Abstract As a finite and non-renewable resource, phosphorus (P) is essential to all life and crucial for crop growth and food production. The boosted agricultural use and associated loss of P to the aquatic environment are increasing environmental pollution, harming ecosystems, and threatening future global food security. Thus, recovering and reusing P from water bodies is urgently needed to close the P cycle. As a natural, eco-friendly, and sustainable reclamation strategy, microalgae-based biological P recovery is considered a promising solution.
Summary Phosphorus (P) is an essential element for plant growth and development. Vacuoles play a fundamental role in the storage and remobilization of P in plants, while our understanding of the evolutionary mechanisms of creating and reusing P stores are limited. Besides, we also know very little about the coordination of intercellular P translocation, neither the inorganic phosphate (Pi) signaling nor the Pi transport patterns. Here we summarize recent advances in understanding the core elements involved in cellular and/or subcellular P homeostasis and signaling in unicellular green algae and multicellular land plants.
OsPHO1;2 exports excess Pi from endosperm to maintain proper levels of AGPase activity for starch biosynthesis During starch biosynthesis in developing endosperm, glucose-1-P and ATP are converted into ADP-glucose and inorganic pyrophosphate (PPi) by ADP-glucose pyrophosphorylase (AGPase). ADP-glucose is used for starch biosynthesis and PPi is hydrolyzed into Pi. The plasma membrane (PM)-localized OsPHO1;2 is expressed in the endosperm cells and exports excess Pi from the developing endosperm to maintain Pi homeostasis for proper levels of AGPase activity and starch biosynthesis.