Systemic Signaling in the Maintenance of Phosphate Homeostasis

Abstract

Inorganic phosphate (Pi) availability in soils is often low and heterogeneous. Therefore, plants have evolved numerous adaptations to maintain Pi homeostasis that are regulated by both local and systemic signaling pathways. The level of sophistication in Pi signaling is exemplified by the presence of a key systemic signaling circuit that has been elucidated in the past decade. This circuit appears conserved among angiosperms and involves a phloem-mobile microRNA that targets a root-specific E2 conjugase. Recent advances regarding this circuit and its regulators, as well as additional systemic signaling factors, are the focus of this chapter.