Comparative RNA-sequencing profiling reveals novel Delta-class glutathione S-transferases relative genes expression patterns in Tribolium castaneum

Glutathione S-transferases (GSTs) are a large group of enzymes having both detoxification roles conferring insecticide resistance and specialist metabolic functions. Tribolium castaneum GST Delta 1 (TcGSTd1) has been found playing crucial role in insecticide resistance and biological processes in insect species. However, the regulatory system of TcGSTd1 has still rarely been known. Comparing the transcriptome profile of RNAi treated larvae (ds-TcGSTd1) and control larvae of T. canstaneum by using RNA-sequencing, we obtained 14,284,085 sequence reads aligned with 13,275 genes. And 512 differentially expressed genes (DEGs) were identified from ds-TcGSTd1 treated group. Est/CCE, CYP, MRPs were significantly down-regulated in ds-TcGSTd1 group when compared with control group, which illustrated that they cooperated with TcGSTd1 to reduce the activity of cellular metabolism system. While, SNO was up-regulated in ds-TcGSTd1 insects suggested it may also involve in detoxifying alkaloid of insect metabolism system. These results established that TcGSTd1 not only acts as a vital gene for phase II cellular detoxification but also participates in phase 0, I, and III cellular detoxification by cooperating with CSPs, OBPs, CYP9, ESTB1, CCE6, MRPs and other detoxification genes. Knockdown of TcGSTd1 also suppressed several genes encoding antioxidant enzymes, e.g. CuZnSOD, Duox, Prx, HPX, CPO, and MCORP. Suggested that they may modulate the function of TcGSTd1 on lifespan, immune, development and reproduction. All these results shed the new insights into the regulatory mechanism of TcGSTd1 involved in insect physiology and could further facilitate the research of suitable and sustainable managements for the pest control.