Fig. 2

The distribution of circRNAs in different tissues and treatments and circRNAs validation. a Detected amount of circRNAs and their cognate supporting back-splicing junction reads. b Venn diagram showing the amount and distribution of circular RNAs in each tissues of cucumber under control and salt stress conditions. c Correlation of the abundance levels of circRNAs and their corresponding parental genes in cucumber. d Validation of cucumber circRNA through PCR and Sanger sequencing using Chr2:1524236|1525777 as an example. Upper left panel (Model), a model used to show the divergent primers for circRNAs backsplicing sites amplification. Upper right panel, an example showing that amplification of divergent primers can be amplified from cDNA but not from genomic DNA. Two middle panels, respectively, black rectangle (DNA sequence) representing downstream and upstream sequences in the genome, and red and green rectangles (circRNA sequence) representing back-splicing circRNA sequence. Lower panel, a Sanger sequencing example of cucumber circRNA Chr2:1524236|1525777. e M, marker; 1 to 35, thirty-five circRNA validation using Sanger sequencing. (Detailed information, including the corresponding ID of 1 to 35 circRNAs and their divergent primers, can be found in Additional file 3: Table S3)