miRNA Analysis of Leaves of Zijuan Tea (Camellia sinensis) Based on High throughput Sequencing

“Zijuan” is specific tea resource with abundant secondary metabolites, like catechins, anthocyanins, flavonoids, etc. Its biosynthesis is a network of multiple metabolic pathways connected by associated nodes, which is controlled by a variety of structural and regulatory genes. MicroRNAs (miRNAs), as a non-coding RNAs, play important roles in plant growth, development and secondary metabolism by regulating gene expression. In this study, four independent miRNA libraries of bud, second-leaf, open surface leaf and mature-leaf of “Zijuan” tea were constructed and sequenced by high-throughput sequencing. 126 known miRNAs were identified and divided into 26 families, and 119 novel miRNAs were predicted. Based on the transcriptome data of “Zijuan” tea, 724 and 2,285 target genes were predicted for known and novel miRNAs, respectively. The predicted target genes were mostly transcription factors, which included MYB and bHLH transcription factors for regulating the biosynthesis of secondary metabolites -- anthocyanins and flavonoids. All the above results would provide a theoretical basis for further studies on miRNA regulating the development of tea leaf and the biosynthesis of secondary metabolites in Camellia sinensis .