Fig. 1.

Schematic representation of the adaptive response of plants under P-limited conditions. Plants undergo morpho-physiological, biochemical, and molecular changes to cope with the depleted Pi levels. Altered root system architecture and its interaction with different microbial species, such as fungi (including mycorrhizal association) and plant growth-promoting rhizobacteria, help in increasing Pi accessibility for root uptake in the soil. The release of organic acids, phosphatases, and ribonucleases also facilitates the hydrolysis of organic P to release Pi in the rhizosphere. Membrane phospholipids are converted into glycolipids to free Pi from organic P compounds. Enhanced sucrose mobilization from shoots to roots supporting the reprogramming of root system architecture, the secretory acid phosphatase activity, and the robust activation of sucrose-dependent Pi starvation-induced genes such as high-affinity Pi transporters and purple acid phosphatases jointly contribute to the plant adaptation to low P availability. AMF Arbuscular mycorrhizal fungi, APase acidic phosphatase, DAG Diacylglycerol, GDPD Glycerophosphodiester phosphodiesterase, G3P Glycerol-3-phosphate, GLs Glycerolipids, P Phosphorus, PA Phosphatidic acid, PAPs Purple acid phosphatases, PC Phosphatidylcholine, PE Phosphatidylethanolamine, PHR Phosphate starvation response, PHTs Phosphate transporters, Pi Inorganic phosphate, PI Phosphatidylinositol, PLA Phospholipase A, PLs Phospholipids, Po Organic P, PM Plasma membrane, PPi Pyrophosphate, PSI Phosphate starvation-induced, MGDG Monogalactosyl-diacylglycerol, SPX; SYG1, PHO81, and Xpr1, SQDG Sulfoquinovosyl-diacylglycerol