GEPHE SUMMARY Print
Gephebase Gene
Entry Status
Published
GepheID
GP00002477
Main curator
Courtier
PHENOTYPIC CHANGE
Trait Category
Trait State in Taxon A
Helicoverpa armigera - susceptible
Trait State in Taxon B
Helicoverpa armigera - resistant strain from Australia - allele CYP337B1v1
Ancestral State
Taxon A
Taxonomic Status
Taxon A
Common Name
cotton bollworm
Synonyms
Heliothis (Helicoverpa) armigera; Heliothis armigera; cotton bollworm; American bollworm; corn ear worm; scarce bordered straw; tobacco budworm; Helicoverpa armigera (Hubner, 1808)
Rank
species
Lineage
Show more ... da; Insecta; Dicondylia; Pterygota; Neoptera; Holometabola; Amphiesmenoptera; Lepidoptera; Glossata; Neolepidoptera; Heteroneura; Ditrysia; Obtectomera; Noctuoidea; Noctuidae; Heliothinae; Helicoverpa
NCBI Taxonomy ID
is Taxon A an Infraspecies?
No
Taxon B
Common Name
cotton bollworm
Synonyms
Heliothis (Helicoverpa) armigera; Heliothis armigera; cotton bollworm; American bollworm; corn ear worm; scarce bordered straw; tobacco budworm; Helicoverpa armigera (Hubner, 1808)
Rank
species
Lineage
Show more ... da; Insecta; Dicondylia; Pterygota; Neoptera; Holometabola; Amphiesmenoptera; Lepidoptera; Glossata; Neolepidoptera; Heteroneura; Ditrysia; Obtectomera; Noctuoidea; Noctuidae; Heliothinae; Helicoverpa
NCBI Taxonomy ID
is Taxon B an Infraspecies?
No
GENOTYPIC CHANGE
UniProtKB
Helicoverpa armigera
GenebankID or UniProtKB
Helicoverpa armigera
Presumptive Null
No
Molecular Type
Aberration Type
Molecular Details of the Mutation
The unique P450 chimeric gene CYP337B3 arose from unequal crossing-over between two parental P450 genes CYP337B2 and CYP337B1 . CYP337B3 can metabolize pyrethroids in vitro. Neither parental enzyme has the ability to metabolize pyrethroids in vitro. The exclusive presence of CYP337B3 in resistant insects of this strain confers a 42-fold resistance to fenvalerate.
Experimental Evidence
Authors
Joußen N; Agnolet S; Lorenz S; Schöne SE; Ellinger R; Schneider B; Heckel DG
Abstract
Worldwide, increasing numbers of insects have evolved resistance to a wide range of pesticides, which hampers their control in the field and, therefore, threatens agriculture. Members of the carboxylesterase and cytochrome P450 monooxygenase superfamilies are prominent candidates to confer metabolic resistance to pyrethroid insecticides. Both carboxylesterases and P450 enzymes have been shown to be involved in pyrethroid resistance in Australian Helicoverpa armigera, the noctuid species possessing by far the most reported resistance cases worldwide. However, specific enzymes responsible for pyrethroid resistance in field populations of this species have not yet been identified. Here, we show that the resistance toward fenvalerate in an Australian strain of H. armigera is due to a unique P450 enzyme, CYP337B3, which arose from unequal crossing-over between two parental P450 genes, resulting in a chimeric enzyme. CYP337B3 is capable of metabolizing fenvalerate into 4'-hydroxyfenvalerate, which exhibits no toxic effect on susceptible larvae; enzymes from the parental P450 genes showed no detectable fenvalerate metabolism. Furthermore, a polymorphic H. armigera strain could be bred into a susceptible line possessing the parental genes CYP337B1 and CYP337B2 and a resistant line possessing only CYP337B3. The exclusive presence of CYP337B3 in resistant insects of this strain confers a 42-fold resistance to fenvalerate. Thus, in addition to previously documented genetic mechanisms of resistance, recombination can also generate selectively advantageous variants, such as this chimeric P450 enzyme with an altered substrate specificity leading to a potent resistance mechanism.
EXTERNAL LINKS
COMMENTS
@Parallelism - Resistance to pyrethroids as a result from the formation of a chimeric P450 gene CYP337B3 has arisen multiple times during evolution of the cotton bollworm H. armigera.
YOUR FEEDBACK is welcome!