Herbicide-tolerant soybean

The soybean line A2704-12 was developed to allow for the use of glufosinate ammonium, the active ingredient in phosphinothricin herbicides (Basta® , Ignite® , Rely® , Liberty® , Harvest® , and Finale®) as a weed control option. These genetically engineered soybean lines contain the fungal enzyme phosphinothricin-N-acetyltransferase (PAT) that allows these plants to survive the otherwise lethal application of glufosinate. The pat gene inserted was isolated from a common soil fungus, Streptomyces viridochromogenes, and introduced into the soybean genome by particle acceleration (biolistic) transformation.

The PAT enzyme converts L-phosphinothricin (PPT), the active ingredient in glufosinate ammonium, to an inactive form thereby conferring resistance to the herbicide. In absence of PAT, application of glufosinate leads to reduced production of the amino acid glutamine and increased ammonia levels in the plant tissues which are lethal to the plant. The PAT enzyme is not known to have any toxic properties.

pB2/35SAcK (AKA: pWRG5143)

The PAT gene from Streptomyces viridochromogenes was synthetically modified with plant preferred codons.

The bacterial ampicillin resistance gene was also integrated into the host genome. It is however only expressed in bacterial cells.

Southern blot analysis indicated that 5 copies of the PAT gene and 2 copies of the ampR gene were integrated into the host genome.