Medicinal Plant Research 2025, Vol.15, No.5, 197-205 http://hortherbpublisher.com/index.php/mpr 199 Figure 1 Correlation between physiological indicators and ginsenosides. * Significant at p≤0.05, ** significant at p≤0.01 (Adopted from Di et al., 2023) 3.2 Precursor pathways of monosaccharide activation and polysaccharide synthesis Biosynthesis of ginseng polysaccharides proceeds with the activation of monosaccharides through metabolic pathways that yield nucleotide sugars (e.g., UDP-glucose, GDP-mannose). Key enzymes such as phosphoglucomutase (PGM), glucose-6-phosphate isomerase (GPI), UTP-glucose-1-phosphate uridylyltransferase (UGP2), fructokinase (scrK), mannose-1-phosphate guanylyltransferase (GMPP), phosphomannomutase (PMM), and UDP-glucose 4-epimerase (GALE) are integral to these processes. These enzymes catalyze the conversion of primary metabolites to activated sugar donors required to synthesize polysaccharides (Fang et al., 2022). 3.3 Roles of polysaccharide synthases and glycosyltransferases in biosynthesis Polysaccharide synthases and glycosyltransferases catalyze the modification and polymerization of the sugar residues, determining the final structure and function of ginseng polysaccharides. Transcriptome analysis identified 19 candidate enzymes in the synthesis of polysaccharides among which 17 were highly correlated with polysaccharide content. The genes encoding these enzymes are regulated by transcription factors such as MYB, AP2/ERF, bZIP, and NAC that combine the biosynthetic machinery in response to developmental and environmental cues (Fang et al., 2022). 3.4 Relationship between polysaccharide biosynthesis, cell wall metabolism, and storage substances Ginseng polysaccharide biosynthesis is closely associated with cell wall metabolism since the majority of polysaccharides are structural materials or reserve substances. Roots have the highest proportion of
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