Abstract

Summary A large number of noncoding circular RNA s (circ RNA s) with regulatory potency have been identified in animals, but little attention has been given to plant circ RNA s. We performed genome‐wide identification of circ RNA s in Oryza sativa and Arabidopsis thaliana using publically available RNA ‐Seq data, analyzed and compared features of plant and animal circ RNA s. circ RNA s (12037 and 6012) were identified in Oryza sativa and Arabidopsis thaliana , respectively, with 56% (10/18) of the sampled rice exonic circ RNA s validated experimentally. Parent genes of over 700 exonic circ RNA s were orthologues between rice and Arabidopsis , suggesting conservation of circ RNA s in plants. The introns flanking plant circ RNA s were much longer than introns from linear genes, and possessed less repetitive elements and reverse complementary sequences than the flanking introns of animal circ RNA s. Plant circ RNA s showed diverse expression patterns, and 27 rice exonic circ RNA s were found to be differentially expressed under phosphate‐sufficient and ‐starvation conditions. A significantly positive correlation was observed for the expression profiles of some circ RNA s and their parent genes. Our results demonstrated that circ RNA s are widespread in plants, revealed the common and distinct features of circ RNA s between plants and animals, and suggested that circ RNA s could be a critical class of noncoding regulators in plants.