Transcriptome-Wide Identification and Characterization of Circular RNAs in Leaves of Chinese Cabbage (Brassica rapa L. ssp. pekinensis) in Response to Calcium Deficiency-Induced Tip-burn

Abstract

Abstract Circular RNA (circRNA) is a newly discovered non-coding RNA, which play significant roles in the function and transcriptional regulation of microRNA. To date, in Chinese cabbage, the functional characteristic of circRNAs in response to calcium deficiency-induced tip-burn have not been reported. In this study, 730 circRNAs were isolated from Chinese cabbage leaves, of which 23 and 22 were differentially expressed in different calcium deficiency stages compared with the control. Forty-six host genes of the differentially expressed circRNAs were identified, and one circRNA was found to act as miRNAs sponges. Based on the functional analysis of host genes and target mRNAs of the corresponding miRNAs, the identified circRNAs might participated in response to stimulus, electron carrier activity, ATPase activity, cell wall metabolism, transcription factors and plant hormone signal transduction. ABF2 , a positive regulator of the abiotic stress response in the abscisic acid (ABA) pathway, may play a role in calcium deficiency tolerance through a circRNA regulatory pathway. Correspondingly, the concentration of ABA is also increased during the Ca 2+ deficiency stress. Our results suggest that circRNAs participate in a broad range of biological processes and physiological functions in the response to calcium deficiency-induced tip-burn and provide a basis for further studies of the biological roles that circRNAs play in the plant stress response.