Sterols and Fatty Acids in the Plasma Membranes of Taphrina Deformans Cultured at Low Temperature and with Propiconazole
Propiconazole is a triazole that blocks the C-14 demethylation of lanosterol, preventing its conversion to ergosterol or functionally equivalent sterols (Weete, 1987). Taphrina deformans, a foliar pathogen of peach that proliferates by budding in laboratory culture, is highly sensitive to this inhibitor in that only 0.073 μg/ml are required for 50% suppression of growth (Sancholle et al., 1984). Brassicasterol, as the principal sterol of this fungus (Weete et al., 1983; 1985a), is decreased in favor of 24-methylene-24, 25-dihydrolanosterol and obtusifoliol in the presence of sublethal doses of this inhibitor (Weete et al., 1983), a response that also occurs in the plasma membrane (Weete et al., 1985b). Alterations in phospholipid-fatty acids also accompany the changes in sterol content, i.e. increase in unsaturation due to decreased oleic acid and increased linoleic and linolenic acids (Weete et al., 1983; 1985b). Since T. deformans infects peach leaves prior to bud break when the temperature is relatively cold, we conducted the study reported here for the purpose of assessing whether the sensitivity of this fungus differs at the infection temperature (8–13°C) compared to that of the laboratory cultivation temperature (18°C), and whether the above changes in plasma membrane composition occur.
KeywordsSucrose Magnesium Acetone EDTA Diene
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