Genome wide identification of circRNAs, miRNAs and their targets in tomatoes at heat, drought and their combination

Purpose: Circular RNAs (circRNAs) and microRNAs (miRNAs) play important roles in abiotic stress responses in plants. The aims of this study are to genome-widely identify the circRNAs, miRNAs and their targets in tomatoes at single heat, drought and their combination by high-throughput sequencing. Results: Following high-throughput sequencing, 765 miRNAs were identified in total with 335 conserved and 430 novel miRNAs in the 12 small-RNA libraries. Of these miRNAs, 32, 74 and 61 miRNAs were responsive to drought, heat and their combination, respectively. Following degradome sequencing, 50 sequences were identified as targets of 34 miRNAs in tomatoes at combined stress. Moreover, 467 circRNAs were identified in the 12 samples. Overall design: Methods: Tomato seedlings were treated at control, single heat, drought and their combination. Leaves from the tomato seedlings at four treatments were collected, frozen in liquid nitrogen and stored at -80 degrees Celsius before sequencing. Afterwards, the sRNA libraries of samples were constructed and sequenced with Illumina Hiseq2500 (LC-BIO, Hangzhou, China).