GSE121938
Transcriptional analyses of different Chrysodeixis includens larvae (Lepidoptera: Noctuidae) unveil molecular resistance mechanism for pyrethroid resistance in Brazil
Purpose: To investigate resistance mechanisms among individuals that tolerate high doses of insecticides, we performed high-throughput RNA sequencing on two Brazilian populations of C. includens, that differ in susceptibility to pyrethroid ?-cyhalothrin. Methods: Two replicates of pool 4 larvae (third instar) of each population, susceptible (LAB) and resistant (MS), were dissected into two parts: head (enriched with neural tissue) and body (enriched with adipose and gut tissues). Paired-end libraries of head and body tissues, with an approximate average insert length of 300 bp, were sequenced on an Illumina HiSeq platform with 150 bp paired-end sequencing. Trimmed RNA-Seq reads from transcriptomes of head and body larvae were used to alings the reads in the reference transcriptome (GSE121104), using TopHat. Expression analysis between LAB and MS population and between tissues were performed on Cufflinks, where the FPKM (fragments per kilobase per million mapped reads) between transcriptomes were estimated. Results: . Our results revealed several potential molecular mechanisms that underlie their low susceptibility to pyrethroids. We identified 10 synonymous and five non-synonymous mutations within the coding region of the voltage-gated sodium channel in the resistant population, specifically in domains II, III, and IV. Additionally, we observed overexpression of metabolic enzymes including Cyp, Gst, Est, and Ugt. Some of these enzymes were up-regulated in the head as well as the abdomen of the resistant population, suggesting a detoxification process that begins in the mouth parts and continues through the gut. Conclusions: The complexity of altered gene expression and nonsynonymous mutations can effectively be assessed with RNA sequencing in order to implement integrated pest management strategies and insecticide resistance management. Overall design: Libraries of two replicates of pool 4 larvae (third instar) from head and body tissues were sequenced.