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Effect of mutagenesis at serine 653 of Arabidopsis thaliana acetohydroxyacid synthase on the sensitivity to imidazolinone and sulfonylurea herbicides
Author(s) -
Lee Yu-Ting,
Chang Alan K,
Duggleby Ronald G
Publication year - 1999
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(99)00668-7
Subject(s) - sulfonylurea , serine , threonine , asparagine , alanine , enzyme , arabidopsis thaliana , biochemistry , chemistry , mutant , mutagenesis , phenylalanine , wild type , microbiology and biotechnology , biology , amino acid , gene , endocrinology , insulin
Resistance to sulfonylurea and imidazolinone herbicides can occur by mutations in acetohydroxyacid synthase (EC 4.1.3.18). Changing serine 653 to asparagine is known to cause insensitivity to imidazolinones but not to sulfonylureas. Here, S‐653 of the Arabidopsis thaliana enzyme was mutated to alanine, threonine and phenylalanine. The purified mutated enzymes resemble wild‐type in their enzymatic properties. The threonine and phenylalanine mutants are imidazolinone‐resistant and the latter is also slightly sulfonylurea‐resistant. The alanine mutant remains sensitive to both herbicides. The results suggest that the β‐hydroxyl group is not required for imidazolinone binding and that the size of the side‐chain determines resistance.