Specialized structures and developmental mechanisms of secondary metabolite-synthesizing organs and tissues in medicinal plants.

Specialized structures in medicinal plants underpin the spatial regulation of secondary metabolism, determining the biosynthesis, accumulation, and storage of pharmacologically active compounds. Specialized structures, such as glandular trichomes, roots, rhizomes, laticifer, heartwood, and so on, have evolved distinct developmental programs and metabolic regulatory networks, enabling efficient synthesis, storage, and secretion of bioactive compounds. Understanding how these tissues originate, differentiate, and coordinate metabolism is essential not only for elucidating the molecular basis of plant chemical diversity but also for decoding the biosynthetic pathways of active ingredients and improving their yields through metabolic engineering. This study summarizes recent advances in elucidating the developmental and regulatory mechanisms underlying the formation and function of specialized structures in medicinal plants, including genetic, hormonal, and environmental controls. Moreover, it also highlights the technologies that have advanced the exploration of tissue-specific metabolism, development, and differentiation mechanisms. Together, this review summarizes recent progress in elucidating the types of specialized structures responsible for active compound biosynthesis and the underlying developmental mechanisms in medicinal plants, offering new perspectives for precision breeding and metabolic engineering of medicinal plants.