Identification and characterization of circRNAs in Pyrus betulifolia Bunge under drought stress.

Circular RNAs (circRNAs) play important roles in miRNA function and transcriptional control. However, little is known regarding circRNAs in the pear. In this study, we identified circRNAs using deep sequencing and analyzed their expression under drought stress. We identified 899 circRNAs in total, among which 33 (23 upregulated, 10 downregulated) were shown to be dehydration-responsive. We performed GO and KEGG enrichment analysis to predict the functions of differentially expressed circRNAs. 309 circRNAs were predicted to act as sponges for 180 miRNAs. A circRNA-miRNA co-expression network was constructed based on correlation analysis between the differentially expressed circRNAs and their miRNA binding sites. Our study will provide a rich genetic resource for the discovery of genes related to drought stress, and can readily be applied to other fruit trees