Identification and functional prediction of sugar beet circRNAs involved in drought responses

Abstract

Drought is one of the most common abiotic constraints on the quality and productivity of crops on a global scale. Despite the rapidly updating information on circRNAs (circular RNAs), their roles in the anti-drought regulation of sugar beet are least understood. As a newly recognized class of non-coding RNAs, circRNAs exert crucial effects on miRNA (microRNA) functionality, as well as on transcriptional regulation. To clarify the mechanism of how circRNAs of sugar beet respond to drought stress, deep sequencing was employed to characterize these circRNAs in a genome-wide manner under drought treatment. Our results identify a total of 17 differentially expressed circRNAs. As revealed by the Kyoto Encyclopedia of Genes and Genomes and Gene Ontology outcomes, circRNAs were found capable and involved in drought-responsive events. Utilizing the target genes exhibiting direct/indirect associations with drought resistance, we established a circRNA–miRNA–mRNA meshwork based on the circRNAs that were expressed differentially. The probable sponge functions of novel_circ_0000442 and novel_circ_0000443 were exerted by targeting ath-miR157d. This helped regulate the expression of relevant target genes, including BVRB_1 g004570, BVRB_1 g005450, and BVRB_1 g005790, that were involved in drought response. Apart from offering novel understandings of anti-drought mechanisms, our findings lay a basis for probing deeper into the intricate regulatory networks of sugar beet genes.