Methods and compositions involving ALS variants with native substrate preference

A method of producing an ALS inhibitor-tolerant soybean plant cell comprising:

• a) transforming a soybean plant cell with a recombinant polynucleotide comprising a nucleotide sequence encoding a soybean acetolactate synthase (ALS) inhibitor-tolerant polypeptide comprising an amino acid sequence that is at least 97.5% identical to SEQ ID NO:
• 1, wherein the amino acid sequence contains a serine at the amino acid residue corresponding to position 178 of SEQ ID NO:
• 1, and wherein said polynucleotide is operably linked to an S-adenosylmethionine synthase promoter;
• b) placing said cell in a medium that promotes growth;
• c) regenerating a transgenic plant from said plant cell;
• and
• d) selecting at least one plant produced from said cell that is tolerant to at least one ALS inhibitor in the imidazolinone class, wherein said plant produces at least one seed with less than 0.5% C17 fatty acids relative to the total amount of fatty acids present in the seed.