Plant Response to Stress: Biochemical Adaptations to Phosphate Deficiency

Phosphate (Pi) is an essential macronutrient that plays a central role in virtually all metabolic processes in plants, including photosynthesis and respiration. Despite its importance, Pi is one of the least available nutrients in many ecosystems, and is a frequent limiting factor for plant productivity. Although plentiful in the earth’s crust, soil Pi often exists in insoluble mineral forms that render it unavailable to plants. Agricultural Pi deficiency is alleviated by the massive application of Pi fertilizers, currently estimated to be about 40 million metric tons per year worldwide. However, the assimilation of Pi fertilizers by crops is quite inefficient, as a large proportion of applied Pi becomes immobile, or may runoff into and thereby pollute nearby surface waters. Moreover, the world’s reserves of rock Pi (mined for production of Pi fertilizers) are expected to be depleted within the next century. Thus, studies of the complex mechanisms whereby plants acclimate to nutritional Pi deficiency are of great importance. This could lead to the development of rational strategies for engineering Pi-efficient transgenic crops that would reduce or eliminate our current overreliance on expensive, polluting, and nonrenewable Pi fertilizers. The aim of this article is to provide a brief overview of the fascinating biochemical adaptations of Pistarved ( Pi) plants.