Medicinal Plant Research 2025, Vol.15, No.5, 206-213 http://hortherbpublisher.com/index.php/mpr 210 investigation on some of the MYB, bHLH, or WRKY factors in L. While functional studies in M. japonicus are in their infancy, the families play a part in the regulation of metabolic gene expression, as indicated by coordinated biosynthetic gene expression and amplification of gene clusters for specialized metabolism (Li et al., 2023; Wang et al., 2024). In addition, the MAPK signal pathway, being transcription factor-controllable, was discovered to regulate the expression of genes involved in estrogen biosynthesis and other metabolism (Du et al., 2020; Shi et al., 2024). 5.2 Signal regulation by plant hormones and environmental factors Plant hormones and the environment influence L. japonicus metabolic pathways tremendously. For example, MAPK and PI3K/AKT/NF-κB signaling pathways are involved in the modulation of estrogen biosynthesis, anti-inflammation reactions, and even wound healing, generally under hormonal or environmental stimuli (Shi et al., 2022; Ou et al., 2025). Chemical entities like luteolin and analogs influence such pathways, regulating the expression of such major metabolic enzymes and mediators. In addition, environmental stresses such as pathogen infection or oxidative stress trigger signal cascades that alter the accumulation of secondary metabolites, the sources of plant adaptability and medicinal value (Park et al., 2022; He et al., 2024). 5.3 Influence of epigenetics New findings show that epigenetic processes—DNA methylation, histone modification, and non-coding RNAs—are engaged in gene expression and metabolite accumulation regulation in medicinal plants. For L. japonicus, microRNA (miR-19a-3p) regulated apoptosis-related pathways, which influenced the anti-cancer activity of the plant through PTEN/PI3K/AKT pathway modulation (Park et al., 2022). Immediate research regarding DNA methylation and histone modification for L. is unavailable. When japonicus are not available, these mechanisms are likely to be involved in the dynamic regulation of biosynthetic gene clusters and tissue-specific bioactive compound accumulation, as observed in other medicinal crops. 6 Prospects of Synthetic Biology and Metabolic Engineering Applications 6.1 Construction and optimization of microbial heterologous expression platforms Identification of biosynthetic key genes (e.g., ADC, UGT, and SCPL for leonurine) makes reconstruction of plant metabolic pathways in microbial hosts possible. Large-scale production and functional validation of plant metabolites are possible through heterologous expression in bacteria or yeast. The use of strong microbial chassis, platform vector modularity, and genetically encoded biosensors also enhances the efficiency and precision of these platforms to produce valuable compounds in extranatural plant environments (Calero and Nikel, 2018; Li et al., 2023; Yu et al., 2023). 6.2 Application of gene editing technologies in functional gene validation and metabolic improvement CRISPR/Cas9 and other gene editing technologies are more and more being employed to validate gene function and modulate metabolic pathways. The technologies enable efficient management of biosynthetic genes, pathway regulators, and gene clusters in microbial platforms as well as even in L. japonicus itself. Multigene editing and synthetic gene circuits allow coordinated regulation of complex pathways, promoting yield and enabling the synthesis of new derivatives (Lee et al., 2018; Zhu et al., 2019; Lv et al., 2022; Kwan et al., 2023). 6.3 Pathway optimization and strategies for efficient biosynthesis Pathway optimization is to equilibrate gene expression, enzyme activity, and metabolic flux. Strategies include promoter engineering, enzyme engineering, dynamic regulation, and computational modeling for pathway performance prediction and optimization. Multigene stacking and assembly module systems can allow flexible reconstruction and fine-tuning of entire biosynthetic networks to optimize the yields of target metabolites (Zhu et al., 2019; Li et al., 2022; Lv et al., 2022; Kwan et al., 2023). 6.4 Challenges and opportunities in industrial development The main challenges include pathway elucidation incompleteness, host cell metabolic burden, and scalable, efficient production systems needed. The opportunities are the exploration of systems metabolic engineering, integration of omics data, and development of new microbial chassis for industrial bioproduction. Future advances
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