<p style="text-align: justify;">BW7 (Clearfield&trade;) bread wheat was developed to allow the use of imidazolinone herbicides as a weed control option in spring wheat. This trait was developed using chemically induced seed mutagenesis and whole plant selection procedures. This wheat line expresses a mutated form of the acetohydroxyacid synthase (AHAS, sometimes referred to as acetolactate synthase or ALS) enzyme, which renders the plant tolerant to levels of imidazolinone herbicides used in weed control.</p>

<p style="text-align: justify;">AHAS catalyses the first step in the biosynthesis of the branched-chain amino acids isoleucine, leucine, and valine, and is active in the glycolytic pathway of plant metabolism. When conventional plants (<i>i.e.</i>, weeds) are treated with imidazolinone herbicides, the herbicide binds to a specific site on the enzyme, thereby inhibiting its activity. The result of this enzyme inhibition is a decrease in the synthesis of branched-chain amino acids and an accumulation of toxic levels of ?-ketoglutarate, which results in the eventual death of the plant.</p>
