Identification of the Genome-Wide Expression Patterns of Non-Coding RNAs Associated with Tanshinones Synthesis Pathway in Salvia miltiorrhiza

The red root of Salvia miltiorrhiza Bunge, a famous traditional Chinese medicine (TCM), was caused by tanshinone in epidermis cells. In order to study the biological function of ncRNAs in the tanshinone synthesis, the expression patterns of mRNA and ncRNAs were comprehensively analyzed in red (high tanshinone content) and white root (low tanshinone content) tissues derived from the same plant. A total of 731 differentially expressed genes (DEGs) were mainly enriched in primary metabolic pathways such as galactose and nitrogen, and some secondary metabolic pathways such as phenylpropanoid and terpenoids. A total of 70 miRNAs, 48 lncRNAs, and 26 circRNAs were identified as differentially expressed (DE) ones. The enrichment pathway of the targets of DE-lncRNA were mainly in ribosome, carbon metabolism, plant hormone signal transduction, and glycerophospholipid metabolism. The function of the targets genes of 59 miRNAs combined with DE-circRNAs was mainly involved in plant-pathogen interaction, endocytosis, phenylpropanoid biosynthesis, and sesquiterpenoid and triterpenoid biosynthesis pathways. Most genes of the tanshinone synthesis pathway had a higher expression. Some ncRNAs were predicted to regulate several key enzyme genes of the tanshinone synthesis pathway, such as SmDXS2, SmGGPPS1, SmKSL. Furthermore, most target genes were related to the resistance of pathogens. The present study exhibited the tissue-specific expression patterns of ncRNAs, which would provide a basis for further research into the regulation mechanism of ncRNAs in the tanshinone synthesis process.