Identification of microRNAs and their targets in Vernicia fordii seeds by high-throughput sequencing. Vernicia fordii

The tung (Vernicia fordii) oil is a valuable industrial oil and has been considered to the production of biodiesel. Because of the poor agronomic traits of this crop, efforts have been made to transfer genes related to the production of its oil to higher yielding plants. However, the mechanisms highlighting gene expression in this plant is poorly understood. MicroRNAs are endogenously encoded small RNAs that play a key role in diverse plant biological processes. In order to identify and characterize miRNAs and their targets in V. fordii we generated by deep sequencing a sRNA and a mRNA library from mature seeds. Using sequence homology we identified 138 conserved plant miRNAs, which were distributed in 34 conserved miRNAs families. Further computation analysis allowed the prediction of secondary structures for 18 conserved and 14 novel miRNAs, as well as several miRNA variants (isomiRNAs). The predicted miRNA target genes are involved in a broad range of physiological functions, including growth and development, stress resistance and also lipid metabolism. This study presents the first identification of V. fordii miRNAs and contributes to understand the function of these miRNAs. Overall design: microRNA identification in a mature seed library of Vernicia fordii by deep sequencing (Illumina HiSeq2000).