AnUstilago maydisMutant Partially Blocked in P45014DMActivity Is Hypersensitive to Azole Fungicides

Abstract

AnUstilago maydisergosterol biosynthesis mutant (A14) which is partially blocked in sterol 14α-demethylase (P45014DM) activity is described. This mutant accumulated the abnormal 14α-methyl sterols, eburicol, 14α-methylfecosterol, and obtusifoliol, along with significant amounts of ergosterol. Although the A14 mutant grew nearly as well as the wild type, it was impaired in cell extension growth, which indicated a dysfunction in apical cell wall synthesis. The mutant was also found to be hypersensitive to the azole fungicides penconazole and tebuconazole.