ABSTRACT
Inorganic phosphate (Pi) is a critical essential macronutrient for plant growth and productivity. Pi availability in the rhizosphere regulates several biological and physiological processes such as energy metabolism, signal transduction, anthocyanin accumulation, organic acid formation and secretion. Plant responses to low Pi depend on the Pi levels in the rhizosphere and cellular Pi content. Pi is essential for the growth and development of the plant, and plant performance depends on the available Pi in the soil. To cope with Pi deficiency, the plant produces organic acids, for example citrate and malate, and secretes them into the rhizosphere. It has been shown that the overexpression of the genes involved in malate and citrate biosynthesis, malate dehydrogenase and citrate synthase, enhance Pi acquisition and biomass by organic acid exudation. Pi uptake from soil and transport from root to shoot depend on phosphate transporters. The root-to-shoot ratio of biomass change is one of the characteristic features of nutrient deprivation.
