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Characterization of the sterol 14α‐demethylases of Fusarium graminearum identifies a novel genus‐specific CYP 51 function
Author(s) -
Fan Jieru,
Urban Martin,
Parker Josie E.,
Brewer Helen C.,
Kelly Steven L.,
HammondKosack Kim E.,
Fraaije Bart A.,
Liu Xili,
Cools Hans J.
Publication year - 2013
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.12193
Subject(s) - biology , sterol , demethylase , ergosterol , mutant , saccharomyces cerevisiae , lanosterol , fusarium , squalene monooxygenase , ascospore , biochemistry , yeast , virulence , microbiology and biotechnology , gene , genetics , biosynthesis , epigenetics , spore , cholesterol
SummaryCYP 51 encodes the cytochrome P450 sterol 14α‐demethylase, an enzyme essential for sterol biosynthesis and the target of azole fungicides. In Fusarium species, including pathogens of humans and plants, three CYP 51 paralogues have been identified with one unique to the genus. Currently, the functions of these three genes and the rationale for their conservation within the genus Fusarium are unknown. Three Fusarium graminearum CYP 51 s ( Fg CYP 51 s) were heterologously expressed in Saccharomyces cerevisiae . Single and double Fg CYP 51 deletion mutants were generated and the functions of the Fg CYP 51 s were characterized in vitro and in planta . Fg CYP 51A and Fg CYP 51B can complement yeast CYP 51 function, whereas Fg CYP 51C cannot. Fg CYP 51A deletion increases the sensitivity of F. graminearum to the tested azoles. In ΔFg CYP 51B and ΔFg CYP 51 BC mutants, ascospore formation is blocked, and eburicol and two additional 14‐methylated sterols accumulate. Fg CYP 51C deletion reduces virulence on host wheat ears. Fg CYP 51B encodes the enzyme primarily responsible for sterol 14α‐demethylation, and plays an essential role in ascospore formation. Fg CYP 51A encodes an additional sterol 14α‐demethylase, induced on ergosterol depletion and responsible for the intrinsic variation in azole sensitivity. Fg CYP 51C does not encode a sterol 14α‐demethylase, but is required for full virulence on host wheat ears. This is the first example of the functional diversification of a fungal CYP 51 .