Insecticide resistance at the surface: Contribution of the integument genes in Triatoma infestans

JUÁREZ, M. PATRICIA; CALDERÓN FERNÁNDEZ, GUSTAVO M.

Orlando

Congreso; International Congress of Entomology; 2016

Entomological Society of America

Introduction: The integument plays a crucial role in the fitness, general metabolism, communication and survival of insects. Recent evidence also suggests that this tissue participates in several aspects of insecticide resistance. Higher cuticle hydrocarbon content and a significant cuticle thickening were detected in pyrethroid-resistant compared to pyrethroid-susceptible Triatoma infestans specimens. Among key enzymes involved in insect cuticle lipid biosynthesis, fatty acid synthases (FAS) and elongases (ELOVL) provide the fatty acyl precursors to the formation of hydrocarbons and other major cuticle lipid components. The bulk of cuticle is formed by structural proteins representing several families of chitin-binding proteins; the most relevant belong to the CPR and CPAP families.Methods: After a transcriptome analysis of the T. infestans integument, the sequences of genes related both to cuticle lipid biosynthesis and cuticle structure, as well as to insecticide detoxification, were obtained. The expression pattern was analyzed by real-time PCR (qPCR).Results/Conclusion: Several genes showed a differential expression pattern in pyrethroid-resistant compared to pyrethroid-susceptible insects. These results support previous evidences in T. infestans and suggest that cuticle insecticide resistance is related not only to mechanisms involved in a delayed penetration through the cuticle, but also to enhanced detoxification as the insecticide is transported through the epidermis.