Analysis of the NADPH cytochrome P45 reductase gene: its relationship with pyrethroid resitance in the Chagas disease vector Triatoma infestans

VARELA, GM; GARCIA, BA; GROSSO, CG; STROPPA, MM

Buenos Aires

Congreso; Reunión Conjunta de las Sociedades de Biociencias; 2017

Pyrethroid resistance has been detected in the Chagas disease vector Triatoma infestans (Hemiptera: Reduviidae), which has been attributed to target site insensitivity and increased oxidative metabolism of the insecticide by cytochrome P450s. NADPH cytochrome P450 reductase (CPR) plays an essential role in transferring electrons from NADPH to the P450-substrate complex. In this study, the full length CPR cDNA of T. infestans was isolated and gene expression was determined by quantitative PCR. The open reading frame is 2046 bp long, encoding a protein of 682 amino acids. Amino acid sequence analysis indicates that the T. infestansCPR and the putative Rhodnius prolixus and Triatoma dimidiata CPRs, present conserved ligand-binding domains. The expression of the CPR gene at transcriptional level was determined in muscle,heads, gonads and fat body of fifth instar nymphs and adults. In both stages, gonads and fat body presented significant levels of expression. It was detected a higher level of expression in gonads of nymphs than in adults, while the fat body presented a higher level of expression in adults. On the other hand, congruently with a previous study of our laboratory, in which the expression of three cytochrome P450 genes (CYP4EM7, CYP3085B1, and CYP3092A6 genes) was induced by deltamethrin, the levels of T. infestans CPR mRNA were up-regulated in the fat body of fifth instar nymphs after topical application of deltamethrin. Besides, similarly to the observed in the CYP4EM7 gene, it was detected overexpression of the CPR gene inthe most resistant strain of T. infestans included in the study. Theseresults suggest that CPR plays an essential role in P450-mediatedresistance of T. infestans to insecticides.