Evaluating the insecticide resistance potential of eight Drosophila melanogaster cytochrome P450 genes by transgenic over-expression

Daborn, Phillip J.; Lumb, Christopher; Boey, Adrian; Wong, Wayn; ffrench-Constant, Richard H.; Batterham, Philip

doi:10.1016/j.ibmb.2007.02.008

Cited by 209 publications

(240 citation statements)

References 54 publications

(76 reference statements)

Supporting

Mentioning

226

Contrasting

Unclassified

Order By: Relevance

“…These cases of P450 gene duplication associated with insecticide resistance suggest that P450 gene duplication could potentially generate genes that are more metabolically active against insecticides. This is also supported by the observation made in Drosophila that both copies of CYP12D1 need to be overexpressed to confer a resistant phenotype (Daborn et al 2007). In humans, duplication of CYP2D6 results in an ultra-rapid metabolism of its substrates (Agundez et al 2001).…”

Section: Discussionmentioning

confidence: 61%

Two duplicated P450 genes are associated with pyrethroid resistance in Anopheles funestus, a major malaria vector

Wondji¹,

Irving²,

Morgan³

et al. 2009

Genome Res.

218

246

View full text Add to dashboard Cite

Pyrethroid resistance in Anopheles funestus is a potential obstacle to malaria control in Africa. Tools are needed to detect resistance in field populations. We have been using a positional cloning approach to identify the major genes conferring pyrethroid resistance in this vector. A quantitative trait locus (QTL) named rp1 explains 87% of the genetic variance in pyrethroid susceptibility in two families from reciprocal crosses between susceptible and resistant strains. Two additional QTLs of minor effect, rp2 and rp3, were also detected. We sequenced a 120-kb BAC clone spanning the rp1 QTL and identified 14 protein-coding genes and one putative pseudogene. Ten of the 14 genes encoded cytochrome P450s, and expression analysis indicated that four of these P450s were differentially expressed between susceptible and resistant strains. Furthermore, two of these genes, CYP6P9 and CYP6P4, which are 25 and 51 times overexpressed in resistant females, are tandemly duplicated in the BAC clone as well as in laboratory and field samples, suggesting that P450 gene duplication could contribute to pyrethroid resistance in An. funestus. Single nucleotide polymorphisms (SNPs) were identified within CYP6P9 and CYP6P4, and genotyping of the progeny of the genetic crosses revealed a maximum penetrance value f 2 = 1, confirming that these SNPs are valid resistance markers in the laboratory strains. This serves as proof of principle that a DNA-based diagnostic test could be designed to trace metabolic resistance in field populations. This will be a major advance for insecticide resistance management in malaria vectors, which requires the early detection of resistance alleles.

show abstract

Section: Discussionmentioning

confidence: 61%

Two duplicated P450 genes are associated with pyrethroid resistance in Anopheles funestus, a major malaria vector

Wondji¹,

Irving²,

Morgan³

et al. 2009

Genome Res.

218

246

View full text Add to dashboard Cite

show abstract

“…These data, and the fact that many other significant genes are involved in synaptic transmission, lead to a significant overrepresentation of a suite of synapse-related GO terms. The known examples of insecticide resistance alleles associated with acetylcholine metabolism in flies and mosquitoes (Fournier et al 1989;Weill et al 2002Weill et al , 2003 and the aforementioned significant Cyp6g1, which is also implicated in insecticide resistance (Chung et al 2007;Daborn et al 2007), suggest that selection pressures associated with insecticide or other environmental toxins vary with latitude.…”

Section: Resultsmentioning

confidence: 99%

Genomic Analysis of Adaptive Differentiation inDrosophila melanogaster

et al. 2008

View full text Add to dashboard Cite

Drosophila melanogaster shows clinal variation along latitudinal transects on multiple continents for several phenotypes, allozyme variants, sequence variants, and chromosome inversions. Previous investigation suggests that many such clines are due to spatially varying selection rather than demographic history, but the genomic extent of such selection is unknown. To map differentiation throughout the genome, we hybridized DNA from temperate and subtropical populations to Affymetrix tiling arrays. The dense genomic sampling of variants and low level of linkage disequilibrium in D. melanogaster enabled identification of many small, differentiated regions. Many regions are differentiated in parallel in the United States and Australia, strongly supporting the idea that they are influenced by spatially varying selection. Genomic differentiation is distributed nonrandomly with respect to gene function, even in regions differentiated on only one continent, providing further evidence for the role of selection. These data provide candidate genes for phenotypes known to vary clinally and implicate interesting new processes in genotype-by-environment interactions, including chorion proteins, proteins regulating meiotic recombination and segregation, gustatory and olfactory receptors, and proteins affecting synaptic function and behavior. This portrait of differentiation provides a genomic perspective on adaptation and the maintenance of variation through spatially varying selection.T HE amount and genomic distribution of polymorphism may be influenced by genetic drift, by mutation-selection balance, and by various forms of positive selection such as spatially varying selection, heterozygote advantage, or negative frequency-dependent selection. Spatially varying selection can generate allelefrequency differences between populations in spite of gene flow and lead to local adaptation, which is of particular interest as an intermediate step between intra-and interspecies variation (Felsenstein 1976;Endler 1977;Barton 1983).Drosophila melanogaster has been a model system for investigating the forces maintaining polymorphism for many decades. Indeed, differentiation along latitudinal clines in this species is one of the most thoroughly documented cases of spatially varying selection ( and Singh 1991;Berry and Kreitman 1993;Long and Singh 1995;Gockel et al. 2002;Kennington et al. 2003). The observations that clinal variation is strongly associated with easily measurable phenotypes affecting fitness (Eanes 1999;Gockel et al. 2002;Calboli et al. 2003;Norry et al. 2004;Kennington et al. 2007) and that clines for a number of phenotypes and genetic variants appear to have been independently established on multiple continents (De Jong and Bochdanovits 2003) also strongly support the proposition that many clinal variants are under spatially varying selection and that the biology of temperate and tropical populations may be quite different.Nevertheless, these data represent a small and highly biased picture of the phenotypes and...

show abstract

“…For example, in a 2002 survey of 20 resistant and 20 susceptible strains collected from five continents, all 20 resistant strains showed overtranscription of Cyp6g1 (Daborn et al 2002). Similarly, when the genetic switch UAS:GAL4 was used to overexpress different P450s in genetically transformed Drosophila (Daborn et al 2007), other P450s could again confer resistance to DDT (e.g., CYP12D1) but, critically, none of these other P450s has been shown to be correlated with resistance in field-collected strains. Finally, to prove that CYP6G1 can actually metabolize DDT, the enzyme has been expressed in a heterolgous expression system and has been shown to convert DDT to DDD (1,1-dichloro-2,2-bis(p-chlorophenyl)ethane) via dechlorination (Joussen et al 2008).…”

mentioning

confidence: 99%

The Molecular Genetics of Insecticide Resistance

2013

View full text Add to dashboard Cite

The past 60 years have seen a revolution in our understanding of the molecular genetics of insecticide resistance. While at first the field was split by arguments about the relative importance of mono-vs. polygenic resistance and field-vs. laboratory-based selection, the application of molecular cloning to insecticide targets and to the metabolic enzymes that degrade insecticides before they reach those targets has brought out an exponential growth in our understanding of the mutations involved. Molecular analysis has confirmed the relative importance of single major genes in target-site resistance and has also revealed some interesting surprises about the multi-gene families, such as cytochrome P450s, involved in metabolic resistance. Identification of the mutations involved in resistance has also led to parallel advances in our understanding of the enzymes and receptors involved, often with implications for the role of these receptors in humans. This Review seeks to provide an historical perspective on the impact of molecular biology on our understanding of resistance and to begin to look forward to the likely impact of rapid advances in both sequencing and genome-wide association analysis."Curiouser and curiouser!" cried Alice.Lewis Carroll L ewis Carroll sent Alice down a rabbit hole without the least idea of what was to happen next, but as Alice ventured deeper into Wonderland things became "Curiouser and curiouser!" So indeed have studies on the molecular basis of insecticide resistance. While starting with rather simplistic expectations about the role of single mutations in single genes, resistance has been shown to involve a panoply of multiple mutations in multiple genes, often with independent and complex origins. This review will attempt to place these current findings into context and to examine the extent to which the field has often been historically blindsided by dogma. My arguments will encompass key controversies debated in the field such as the relative importance of mono-vs. polygenic resistance and the implications of resistance-associated mutations for whole-organism fitness in the absence of pesticide. Importantly, we will also examine the role of dogma in shaping the way that resistance research has been pursued over the past 50 years. Key questions addressed are therefore: How many mutations per gene cause resistance? How many mechanisms are there per species (genome)? How many independent genetic origins (mutations) give rise to each mechanism? What new mechanisms are still undiscovered and how might they arise? Monogenic vs. Polygenic ResistanceCrow, DDT, and DrosophilaThe humble fruit fly Drosophila melanogaster has been a key tool in unlocking the molecular basis of insecticide resistance, and early studies by James Crow and others have helped to establish Drosophila as a genetic model for resistance studies. Studies of DDT resistance in Drosophila have also typified arguments surrounding mono-vs. polygenic inheritance of insecticide resistance. In his pioneering review of in...

show abstract

Evaluating the insecticide resistance potential of eight Drosophila melanogaster cytochrome P450 genes by transgenic over-expression

Cited by 209 publications

References 54 publications

Two duplicated P450 genes are associated with pyrethroid resistance in Anopheles funestus, a major malaria vector

Two duplicated P450 genes are associated with pyrethroid resistance in Anopheles funestus, a major malaria vector

Genomic Analysis of Adaptive Differentiation inDrosophila melanogaster

The Molecular Genetics of Insecticide Resistance

Contact Info

Product

Resources

About