A novel thiazolidinone herbicide is a potent inhibitor of glucose incorporation into cell wall material†

Abstract

5-tert-Butyl-carbamoyloxy-3-(3-trifluoromethyl) phenyl-4-thiazolidinone (compound 1), a representative of a novel class of thiazolidinone herbicides, shows potential for the pre-emergence control of grasses and small-seeded broad-leaved weeds in crops such as soyabean. This compound powerfully inhibited the growth and lateral branching of the roots of agar-grown seedlings of susceptible species but had no apparent effect on the growth of Escherichia coli, Aspergillus nidulans, Fusarium culmorum or of insects cells in liquid culture. It inhibited the growth of plant (Daucus carota and Zea mays) cells in liquid culture and this inhibition was not reversed by addition to the medium of mixtures of either amino acids or of nucleosides. It did not inhibit fatty acid biosynthesis, respiration, the biosynthesis of sterols, or the biosynthesis of protein in the systems examined herein. By contrast, it induced potent (IC50 c.50 nM) and rapid inhibition of the incorporation of [3H]glucose into the acid-insoluble cell-wall fraction of roots. Thus, compound 1 exerts its herbicidal effect, directly or indirectly, through inhibition of the biosynthesis of cellulose and cellulose-like polysaccharides, in a manner similar to isoxaben and dichlobenil. Mutant lines of Arabidopsis thaliana selected for resistance to isoxaben were cross-resistant to compound 1. Consistent with the selective herbicidal activity observed, the compound was a potent inhibitor of [3H]glucose incorporation into the polysaccharide of seedling roots of Zea mays and of Setaria viridis but only relatively weakly active on Glycine max and Ipomoea hederacea. Given that compound 1 appeared to be metabolised only slowly and that [3H]glucose incorporation experiments were conducted within a total period of less than 90 min, it seems probable that, as in the case of the acetyl CoA carboxylase-inhibitor graminicides, the observed selectivity is determined by species-dependent differences at the (in this case unknown) molecular target site for the herbicide. © 1998 Society of Chemical Industry