A Universal Gatekeeper Unloading Nutrients to Seeds

Seed formation is an important mechanism in plant evolution that serves as the material basis for human survival. After double fertilization, the development of both the embryo and the endosperm requires a large amount of nutrients, and long-distance sucrose transportation is indispensable. We recently discovered a ring-shaped structure that can affect the unloading of nutrients into seeds. This structure is formed by the deposition of callose, which blocks the transport of nutrients by reducing the pore size of the plasmodesmata (PD). If fertilization is successful, the PD gate will form, but will remain open; if fertilization fails, the PD gate will be gradually closed—a strategy that efficiently prevents energy loss. A similar gating mechanism exists in rice, indicating that this strategy has substantial potential for agricultural production.