Scott_2003_Insect.Biochem.Mol.Biol_33_139

It was recently proposed that a mutation (G137D) in the MdalphaE7 gene was responsible for increasing transcription of a P450 (CYP6A1) resulting in resistance to diazinon. To examine if MdalphaE7 had a role in resistance in other strains we sequenced a fragment (approximately 700 bp) of the MdalphaE7 gene from individual flies of two insecticide susceptible and three insecticide resistant (due to increased monooxygenase-mediated detoxification) strains. Five unique alleles were discovered. While all of the susceptible strains had Gly137, so did the resistant LPR and NG98 strains. Of the two alleles in the YPER strain one had the G137D substitution and the other did not. Based on the lack of correlation between the presence of the 'mutant' MdalphaE7 and resistance (or P450 levels), we conclude that the G137D mutation in MdalphaE7 is not involved in transcriptional control of the P450s involved in resistance in the LPR, NG98 or YPER strains. The relationship between MdalphaE7 alleles and insecticide resistance is discussed in light of these findings.