Circular RNA, circ1-3p, is Involved in Cyflumetofen Resistance by Acting as a Competitive RNA against miR-1-3p in Tetranychus cinnabarinus

As a newly recognized type of noncoding RNA, circular RNA can mediate a variety of physiological changes in mammals by regulating the post-transcriptional expression level of genes. However, the function of circRNA in the evolution of pesticide resistance in arthropods is still unknown. In this study, 2546 circRNAs were identified in Tetranychus cinnabarinus by transcriptome sequencing. The differentially expressed gene analysis indicated that 44 circRNAs were overexpressed in a cyflumetofen-resistant strain, of which a circRNA (named circ1-3p) was found to contain the response elements of miR-1-3p, an miRNA that is involved in cyflumetofen resistance by targeting TcGSTm04. The circular structure of circ1-3p was further determined using a divergent primer. The results of different molecular assays in vitro and in vivo showed that circ1-3p can compete with TcGSTm04 in miR-1-3p binding. The colocalization of circ1-3p and miR-1-3p was found using fluorescence in situ hybridization, suggesting that circ1-3p can directly sponge miR-1-3p in T. cinnabarinus. In addition, silencing the expression of circ1-3p resulted in the upregulation of miR-1-3p and the downregulation of TcGSTm04 as well as a significant increase in the sensitivity of T. cinnabarinus to cyflumetofen. All these pieces of evidence indicates that overexpressed circ1-3p promotes the expression of TcGSTm04 through sponging miR-1-3p, thereby involving in the evolution of cyflumetofen resistance in T. cinnabarinus.