Overexpressed esterases in a fenvalerate resistant strain of the cotton bollworm, Helicoverpa armigera.
Insect Biochem Mol Biol
; 41(1): 14-21, 2011 Jan.
Article
en En
| MEDLINE
| ID: mdl-20875855
ABSTRACT
Enhanced detoxification is the major mechanism responsible for pyrethroid resistance in Chinese populations of Helicoverpa armigera. Previous work has shown that enhanced oxidation contributes to resistance in the fenvalerate-selected Chinese strain, YGF. The current study provides evidence that enhanced hydrolysis by esterase isozymes also contributes to the resistance in this strain. The average esterase activity of third instar YGF larvae was 1.9-fold compared with that of a susceptible SCD strain. Much of this difference was attributed to isozymes at two zones which hydrolysed the model carboxylester substrate 1-naphthyl acetate and also a 1-naphthyl analogue of fenvalerate. A preparation enriched for enzymes migrating to one of these zones from YGF was shown to hydrolyse fenvalerate with a specific activity of about 2.9 nmol/min/mg. This material was also matched by mass spectrometry with four putative carboxylesterase genes, all of which clustered within a phylogenetic clade of secreted midgut esterases. Quantitative PCR on these four genes showed several-fold greater expression in tissues of YGF compared to SCD but no differences was found in the number of copies of the genes between the strains.
Texto completo:
1
Bases de datos:
MEDLINE
Asunto principal:
Genes de Insecto
/
Esterasas
/
Mariposas Nocturnas
Límite:
Animals
País/Región como asunto:
Asia
Idioma:
En
Revista:
Insect Biochem Mol Biol
Asunto de la revista:
BIOLOGIA MOLECULAR
/
BIOQUIMICA
Año:
2011
Tipo del documento:
Article
País de afiliación:
China