Phosphate: the Silent Challenge

Abstract

Phosphorus (P) is one of the most vital elements for all living organisms which acts as a<br />constituent of essential biomolecules such as nucleic acids, phospholipids, and phosphosugars,<br />and as a major contributor to almost all metabolic reactions including photosynthesis,<br />respiration, and energy delivery. It is one of the most needed nutrients for plant growth and<br />development. Despite high levels of P in the soil, plants absorb it only in the soluble inorganic<br />form of free phosphate ion (Pi) which is scarce in soil. Therefore, there has been a large demand<br />for Pi fertilizers to secure crop yields, yet its deposition in soil and gradual run-off into water<br />reservoirs lead to chains of events that cause irreversible damages to ecosystems. Researches,<br />including genome-wide data analyses, have revealed interesting molecular aspects of plant<br />adaptive strategies to deal with low Pi concentrations in soil. These include the higher<br />expression of acid phosphatases and Pi transporters as well as the secretion of organic acids in<br />the rhizosphere that maintain cellular Pi homeostasis in order to keep metabolic reactions<br />running. Describing the cycle of Pi exchange between physical and biological worlds, the extent<br />to which current agricultural practices are disturbing the cycle, the necessity of introducing lessdestructive<br />methods of providing Pi, and alternative measures and solutions for sustainable<br />agriculture will be discussed in this review.