Organellar transporters in regulating metal long-distance transport in plants and the potential for crop improvement

• Organellar transporters coordinate metal intracellular and long-distance transport. • Organelle compartmentalization regulates long-distance metal transport. • Vesicles and plasmodesmata are involved in long-distance metal transport. • Organellar transporters can be used for mineral biofortification in crops. Long-distance transport of metal micronutrients across plant tissues is essential for optimal growth and development. Organellar transporters serve as central regulators of intracellular metal homeostasis, and are also increasingly recognized as critical contributors to systemic metal distribution within plant. Yet, their involvement in long-distance transport remains underrepresented in current conceptual framework of plant metal physiology. In this review, we synthesize the advances in understanding how organellar transporters govern intracellular metal homeostasis. Next, we focus on their regulatory roles in long-distance metal transport and propose a mechanistic framework comprising three pathways, in which organellar transporters regulate long-distance transport by modulating the compartmentalization of metals in organelles, the vesicle-mediated metal trafficking, and symplastic metal movement via ER-plasmodesmata continuity. Furthermore, we evaluate the current applications and future prospects of targeting organellar transporters to enhance micronutrient biofortification and mitigate heavy metal accumulation in crops. Our analysis clarifies the framework for organellar transporter–mediated long-distance metal transport and facilitates the understanding of how metal homeostasis is coordinately regulated across subcellular, cellular, and tissue scales, thereby bridging fundamental insights with translational strategies for crop improvement.