<p style="text-align: justify;">Soybean lines A2704-12, A2704-21, and A5547-35 were developed through a specific genetic modification to allow for the use of glufosinate ammonium, the active ingredient in phosphinothricin herbicides (Basta&reg;, Ignite&reg;, Rely&reg;, Liberty&reg;, Harvest&reg;, and Finale&reg;) as a weed control option in soybean crops. The <i>pat</i> gene, conferring tolerance to glufosinate ammonium, was cloned from the common aerobic soil actinomycete, <i>Streptomyces viridochromogenes</i>, and encodes the enzyme phosphinothricin-N-acetyltransferase (PAT).</p>

<p style="text-align: justify;">Glufosinate is a short name for the ammonium salt, glufosinate-ammonium. It is a broad-spectrum contact herbicide and is used to control a wide range of weeds after the crop emerges or for total vegetation control on land not used for cultivation. Glufosinate is a natural compound isolated from two species of Streptomyces fungi. It inhibits the activity of an enzyme, glutamine synthetase, which is necessary for the production of glutamine and for ammonia detoxification. The application of glufosinate leads to reduced glutamine and increased ammonia levels in the plant tissues. This causes photosynthesis to stop and the plant dies within a few days. Glufosinate also inhibits the same enzyme in animals. It is highly biodegradable, has no residual activity, and very low toxicity for humans and wild fauna. The PAT enzyme detoxifies phosphinothricin via acetylation into an inactive compound.</p>
