Analysis of the miRNA Transcriptome in Aconitum vilmorinianum and Its Regulation of Diterpenoid Alkaloid Biosynthesis

Aconitum vilmorinianum (A. vilmorinianum) is an important medicinal plant in the Aconitum genus that is known for its diterpenoid alkaloids, which exhibit significant pharmacological activity and toxicity, thus making it valuable for both medicinal use and as a biopesticide. Although the biosynthesis of terpenoids is well characterized, the potential gene regulatory role of microRNAs (miRNAs) in terpenoid biosynthesis in A. vilmorinianum remains unclear, and further research is needed to explore this aspect in this species. In this study, miRNA sequencing was conducted to analyze the miRNA population and its targets in A. vilmorinianum. A total of 22,435 small RNAs were identified across the nine samples. Through miRNA target gene association analysis, 356 target genes from 54 known miRNAs and 977 target genes from 151 novel miRNAs were identified. Target identification revealed that miR6300 targets the hydroxymethylglutaryl-CoA reductase (HMGR) gene, which is involved in the formation of the terpenoid backbone and regulates the synthesis of diterpenoid alkaloids. Additionally, preliminary findings suggest that miR4995 and miR5021 may be involved in the regulation of terpenoid biosynthesis, although further biochemical analysis is needed to confirm these potential roles. This study provides a foundational understanding of the molecular mechanisms by which miRNAs regulate terpenoid biosynthesis in A. vilmorinianum and offers scientific evidence for further research on the biosynthesis of diterpenoid alkaloids in this medicinal plant.