Phosphorus Deficiency in Plants: Responses, Adaptive Mechanisms, and Signaling

Abstract

Phosphorus (P) defi ciency is a common nutritional factor limiting agricultural production around the globe. Application of phosphatic fertilizers is generally recommended to cope with P defi ciency; 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 effi ciency, 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 effi ciency 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 defi ciency 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 briefl y reviewed the responses of P defi ciency in higher plants, their adaptive mechanisms, and signaling pathways.

Strigolactones Control Root System Architecture and Tip Anatomy in Solanum lycopersicum L. Plants under P Starvation

“…Root hair development is under hormonal control [48] and increasing the amount of root hairs is a common strategy adopted by P-deprived plants to enhance the capacity of their roots to explore the rhizosphere for P scavenging [16,49]. A strigolactone-auxin crosstalk has been proposed to regulate root hair formation and elongation, with strigolactones triggering the increase in auxin accumulation in root epidermal cells through modulation of auxin flux from the root [9,26,39,50].…”

“…Phosphorus is one of the essential macronutrients required by plants for their growth and development [15], being a structural component of key biomolecules [16,17] and taking part in primary cellular metabolic processes [15,18,19]. Therefore, whole-plant growth is substantially reduced or inhibited by P limitation [2].…”

“…It is noteworthy that P deficiency represents one of the major restraints in agricultural production, as P in soil is one of the most immobile, inaccessible, and unavailable among all nutrient elements [17,20]. Phosphorus is absorbed and assimilated by plants as phosphate (Pi), which occurs at fairly low concentrations in the soil solution, typically in the 1-10 µM range [16,[21][22][23]. This is because Pi tends to establish strong interactions with soil colloids (mainly Fe and Al oxides), on which it can be almost irreversibly adsorbed or occluded [24].…”

Nanophosphorus Fertilizer Stimulates Growth and Photosynthetic Activity and Improves P Status in Rice

“…In contrast, research on macronutrients is limited, although these elements drive global crop production [8]. Among macronutrients, phosphorus (P) deficiency is a common factor hindering yield and crop quality worldwide [9].…”

The Response of Maize to Inoculation with Arthrobacter sp. and Bacillus sp. in Phosphorus-Deficient, Salinity-Affected Soil

“…The growth of the shoot was more markedly compromised by P deficiency than by salinity stress, as would have been predicted, given that shoot growth is generally more sensitive to nutrient deficiency (including not just P, but also nitrogen and iron) than to salinity [ 21 , 24 ]. The observed boost to root elongation in each of the four maize varieties induced by P deficiency mirrors the response to this stress of rice plants [ 25 ], reflecting an adaptive response in which the P uptake is enhanced by expanding the surface area of the root system [ 25 , 26 ].…”