Auxin-Mediated Regulation of Tanshinone Biosynthesis in Salvia miltiorrhiza: Insights from Transcriptomic Analysis

Salvia miltiorrhiza is a medicinal plant known for producing tanshinones, bioactive diterpenoids that mainly accumulate in the periderm of mature roots. Their biosynthesis involves a multi-step pathway, with the third phase still poorly understood. To clarify the regulatory role of indole-۳-acetic acid (IAA) and N-۱-naphthylphthalamic acid (NPA), transcriptomic analysis was conducted. A total of ۱,۲۰۲ differentially expressed genes (DEGs) were identified, including ۴۶۱ upregulated and ۷۴۱ downregulated genes, indicating overall suppression by hormonal treatments. GO and KEGG enrichment analyses showed that upregulated DEGs were significantly involved in terpenoid biosynthesis, notably the diterpenoid biosynthesis pathway (KEGG: smil۰۰۹۰۴), essential for tanshinone production. Key upregulated genes such as CPSI, ferruginol synthase-like, and sugiol synthase suggest that auxin promotes tanshinone biosynthesis by enhancing critical steps in diterpenoid metabolism. Downregulated genes were associated with lignin biosynthesis, oxidative stress responses, and transcription factor activity, reflecting a shift from structural defense to secondary metabolism. Notably, IAA markedly induced several cytochrome P۴۵۰ genes involved in tanshinone diversification, while NPA had minimal effect. These results highlight the central role of auxin signaling rather than root architecture in regulating tanshinone biosynthesis. This study offers insights into hormone-mediated regulation of secondary metabolism in S. miltiorrhiza and identifies candidate genes for future metabolic engineering

کلیدواژه ها:

Indole-۳-acetic acid ، N-۱-naphthylphthalamic acid ، Salvia miltiorrhiza ، Tanshinone ، Transcriptome