show Abstracthide AbstractSynergists can counteract metabolic insecticide resistance by inhibiting detoxification enzymes or transporters. In this study we used Illumina RNA-sequencing to investigate genome-wide transcriptional responses in an acaricide resistant strain (JP-R) of the spider mite Tetranychus urticae upon exposure to synergists such as S,S,S-tributyl phosphorotrithioate (DEF), diethyl maleate (DEM), piperonyl butoxide (PBO) and cyclosporin A (CsA). Overall design: In total 24 RNA-seq samples (6 treatments, 4 biological replicates per treatment) from Tetranychus urticae, were generated. RNA was collected from adult T. urticae females 24h after being sprayed with a synergist compound (PBO, DEF, DEM or CsA) or with formulation only (FORM). Unsprayed mites served as an additional control (CON). For each sample, Illumina mRNA-seq libraries were constructed and strand-specific paired reads of 2x125 bp were generated. The obtained reads were used to quantify gene expression in each sample.