Large-scale identification of mirtrons in Arabidopsis and rice.

A new catalog of microRNA (miRNA) species called mirtrons has been discovered in animals recently, which originate from spliced introns of the gene transcripts. However, only one putative mirtron, osa-MIR1429, has been identified in rice (Oryza sativa). We employed a high-throughput sequencing (HTS) data- and structure-based approach to do a genome-wide search for the mirtron candidate in both Arabidopsis (Arabidopsis thaliana) and rice. Five and eighteen candidates were discovered in the two plants respectively. To investigate their biological roles, the targets of these mirtrons were predicted and validated based on degradome sequencing data. The result indicates that the mirtrons could guide target cleavages to exert their regulatory roles post-transcriptionally, which needs further experimental validation.