Transcriptome Analysis of Deltamethrin Resistance Mechanisms in Aedes aegypti Populations from Metro Manila, Philippines

Background: Arboviral transmission by Aedes aegypti is exacerbated by insecticide resistance, which undermines effective vector control strategies. In the Philippines, deltamethrin resistance in several Ae. aegypti populations has been reported and prompts an investigation into the possible molecular mechanisms involved. Methods: Two Ae. aegypti populations were subjected to susceptibility assays to deltamethrin and were RNA-sequenced for transcriptome analysis. Results: The two (2) Ae. aegypti populations were resistant to deltamethrin and had LC50 values of 1.26 and 2.15 μg/mL at the zeroth generation (G0) that shifted to 2.21 and 2.08 μg/mL at the second generation (G2) after sublethal deltamethrin exposure, although not statistically significant. Relative to a control population unexposed to any insecticide, DGE analysis of the RNA-Seq data revealed significant upregulation of cytochrome P450, glutathione S-transferase, and carboxyl/cholinesterase genes in resistant populations. Moreover, GO and KEGG analyses revealed enrichment of cytochrome P450-related terms and xenobiotic metabolism pathways. Conclusions: RNA-Seq analysis results of selected genes show concordance with their respective gene expression measured via qPCR (R = 0.89; p = 0.00049). This study provides insights into the possible molecular mechanisms of deltamethrin resistance in Philippine Ae. aegypti populations, providing informed decision-making in vector management.