Identification of differentially expressed microRNAs under imidacloprid exposure in Sitobion avenae Fabricius

Background: MicroRNAs (miRNAs), which are short single-stranded non-coding RNAs, regulate the expression of target genes, especially those involved in the regulation or metabolism of endogenous or xenobiotic compounds. Results: De novo assemblies of the transcriptome of Sitobion avenae Fabricius under control conditions and under imidacloprid treatment were obtained using Illumina short-read sequencing technology. Fifty-seven miRNAs, of which 36 were known and 21 were novel, were identified. Quantitative analysis of miRNA levels showed that 5 miRNAs were significantly up-regulated, and 11 miRNAs were significantly down-regulated in the nymphs of S. avenae treated with imidacloprid in comparison with those of the control. Analysis of the candidate target genes in S. avenae that could be regulated by these miRNAs were also carried out. The functions of the miRNAs, which could potentially regulate target genes that participate in metabolism, regulatory or detoxification pathways in S. avenae, were clarified based on Gene Ontology and KEGG pathway analysis. The effects of the miRNAs api-miR-1000, api-miR-316, and api-miR-iab-4 on susceptibility of S. avenae to imidacloprid was determined. Modulation of the abundances of api-miR-1000, api-miR-316, and api-miR-iab-4 by the addition of the correspondign inhibitors to the artificial diet significantly changed the susceptibility of S. avenae to imidacloprid, which further demonstrated the effect of these miRNAs on the regulation or metabolism of insecticides.Conclusion: The results of this study suggested that miRNAs differentially expressed in response to imidacloprid could play a critical regulatory role in the resistance of S. avenae to imidacloprid.