Abstract Intracellular inorganic orthophosphate (Pi) distribution and homeostasis profoundly affect plant growth and development. However, its distribution patterns remain elusive owing to the lack of efficient cellular Pi imaging methods. Here we develop a rapid colorimetric Pi imaging method, inorganic orthophosphate staining assay (IOSA), that can semi-quantitatively image intracellular Pi with high resolution. We used IOSA to reveal the alteration of cellular Pi distribution caused by Pi starvation or mutations that alter Pi homeostasis in two model plants, rice and Arabidopsis, and found that xylem parenchyma cells and basal node sieve tube element cells play a critical role in Pi homeostasis in rice.
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.
