Overexpression of the sterol 14α-demethylase gene (MgCYP51) in Mycosphaerella graminicola isolates confers a novel azole fungicide sensitivity phenotype.
Pest Manag Sci
; 68(7): 1034-40, 2012 Jul.
Article
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| MEDLINE
| ID: mdl-22411894
ABSTRACT
BACKGROUND:
The recent evolution towards resistance to azole fungicides in European populations of the wheat pathogen Mycosphaerella graminicola has been caused by the progressive accumulation of mutations in MgCYP51 gene, encoding the azole target sterol 14α-demethylase. Particular combinations of mutations have been shown specifically to affect the interaction of the MgCYP51 protein with different members of the azole class. Although additional mechanisms, including increased MgCYP51 expression and enhanced active efflux, have been proposed, the genetic changes underlying these mechanisms are unknown.RESULTS:
Analysis of the azole sensitivities of recent M. graminicola isolates identified a novel phenotype, seemingly independent of changes in MgCYP51 coding sequence. Characterised by a 7-16-fold reduction in in vitro sensitivity to all azoles tested and by growth on seedlings at higher doses of azoles in glasshouse tests compared with isolates carrying the same MgCYP51 variant (L50S, S188N, I381V, ΔY459/G460, N513K), isolates with this phenotype constitutively overexpress MgCYP51 by between 10- and 40-fold compared with the wild type. Analysis of sequences upstream of the predicted MgCYP51 translation start codon identified a novel 120 bp indel, considered to be an insertion, in isolates overexpressing MgCYP51.CONCLUSIONS:
The identification of an insertion in the predicted MgCYP51 promoter in azole-resistant isolates overexpressing MgCYP51 is the first report of a genetic mechanism, other than changes in target-site coding sequence, affecting sensitivity to multiple azoles in field isolates of M. graminicola. The identification of recent isolates overexpressing MgCYP51 confirms the ongoing evolution and diversification of resistance mechanisms in European populations of M. graminicola.
Texto completo:
1
Bases de datos:
MEDLINE
Asunto principal:
Ascomicetos
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Azoles
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Regulación Fúngica de la Expresión Génica
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Farmacorresistencia Fúngica
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Esterol 14-Desmetilasa
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Fungicidas Industriales
Tipo de estudio:
Diagnostic_studies
Idioma:
En
Revista:
Pest Manag Sci
Asunto de la revista:
TOXICOLOGIA
Año:
2012
Tipo del documento:
Article
País de afiliación:
Reino Unido