Medicinal Plant Research 2025, Vol.15, No.5, 197-205 http://hortherbpublisher.com/index.php/mpr 200 polysaccharides and their monosaccharide compositions, which reflects storage and structural roles. Polysaccharide biosynthesis is regulated dynamically to facilitate cell wall building and reserve carbohydrate deposition, thus enhancing plant growth, stress tolerance, and medicinal property (Guo et al., 2020). 4 Regulatory Mechanisms of Ginsenoside and Polysaccharide Biosynthesis 4.1 Roles of transcription factors in ginsenoside and polysaccharide biosynthesis Transcription factors (TFs) such as bHLH, WRKY, MYB, NAC, and GRAS are central regulators of ginsenoside and polysaccharide biosynthesis in Panax ginseng. For ginsenosides, bHLH, WRKY, MYB, and ERF TFs have been shown to directly regulate the expression of important biosynthetic genes such as those encoding cytochrome P450s and glycosyltransferases (Wei et al., 2024). For example, PgWRKY4X activates the transcription of squalene epoxidase to promote ginsenoside accumulation (Yao et al., 2020), and PgNAC72 responds to methyl jasmonate (MeJA) and regulates saponin biosynthesis by upregulating dammarenediol synthase (Jiang et al., 2024). GRAS TFs, for example, PgGRAS68-01, also modulate ginsenoside biosynthesis through spatiotemporal gene expression (Liu et al., 2023). In polysaccharide biosynthesis, MYB, AP2/ERF, bZIP, and NAC TFs are linked to the expression of key enzymes involved in sugar metabolism and polymerization, indicating their regulation on polysaccharide structure and content (Fang et al., 2022; Hou et al., 2022) (Figure 2). Figure 2 Ginsenoside biosynthesis pathway (A) and saponin skeleton biosynthesis gene expression pattern (B) (Adopted from Hou et al., 2022) 4.2 Influence of signal transduction pathways Environmental stresses, exogenous elicitors, and hormone signals are highly important for ginsenoside and polysaccharide biosynthesis. Methyl jasmonate (MeJA) is a potent elicitor, inducing TFs like NAC and MYB and initiating gene activation in the ginsenoside pathway (Zhang et al., 2021; Jiang et al., 2024). Sucrose is a metabolic signal, inducing ginsenoside biosynthesis by promoting glycolysis and the mevalonate pathway, particularly by activating HMGR (Rui et al., 2022). Environmental elicitors such as fungal elicitors (e.g., Chaetomium globosum) and cerium ions also enhance ginsenoside accumulation by initiating ROS signaling and endogenous MeJA biosynthesis (Yao et al., 2020; Zhang et al., 2021). WRKY TFs also respond to various abiotic stresses (heat, cold, drought), associating stress adaptation with the generation of secondary metabolites (Di et al.,
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