Background: Recently, identification and functional studies of circular RNAs, a type of
non-coding RNAs arising from a ligation of 3’ and 5’ ends of a linear RNA molecule, were conducted
in mammalian cells with the development of RNA-seq technology.
Method: Since compared with animals, studies on circular RNAs in plants are less thorough, a genome-
wide identification of circular RNA candidates in Arabidopsis was conducted with our own developed
bioinformatics tool to several existing RNA-seq datasets specifically for non-coding RNAs.
Results: A total of 164 circular RNA candidates were identified from RNA-seq data, and 4 circular
RNA transcripts, including both exonic and intronic circular RNAs, were experimentally validated.
Interestingly, our results show that circular RNA transcripts are enriched in the photosynthesis system
for the leaf tissue and correlated to the higher expression levels of their parent genes. Sixteen out of
all 40 genes that have circular RNA candidates are related to the photosynthesis system, and out of
the total 146 exonic circular RNA candidates, 63 are found in chloroplast.