Bridging Metabolic Pathways: Coordinated Regulation of Isoprenoid and Phenylpropanoid Metabolism in Plants

Plants face the core challenge of balancing growth and defense through fine-tuned metabolic regulation, which hinges on the coordinated biosynthesis of specialized metabolites such as isoprenoids and phenylpropanoids. This review integrates current insights into the dynamic interplay between these pathways, highlighting their role as a unified adaptive response to abiotic stresses, including drought, light, salinity, heavy metals, nutrient deficiency, altitude, temperature extremes, and combined stressors. Their interaction establishes a context-dependent regulatory network, characterized by both synergistic and antagonistic effects, potentially driven by competition for the shared precursor phosphoenolpyruvate. This metabolic node demands dynamic resource allocation, inherently generating trade-offs that shape its complex regulatory relationship. Hierarchical transcriptional networks, involving specific of transcription factors families, further refine this cross-pathway communication. By integrating environmental and developmental cues, these networks fine-tune metabolic output to achieve coordinated physiological responses. The crosstalk between isoprenoid and phenylpropanoid pathways is a key regulatory node for metabolic plasticity, enabling plants to deploy robust, multi-layered defenses. Deciphering the systemic signals and regulatory hubs governing these pathways is critical for the rational engineering of resilient crops and the optimization of phytochemical production. Adopting a holistic view of plant metabolic networks is equally vital for addressing global challenges from climate adaptation to sustainable agriculture.