium hyrsutum) was developed through a specific genetic modification to be resistant to the activity of oxynil-containing herbicides, such as bromoxynil. The oxynil family of herbicides is active against dicotyledonous plants by blocking electron flow during the light reaction of photosynthesis. The novel variety was developed by insertion of a gene encoding a bacterial enzyme that hydrolyses ioxynil and bromoxynil into non-phytotoxic compounds. The modified cotton line permits farmers to use oxynil-containing herbicides for weed control in the cultivation of cotton.<br>The BXN™ cotton line was created by Agrobacterium-mediated transformation in which the transfer-DNA (T-DNA) contained the gene encoding the enzyme nitrilase from the soil bacterium Klebsiella pneumoniae subsp. ozaenae. In addition, the T-DNA contained sequences encoding the enzyme neomycin phosphotransferase II (NPTII) from the Tn5 transposon of Escherichia coli, strain K12. There was no incorporation of translatable plasmid DNA sequences outside of the T-DNA region.<br>Refined edible cottonseed oil does not contain any detectable protein and consists of purified glycerides. Using a sensitive Western blotting technique that was capable of detecting the enzymes nitrilase and NPTII at levels of 0.1 ppm and 0.01 ppm, respectively, there were no detectable amounts of either of these proteins in refined oil from BXN™ cotton.