Abstract

A gene (ERG11) encoding cytochrome P450 sterol 14α-demethylase (P450_14DM) was isolated from the maize pathogen,Ustilago maydis , by amplifying part of the coding region of the gene using PCR and by employing the amplified DNA fragment as a hybridization probe to recover the complete gene from an U. maydis λEMBL3 genomic library. The deduced amino acid sequence of the U. maydis gene showed homology to P450_14DMs from other organisms and contained specific motifs which were hallmarks of P450s. Expression of the gene in an U. maydis mutant (A20) deficient in P450_14DM led to only a partial restoration of P450_14DM activity. Accumulation of ergosta-7,22-dienol and ergost-7-enol in A20 transformants containing the ERG11 gene implied that an additional mutation affecting sterol Δ^5,6-desaturase activity accompanied the P450_14DM lesion.

Author Keywords: Ergosterol biosynthesis mutant; Sterol 14α-demethylase gene; Ustilago maydis

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