Full-length transcriptome-referenced analysis reveals developmental and olfactory regulatory genes in Dermestes frischii.

Dermestes frischii Kugelann, 1792 is a storage pest worldwide, and is important for estimating the postmortem interval in forensic entomology. However, because of the lack of transcriptome and genome resources, population genetics and biological control studies on D. frischii have been hindered. Here, single-molecule real-time sequencing and next-generation sequencing were combined to generate the full-length transcriptome of the five developmental stages of D. frischii, namely egg, young larva, mature larva, pupa and adult. A total of 41,665 full-length non-chimeric sequences and 59,385 non-redundant transcripts were generated, of which 42,756 were annotated in public databases. Using the weighted gene co-expression network analysis, gene co-expression modules related to the five developmental stages were constructed and screened, and the genes in these modules were subjected to Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses. The expression patterns of the differentially expressed genes (DEGs) related to olfaction and insect hormone biosynthesis were also explored. Transcription of most odorant binding proteins was up-regulated in the adult stage, suggesting they are important for foraging in adults. Many genes encoding for the ecdysone-inducible protein were up-regulated in the pupal stage, may be mainly responsible for the tissue remodelling of metamorphosis. The results of the quantitative real-time polymerase chain reaction (qRT-PCR) were consistent with the RNA-seq results. This is the first full-length transcriptome sequencing of dermestids, and the data obtained here are vital for understanding the stage-specific development and olfactory system of D. frischii, providing valuable resources for storage pest and forensic research.