DIFFERENTIAL RESPONSE TO ISOXABEN OF CELLULOSE BIOSYNTHESIS BY WILD-TYPE AND RESISTANT STRAINS OF ARABIDOPSIS-THALIANA

Isoxaben-resistant mutants of Arabidopsis thaliana did not exhibit differences in their uptake, accumulation, or metabolism of isoxaben when compared to the sensitive parent wild-type strain. We have previously shown that isoxaben inhibits incorporation of glucose into an acid-insoluble cell wall fraction thought to be cellulose. Careful cell wall fractionation of the wild-type strain indicates that this is the only component whose biosynthesis is inhibited by isoxaben. The inhibition of this component is relieved in the resistant strains. These mutants are defined by two independent genes. Since neither is involved in the metabolic fate of isoxaben, both should directly affect the binding of isoxaben. This strongly implicates the existence of a multimeric complex as the binding site of isoxaben. © 1991.