Comparative Transcriptome Analysis to Reveal Differentially Expressed Cytochrome P450 in Response to Imidacloprid in the Aphid Lion, Chrysoperla zastrowi sillemi (Esben-Petersen)

SIMPLE SUMMARY: Chrysoperla zastrowi sillemi (CZS) is a generalist predator of arthropod pests in different crops and is distributed in wide geographical regions. Being a natural predator, CZS shares an ecological niche with the pests and is exposed to several groups of pesticides including imidacloprid. Due to continuous exposure, it has developed resistance to several insecticides. Transcriptomes of imidacloprid-resistant and susceptible strains have been generated and compared for expression differences. From the transcriptome, sequences belonging to the CYP gene family have been mined for their nomenclature and classification into the four CYP clans. Putative functions of the CYP families in CZS have been identified by phylogenetic analysis including CYP sequences from Drosophila and Tribolium. Further, differential expressions of CYP genes have been validated using qRT-PCR. We found nine CYP genes to be downregulated and one to be upregulated after imidacloprid treatment. The information from current study can be exploited for the effective implementation of IPM as it aims at sustainable and eco-friendly crop yield improvement. ABSTRACT: The aphid lion, Chrysoperla zastrowi sillemi (Neuroptera: Chrysopidae) is a highly effective beneficial predator of many agricultural pests and has developed resistance to several insecticides. Understanding the molecular mechanism of insecticide resistance in the predators is crucial for its effective application in IPM programs. Therefore, transcriptomes of imidacloprid-resistant and susceptible strains have been assessed using RNA-seq. Cytochrome P450 is one of the important gene families involved in xenobiotic metabolism. Hence, our study focused on the CYP gene family where mining, nomenclature, and phylogenetic analysis revealed a total of 95 unique CYP genes with considerable expansion in CYP3 and CYP4 clans. Further, differential gene expression (DGE) analysis revealed ten CYP genes from CYP3 and CYP4 clans to be differentially expressed, out of which nine genes (CYP4419A1, CYP4XK1, CYP4416A10, CYP4416A-fragment8, CYP6YL1, CYP6YH6, CYP9GK-fragment16, CYP9GN2, CYP9GK6) were downregulated and one (CYP9GK3) was upregulated in the resistant strain as compared to the susceptible strain. Expression validation by quantitative real-time PCR (qRT-PCR) is consistent with the DGE results. The expansion and differential expression of CYP genes may be an indicator of the capacity of the predator to detoxify a particular group of insecticides.