<p style="text-align: justify;">Rice lines IMINTA 1 and IMINTA 4 were developed to be tolerant to imidazolinone herbicides to provide an alternative strategy for weed control in rice. Imidazolinone herbicides are active against the acetolactate synthase (ALS) enzyme in plants, which catalyzes the first reaction in the biosynthesis of branched-chain amino acids. Imidazolinone inhibits the production of these essential amino acids (valine, leucine and isoleucine), resulting in a decrease in protein synthesis and the eventual death of the plant.</p>

<p style="text-align: justify;">The development of these events was acomplished by mutagenesis and the herbicide tolerance results from a single point mutation in the ALS gene (also known as acetohydroxyacid synthase or AHAS), such that the resulting enzyme has a single amino acid substitution and is no longer affected by imidazolinone herbicides. Previously authorized rice events CL121, CL141, CFX51 and PWC16 also contain modified ALS genes conferring tolerance to imidazolinone herbicides.</p>
