Phosphorus deficiency in plants: Responses, adaptive mechanisms, and signaling

Phosphorus (P) deficiency is a common nutritional factor limiting agricultural production around the globe. Application of phosphatic fertilizers is generally recommended to cope with P deficiency; however, low use efficiency of available P fertilizers both in calcareous and acid soils limits its viability and also had serious environmental concerns. Higher plants have adapted a number of mechanism to live with low available P in soil such as changes in root morphology and architecture, decreased growth rate, improved P uptake and utilization efficiency, and exudation of organic acids and enzymes to solubilize external inorganic and organic P compounds in the rhizosphere. Plant species and even cultivars widely differ in P efficiency because of differences in one or more of these mechanisms. Exploitation of these genetic variations among crop plants can sustain agricultural production. Understanding the mechanism involved in sensing P deficiency could facilitate selection, breeding, and genetic engineering approaches to improve crop production in P-stressed environments and could reduce dependence on nonrenewable inorganic P resources. In this chapter, we briefly reviewed the responses of P deficiency in higher plants, their adaptive mechanisms, and signaling pathways.