Abstract
When Monilinia fiructigena was treated with S-1358 at a concentration of 10μM, both quality and quantity of digitonin-precipitable sterols were markedly altered. The amount of ergosterol which is a major sterol in the control culture was reduced by S-1358 and the concomitant accumulation of obtusifoliol (one of 4α-methyl sterols) and 24-methylenedihy-drolanosterol (one of 4, 4-dimethyl sterols) was observed. The time course study of acetate-U-14C incorporation into the digitonin-precipitable sterols revealed that 4α-methyl sterols accumulated slowly in the treated culture, while 4, 4-dimethyl sterols accumulated rapidly. The accumulation of the sterols containing “extra” methyl groups suggests that S-1358 blocks demethylation reactions in the conversion from lanosterol to ergosterol in M. fructigena.
