Research progress in molecular mechanism of rice phosphorus uptake and translocation

Phosphorus (P) is one of the major elements in plants, which account for nearly 0.2% of plant dry weight. P is crucial for plant’s growth and development because it is a key component of many important biological macromolecules and involves in many physiological and biochemical processes in plants. During the long-term course of evolution, a set of molecular regulation mechanisms have been formed for the efficient uptake and utilization of phosphorus in plants. This article summarized the molecular mechanism of root phosphate (Pi) uptake from soil, the translocation/redistribution of Pi in shoot, and give a prospection for future research efforts in Pi uptake and translocation in rice. Rice plants absorb Pi from soil through root system, which mainly relies on the PHT1Pi transporter located on the plasma membrane. After Pi is taken up into the plant cells, it is translocated into vascular bundles through apoplast and symplastic nutrient transport pathways, then is uploaded into xylem by the PHO1 to deliver to the shoot. Pi can also be redistributed between different tissues and organs according to their own demands. During these processes, excess Pi will be stored in the vacuoles, maintaining the cellular Pi homeostasis. Nowadays, the molecular mechanism of Pi uptake by Pi transporters is relatively clear. However, there are few studies on the mechanism of Pi storage, distribution and remobilization in plants. Vacuoles, as the main Pi storage part, play important roles for Pi homeostasis in rice cells. The node is an important part for nutrient distribution, contributing to the Pi distribution in rice plant. However, only a few studies have been conducted on the mechanisms of Pi transporters located on the vacuole membrane and the node cells. Therefore, efforts should be focused on the identification and functional analysis of Pi transporters responsible for Pi storage, distribution and remobilization, which will provide new basis for breeding high Pi efficient rice varieties in future.