Inhibition of the acetyl-coa carboxylase of barley chloroplasts by cycloxydim and sethoxydim

Abstract

The effect of the three cyclohexane-1,3-dione derivatives cycloxydim, sethoxydim and clethodim on the incorporation of l4C-labelled acetate, malonate, acetyl-C oA or malonyl-CoA into fatty acids was studied in an enzyme preparation isolated from barley chloroplasts (H ordeum vulgare L. var. “A lexis”). The herbicides cycloxydim, clethodim and sethoxydim block the de novo fatty acid biosynthesis from [2-l4C]acetate and [l-14C]acetyl-CoA, whereas that of [2-14C]malonate and [2-l4C]m alonyl-CoA is not affected. The data indicate that the mode of action the cyclohexane-1,3-dione derivatives in the sensitive plant consists in the inhibition of de novo fatty acid biosynthesis by blocking the acetyl-CoA carboxylase (EC 6.4.1.2.). © 1987, Walter de Gruyter. All rights reserved.