Piperonyl butoxide induces the expression of P450 and GST genes in Drosophila melanogaster

Piperonyl butoxide (PBO) is an insecticide synergist known to inhibit the activity of cytochrome P450 enzymes. PBO is currently used in many insecticide formulations, and has also been suggested as a pre-treatment in some pesticide applications. Little is known about how insects respond to PBO exposure at the gene transcription level. We have characterised the transcriptional response of the Drosophila melanogaster genome after PBO treatment, using both a custom designed “detox” microarray containing cytochrome P450 (P450), glutathione S-transferase (GST) and esterase genes, and a full genome microarray. We identify a subset of P450 and GST genes, along with additional metabolic genes, that are highly induced by PBO. The gene set is an extremely similar gene set to that induced by phenobarbital, a compound for which pre-treatment is known to confer tolerance to a range of insecticide compounds. The implications of the induction of gene families known to metabolise insecticides and the use of PBO in pest management programs are discussed. Keywords: Induction response after treatment by PBO Drosophila melanogaster adult males were exposed to PBO. 8 replicates of 50 individuals were exposed to PBO and an additional 8 replicates of 50 individuals were exposed to the appropriate control (that is the same exposure conditions, without the addition of the compound). For each compound, RNA was extracted from all of the 8 samples and then pooled, before labelling. For each experiment exposed/unexposed labelling dye swaps were used to account for potential differences in labelling efficiency.