Strategies of organic phosphorus recycling by soil bacteria: acquisition, metabolism, and regulation.

Critical to meeting cellular phosphorus (P) demand, soil bacteria deploy a number of strategies to overcome limitation in inorganic P (P ) in soils. As a significant contributor to P recycling, soil bacteria secrete extracellular enzymes to degrade organic P (P ) in soils into the readily bioavailable P . In addition, several P compounds can be transported directly via specific transporters and subsequently enter intracellular metabolic pathways. In this review, we highlight the strategies that soil bacteria employ to recycle P from the soil environment. We discuss the diversity of extracellular phosphatases in soils, the selectivity of these enzymes towards various P biomolecules and the influence of the soil environmental conditions on the enzyme's activities. Moreover, we outline the intracellular metabolic pathways for P biosynthesis and transporter-assisted P and P uptake at different P availabilities. We further highlight the regulatory mechanisms that govern the production of phosphatases, the expression of P transporters and the key metabolic changes in P metabolism in response to environmental P availability. Due to the depletion of natural resources for P , we propose future studies needed to leverage bacteria-mediated P recycling from the large pools of P in soils or organic wastes to benefit agricultural productivity.