Inhibition of de novo Fatty-Acid Biosynthesis in Isolated Chloroplasts by Different Antibiotics and Herbicides
Abstract Two natural antibiotics, cerulenin and thiolactomycin, were tested for their inhibitory efficacy on de novo fatty-acid biosynthesis of chloroplasts isolated from oat and spinach seedlings and compared with that of known herbicides. With both antibiotics a strong dose-dependent inhibition of the incorporation of [l-14C]acetate into the fatty-acid fraction of the isolated plastids was detected. The l50-values for the inhibition of acetate incorporation into fatty acids are about 4 µM in the case of thiolactomycin and about 50 µM in the case of cerulenin for both mono-and dicotyledonous plants. These values are much higher than those of the particular graminicides cycloxydim and diclofop (0.15 and 0.1 µM), which were developed to control grass weeds in dicotyledonous crop cultures.