Transcriptomes Analysis Reveals the Regulatory Roles of Noncoding RNA in Tanshinones Synthesis Pathway of Salvia Miltiorrhiza

Abstract Background: Long noncoding RNAs (lncRNAs), circular RNAs (circRNAs), and microRNAs (miRNAs) have been shown to play fundamental roles in plant development. However, the information of these noncoding RNAs (ncRNAs) in Salvia miltiorrhiza remains largely unexplored. In this study, the expression pattern of ncRNAs in six tissues from the same strain of S. miltiorrhiza was analyzed to study the biological function of ncRNAs on active ingredients synthesis.Methods: Analysis of tanshinone content differences of two root simples was carried out on high-performance liquid chromatography (HPLC). RNA sequencing, GO and KEGG enrichment analysis were applied to analyzing the targets of diferentially expressed ncRNAs in different organs.Results: A total of 6,929 lncRNAs, 6,239 circRNAs, and 360 miRNAs were identified. Forty-eight lncRNAs, 70 miRNAs, and 26 circRNAs expressed differentially between red and white root tissues with significantly different tanshinone content. GO and KEGG pathway analysis of target genes of differently expressed ncRNAs indicated that some target genes are involved in the synthesis pathway of terpene, including diterpene and sesquiterpene. We also found many target genes related to secondary metabolites, including 2-C-Methyl-d-erythritol 2,4-cyclodiphosphate Synthase (SmMCS) and several CYP450s. Furthermore, most target genes may be related to the resistance of pathogens, such as receptor kinases, disease-resistant proteins, and pentatricopeptide repeat-containing proteins. Conclusions: The present study exhibited the tissue-specific expression patterns of ncRNAs preliminarily in S. miltiorrhiza, which may reflect that the formation of white root or red root is related to regulation by ncRNAs. It would provide a basis for further research about the regulation mechanism in the tanshinone synthesis process.