Wirkungsmechanismus des systemischen Fungicids Carboxin

The selective effect of oxathiin compounds (DCMO) on basidiomycetes does not depend on stronger accumulation of the fungicide by sensitive fungi. Uptake of DCMO is closely related to the lipid content of a fungus. It is shown by electron microscopy that within 120 min DCMO damages the mitochondrial system and the vacuolar membrane, while plasmalemma, nuclear membrane and ER remain unchanged. In isolated mitochondria of sensitive fungi DCMO causes a similar inhibition of respiration as in whole cells. Succino-dehydrogenase (SDH) is inhibited to the same extent, while NADH-dehydrogenase is only weakly inhibited and malate-dehydrogenase not at all. Inhibition of SDH is reduced with increasing temperature. Soluble SDH is insensitive to DCMO. The point of attack of DCMO is considered to be SDH in situ or a closely following reaction.