Medicinal Plant Research 2024, Vol.14, No.1, 31-44 http://hortherbpublisher.com/index.php/mpr 40 contained peroxidase enzyme exhibits significant anti-aging effects. Long-term consumption can eliminate facial scars and promote smooth and tender skin. It also serves as a raw material for synthesizing steroidal hormones and contraceptives. The biosynthesis of diosgenin saponins can be divided into three stages: the first stage involves the biosynthesis of upstream terpene skeletons, from which steroidal saponins derive. This pathway proceeds through the mevalonate (MVA) pathway, ultimately synthesizing isopentenyl pyrophosphate (IPP) and dimethylallyl pyrophosphate (DMAPP). Hydroxymethylglutaryl-CoA reductase (HMGCR) acts as a key enzyme catalyzing the rate-limiting step in terpene skeleton biosynthesis. Expression analysis of the HMGCR gene in Dioscorea nipponica roots induced by methyl jasmonate treatment revealed a positive response to methyl jasmonate stimulation. The second stage involves the biosynthesis of cholesterol, a precursor of diosgenin saponins. A crucial rate-limiting step in this stage is the catalysis of squalene to 2,3-oxidosqualene by squalene epoxidase (SE). The SE gene is critical during this phase, and its expression pattern induced by methyl jasmonate correlates highly with the expression patterns of genes involved in terpene skeleton synthesis. The third stage is the conversion of cholesterol into diosgenin saponins, which includes two important rate-limiting steps: the catalytic process of cholesterol to diosgenin saponin precursors involving P450, and the glycosyltransferase-mediated conversion of diosgenin saponin precursors to diosgenin saponins. Methyl jasmonate, phytosteroid hormones brassinosteroids and campesterol maintain a balance between plant growth, development, and defense mechanisms, representing an antagonistic relationship (Kim et al., 2013). A critical step in regulating phytosterol metabolism towards secondary metabolites derived from cholesterol or plant steroid hormones involves the catalysis process of C-24 methyltransferase (Diener et al., 2000; Holmberg et al., 2002). 6.3 Functional studies on bioactive compounds Functional studies on the bioactive compounds of Dioscorea species have highlighted the pharmacological potential of these plants. For example, the metabolome and transcriptome profiling of Dioscorea cirrhosa identified 531 metabolites, including 62 flavonoids, and revealed the regulatory network and mechanism of flavonoid biosynthesis, which is crucial for the plant's medicinal properties (Yan et al., 2022). Additionally, a narrative analysis on the pharmacological activities of various Dioscorea species, has compiled evidence of their anti-inflammatory, antimicrobial, anticancer, antioxidant, anti-diabetic, antihypertensive, and estrogenic effects (Jamaludin et al., 2023). These studies provide a scientific basis for the further development and utilization of yam as a medicinal plant. 7 Future Perspectives 7.1 Potential for genomic-driven breeding programs The genomic analysis of yam has opened new avenues for breeding programs aimed at improving desirable traits. For instance, the identification of genomic regions linked to sex determination and cross-compatibility in Dioscorea alatacan be leveraged to enhance hybridization success in breeding programs (Mondo et al., 2021). Additionally, the development of high-resolution DNA barcodes for Dioscorea species discrimination and phylogenetic analysis provides a robust framework for identifying and selecting superior genotypes (Xia et al., 2019). The comprehensive characterization of yam tuber nutrition and medicinal quality across different geographic groups further supports the potential for targeted breeding strategies to enhance both nutritional and medicinal properties (Shan et al., 2020). These genomic tools and insights will enable breeders to unlock the potential of Dioscoreaspecies, and take full advantage of its adaptability to varied environments (Bredeson et al., 2021). 7.2 Integrating genomic data with traditional knowledge Integrating genomic data with traditional knowledge of yam's medicinal properties can significantly enhance the understanding and utilization of this species. Traditional Chinese medicine has long recognized the benefits of yam, particularly its role in regulating spleen and stomach functions (Zhang et al., 2019). By combining this traditional knowledge with modern genomic insights, such as the identification of key pathways and hormone activities involved in microtuber formation (Li et al., 2020), researchers can develop more effective and targeted medicinal applications. Furthermore, the structural characterization of bioactive compounds, such as galactan from yam, and their effects on human gut microbiota, provides a scientific basis for the traditional uses of this
RkJQdWJsaXNoZXIy MjQ4ODYzNA==