Regulation of low phosphate stress in plants

Abstract The deficiency of phosphorous (P) in the soil severely affects the worldwide crop production. Plants uptake P from the soil solutions in the form of inorganic phosphate (Pi) and respond to low Pi stress through morphological, physiological, and molecular changes that have been well documented over the last two decades. Low Pi stress inhibits the growth of primary root with the production of more lateral roots and root hairs for increased topsoil foraging of Pi. The Phosphate Transporter1 families of transporters, which are involved in the acquisition of Pi from soil, are induced under low Pi stress. Expression of other Pi transporters involved in the export of Pi into shoots and movement of Pi into intracellular organelles were also studied. Many other transcription factors play vital roles in the regulation of low Pi stress in plants. Several molecules, such as microRNAs, are also involved in long-distance signaling of low Pi stress responses. Hormones, lipids, and sugars also play key roles under low Pi-stress condition. Apart from these, exudation of organic acids is also considered as one of the important mechanisms of plants to improve the availability of Pi around rhizosphere. Several plants also establish symbiotic associations with arbuscular mycorrhizae fungi for enhanced uptake of Pi. All these details have been discussed in this chapter. Understanding and proper manipulation of low Pi stress responses will help to overcome the low Pi stress and enhance the P-use efficiency (PUE) in plants.