Characterizing microRNAs and their targets in different organs of Camellia sinensis var. assamica

To comprehensively annotate miRNAs and their targets in tea plant, Camellia sinensis, we sequenced small and messenger RNAs of 9 samples of Camellia sinensis var. assamica (YK-10), a diploid elite cultivar widely grown in southwest China. In order to identify targets of miRNAs, we sequenced two degradome sequencing profiles from leaves and roots of YK-10, respectively. By analyzing the small RNA-Seq profiles, we newly identified 137 conserved miRNAs and 23 species specific miRNAs in the genome of YK-10, which significantly improved the annotation of miRNAs in tea plant. Approximately 2000 differently expressed genes were identified when comparing RNA-Seq profiles of any two of the three organs selected in the study. Totally, more than 5000 targets of conserved miRNAs were identified in the two degradome profiles. Furthermore, our results suggest that a few miRNAs play roles in the biosynthesis pathways of theanine, caffeine and flavonoid. These results enhance our understanding of small RNA guided gene regulations in different organs of tea plant.