Identification and characterization of conserved and novel microRNAs in Xanthoceras sorbifolium via deep sequencing

Xanthoceras sorbifolium is an economically important woody plant in China. Plant microRNAs (miRNAs) play a vital role in plant development. We used Solexa technology to sequence a small RNA library from the buds, young and mature leaves, flowers, and developing seeds (10, 30, and 60 days after pollination) of X. sorbifolium to identify conserved and novel miRNAs. Sequence analysis identified 49 conserved miRNAs belonging to 19 miRNA families, as well as four novel miRNAs. An analysis of 10 miRNA sequences by qRT-PCR showed that all sequences were expressed and that they were dynamically regulated in different tissues. Finally, seven targets of the novel miRNAs were predicted. This study opens up a new avenue for understanding the roles of miRNAs in X. sorbifolium.