Phosphate (Pi) is a critical nutrient for plants, but it is often scarce in soil. High-affinity Pi transporters in roots are key for Pi uptake. Plants adapt to Pi deficiency by enhancing Pi acquisition, uptake, and efficiency. This is regulated by transcription of high-affinity transporters, which are encoded by a few genes with specific tissue expression patterns. These genes are strongly induced during Pi deficiency, improving Pi acquisition. Plants also activate biochemical mechanisms to increase Pi uptake from inorganic and organic sources. Altered root morphology and mycorrhizal symbiosis further enhance Pi acquisition. Cellular Pi levels regulate these responses. Phosphate acquisition and utilization involve activation or inactivation of many genes. This review discusses molecular, biochemical, and physiological factors in Pi acquisition. Phosphorus is essential for energy metabolism, nucleic acids, and membranes. Pi activates processes like photosynthesis and respiration. Phosphate esters act as energy carriers, and phospholipids are important for membrane function. Phosphorylation is crucial for signal transduction. Phosphate homeostasis in chloroplasts regulates sugar transport and starch synthesis. Plants absorb Pi as anions from soil. Pi is scarce in the rhizosphere due to fixation and organic complex formation. Phosphorus deficiency limits crop production, especially in tropical regions. Plants enhance Pi acquisition under deficiency, regulated at the transcriptional level. Phosphate availability is a major factor in crop productivity. Pi levels in soil are much lower than in plant cells. Low Pi availability in the rhizosphere limits growth. Available Pi rarely exceeds 10 µM. In tropical and semi-arid soils, Pi deficiency is severe. Over 5.7 billion hectares are Pi-deficient. Acid soils fix more Pi, reducing plant availability. Organic and inorganic fixation may make 80% of applied Pi unavailable. Tropical regions, especially Africa, face nutrient depletion without fertilizers. Phosphate rock reserves may be depleted in 60-90 years. Increasing population and agriculture on low-fertility lands will increase phosphate fertilizer demand. Phosphate uptake is highly regulated. Plants must acquire Pi against a steep concentration gradient. Electrical gradients also influence uptake. Models explain Pi acquisition under deficiency and sufficiency. A dual uptake model involves high- and low-affinity mechanisms. Soil and plant factors influence Pi uptake. Genetic evidence shows transporters function at high and low Pi concentrations. Low-affinity transport is constitutive, while high-affinity is enhanced under Pi deficiency. Orthophosphate (H2PO4-) is preferred for transport. Low Pi levels in soil require high-affinity transporters. Pi is taken up via energy-mediated co-transport with protons. The transport process may be energized by symport of 2-4 H+ per H2PO4- ion.Phosphate (Pi) is a critical nutrient for plants, but it is often scarce in soil. High-affinity Pi transporters in roots are key for Pi uptake. Plants adapt to Pi deficiency by enhancing Pi acquisition, uptake, and efficiency. This is regulated by transcription of high-affinity transporters, which are encoded by a few genes with specific tissue expression patterns. These genes are strongly induced during Pi deficiency, improving Pi acquisition. Plants also activate biochemical mechanisms to increase Pi uptake from inorganic and organic sources. Altered root morphology and mycorrhizal symbiosis further enhance Pi acquisition. Cellular Pi levels regulate these responses. Phosphate acquisition and utilization involve activation or inactivation of many genes. This review discusses molecular, biochemical, and physiological factors in Pi acquisition. Phosphorus is essential for energy metabolism, nucleic acids, and membranes. Pi activates processes like photosynthesis and respiration. Phosphate esters act as energy carriers, and phospholipids are important for membrane function. Phosphorylation is crucial for signal transduction. Phosphate homeostasis in chloroplasts regulates sugar transport and starch synthesis. Plants absorb Pi as anions from soil. Pi is scarce in the rhizosphere due to fixation and organic complex formation. Phosphorus deficiency limits crop production, especially in tropical regions. Plants enhance Pi acquisition under deficiency, regulated at the transcriptional level. Phosphate availability is a major factor in crop productivity. Pi levels in soil are much lower than in plant cells. Low Pi availability in the rhizosphere limits growth. Available Pi rarely exceeds 10 µM. In tropical and semi-arid soils, Pi deficiency is severe. Over 5.7 billion hectares are Pi-deficient. Acid soils fix more Pi, reducing plant availability. Organic and inorganic fixation may make 80% of applied Pi unavailable. Tropical regions, especially Africa, face nutrient depletion without fertilizers. Phosphate rock reserves may be depleted in 60-90 years. Increasing population and agriculture on low-fertility lands will increase phosphate fertilizer demand. Phosphate uptake is highly regulated. Plants must acquire Pi against a steep concentration gradient. Electrical gradients also influence uptake. Models explain Pi acquisition under deficiency and sufficiency. A dual uptake model involves high- and low-affinity mechanisms. Soil and plant factors influence Pi uptake. Genetic evidence shows transporters function at high and low Pi concentrations. Low-affinity transport is constitutive, while high-affinity is enhanced under Pi deficiency. Orthophosphate (H2PO4-) is preferred for transport. Low Pi levels in soil require high-affinity transporters. Pi is taken up via energy-mediated co-transport with protons. The transport process may be energized by symport of 2-4 H+ per H2PO4- ion.