This is the first report of an ABC transporter being associated with Bt resistance, but members of this family have previously been linked with pesticide resistance in insects. Increases in the expression of ABC transporters (P-glycoproteins, P-gp) were shown to be associated with resistance to chemical insecticides such as thiodicarb in Heliothis virescens (Lanning et al., 1996) and cypermethrin, fenvalerate and methylparathion in Helicoverpa armigera (Srinivas et al, 2004; Aurade et al., 2006). While these observations may explain cross-resistance for chemical insecticides, resistance to Bt appears to involve inactivation of a specific protein by truncation of the reading frame, so that no cross-resistance for both these insecticides and Bt will be observed. Nonetheless, the ability of members of this large multi-gene family to confer resistance through differing types of changes illustrates the challenge for pest control.

Aurade R, Jayalakshmi SK, Sreeramulu K (2006): Stimulatory effect of insecticides on partially purified P-glycoprotein ATPase from the resistant pest Helicoverpa armigera. Biochemistry and Cell Biology-Biochimie et Biologie Cellulaire 84:1045-1050.

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AbouDonia MB (1996): Tobacco budworm P-glycoprotein: Biochemical characterization and its involvement in pesticide resistance. Biochimica Et Biophysica Acta-General Subjects 1291:155-162.

Srinivas, R, Udikeri, SS, Jayalakshmi, SK, and Sreeramulu, K (2004): Identification of factors responsible for insecticide resistance in Helicoverpa armigera. Comp. Biochem. Physiol. C Toxicol. Pharmacol. 137: 261–269.