PLoS ONE (2012) 7 (2 - e31077)

Nikos Karatolos, Martin S. Williamson, Ian Denholm, Kevin Gorman, Richard H. ffrench-Constant and Chris Bass (2012)
Over-expression of a cytochrome P450 is associated with resistance to pyriproxyfen in the greenhouse whitefly Trialeurodes vaporariorum
PLoS ONE 7 (2 - e31077)
Abstract:
Background
The juvenile hormone mimic, pyriproxyfen is a suppressor of insect embryogenesis and development, and is effective at controlling pests such as the greenhouse whitefly Trialeurodes vaporariorum (Westwood) which are resistant to other chemical classes of insecticides. Although there are reports of insects evolving resistance to pyriproxyfen, the underlying resistance mechanism(s) are poorly understood.
Results
Bioassays against eggs of a German (TV8) population of T. vaporariorum revealed a moderate level (21-fold) of resistance to pyriproxyfen. This is the first time that pyriproxyfen resistance has been confirmed in this species. Sequential selection of TV8 rapidly generated a strain (TV8pyrsel) displaying a much higher resistance ratio (>4000-fold). The enzyme inhibitor piperonyl butoxide (PBO) suppressed this increased resistance, indicating that it was primarily mediated via metabolic detoxification. Microarray analysis identified a number of significantly over-expressed genes in TV8pyrsel as candidates for a role in resistance including cytochrome-P450 dependent monooxygenases (P450s). Quantitative PCR highlighted a single P450 gene (CYP4G61) that was highly over-expressed (81.7-fold) in TV8pyrsel.
Conclusion
Over-expression of a single cytochrome P450 gene (CYP4G61) has emerged as a strong candidate for causing the enhanced resistance phenotype. Further work is needed to confirm the role of the encoded P450 enzyme CYP4G61 in detoxifying pyriproxyfen.
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Full text of article
Database assignments for author(s): Ian Denholm, Martin S. Williamson, Kevin Gorman, Nikos Karatolos

Research topic(s) for pests/diseases/weeds:
pesticide resistance of pest

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Trialeurodes vaporariorum		Germany
	Trialeurodes vaporariorum	Beans (Phaseolus)	United Kingdom