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Keywords:

  • odourant-degrading enzymes;
  • cytochrome P450;
  • olfaction;
  • Mamestra brassicae

Abstract

The involvement of cytochrome P450 enzymes in olfaction was demonstrated in vertebrates some time ago. In insects these enzymes are well known for their role in insecticide resistance, but the involvement of P450 in pheromone degradation was only recently demonstrated. Using a PCR strategy, we have isolated two cDNAs from the antennae of the cabbage armyworm Mamestra brassicaeCYP4L4 and CYP4S4– which encode microsomal P450s. CYP4S4 expression is restricted to the antennae, whereas CYP4L4 is also found in the proboscis and legs. Moreover, the two genes are strongly expressed in one type of sensory unit of the antennae – the sensilla trichodea – which are tuned to the detection of odourants. The putative function of the corresponding enzymes is discussed with regard to their respective expression patterns.