Phosphorus-solubilizing microorganisms: Advances in nutrient uptake mechanisms, plant growth promotion, and...

Phosphorus (P) is a primary mineral nutrient essential for the growth and productivity of many crop plants. Although abundant in nature, its bioavailability is limited due to the prevalence of insoluble forms. An alternative for meeting agricultural P demand is the application of P-solubilizing microorganisms (PSMs), which mobilize it. Although progress has been made in the study of PSMs, knowledge gaps still exist regarding their role in sustainable agriculture. Therefore, this review examines the barriers to P acquisition in low-solubility soils and highlights recent advances in understanding the mechanisms of P solubilization mediated by plant-associated bacteria and fungi. The molecular strategies involved in the uptake and transport of P from soil in plants are also analyzed. Bacteria from genera such as Bacillus, Pseudomonas, and Streptomyces, as well as fungi including arbuscular mycorrhizal fungi, Aspergillus spp., and Penicillium spp., employ various approaches to solubilize P, leading to improved plant nutrition. These mechanisms, which include the production of organic acids, cation chelation, proton exudation, and phosphatase activity, can be inferred from experimental approaches or genome mining strategies. The role of PSMs as plant growth promoters and enhancers of plant nutrition across diverse environmental conditions are also discussed. Finally, we propose the integration of PSM consortia as multifunctional bioinoculants to promote sustainable agricultural practices.