Regulation of phosphate starvation responses in higher plants

†Background Phosphorus (P) is often a limiting mineral nutrient for plant growth. Many soils worldwide are deficient in soluble inorganic phosphate (Pi), the form of P most readily absorbed and utilized by plants. A network of elaborate developmental and biochemical adaptations has evolved in plants to enhance Pi acquisition and avoid starvation. †Scope Controlling the deployment of adaptations used by plants to avoid Pi starvation requires a sophisticated sensing and regulatory system that can integrate external and internal information regarding Pi availability. In this review, the current knowledge of the regulatory mechanisms that control Pi starvation responses and the local and long-distance signals that may trigger Pi starvation responses are discussed. Uncharacterized mutants that have Pirelated phenotypes and their potential to give us additional insights into regulatory pathways and Pi starvationinduced signalling are also highlighted and assessed. †Conclusions An impressive list of factors that regulate Pi starvation responses is now available, as is a good deal of knowledge regarding the local and long-distance signals that allow a plant to sense and respond to Pi availability. However, we are only beginning to understand how these factors and signals are integrated with one another in a regulatory web able to control the range of responses demonstrated by plants grown in low Pi environments. Much more knowledge is needed in this agronomically important area before real gains can be made in improving Pi acquisition in crop plants.