P_i sensing and signalling: from prokaryotic to eukaryotic cells

Phosphorus is one of the most important macronutrients and is indispensable for all organisms as a critical structural component as well as participating in intracellular signalling and energy metabolism. Sensing and signalling of phosphate (P_i) has been extensively studied and is well understood in single-cellular organisms like bacteria (Escherichia coli) and Saccharomyces cerevisiae. In comparison, the mechanism of P_i regulation in plants is less well understood despite recent advances in this area. In most soils the available P_i limits crop yield, therefore a clearer understanding of the molecular basis underlying P_i sensing and signalling is of great importance for the development of plants with improved P_i use efficiency. This mini-review compares some of the main P_i regulation pathways in prokaryotic and eukaryotic cells and identifies similarities and differences among different organisms, as well as providing some insight into future research.