A tissue-specific profile of miRNAs and their targets related to paeoniaflorin and monoterpenoids biosynthesis in Paeonia lactiflora Pall. by transcriptome, small RNAs and degradome sequencing.

Paeonia lactiflora Pall. (Paeonia) has aroused many concerns due to its extensive medicinal value, in which monoterpene glucoside paeoniflorin and its derivatives are the active chemical components. However, little is known in the molecular mechanism of monoterpenoids biosynthesis, and the regulation network between small RNAs and mRNAs in monoterpenoids biosynthesis has not been investigated yet. Herein, we attempted to reveal the tissue-specific regulation network of miRNAs and their targets related to paeoniaflorin and monoterpenoids biosynthesis in Paeonia by combining mRNA and miRNA expression data with degradome analysis. In all, 289 miRNAs and 30177 unigenes were identified, of which nine miRNAs from seven miRNA families including miR396, miR393, miR835, miR1144, miR3638, miR5794 and miR9555 were verified as monoterpenoids biosynthesis-related miRNAs by degradome sequencing. Moreover, the co-expression network analysis showed that four monoterpenoids-regulating TFs, namely AP2, MYBC1, SPL12 and TCP2, were putatively regulated by five miRNAs including miR172, miR828, miR858, miR156 and miR319, respectively. The present study will improve our knowledge of the molecular mechanisms of the paeoniaflorin and monoterpenoids biosynthesis mediated by miRNA to a new level, and provide a valuable resource for further study on Paeonia.