Phosphorus solubilizing microorganisms: mechanism and diversity

Abstract

Phosphorus (p) is the second important nutrient after nitrogen. Plants acquire P from soil solution as phosphate anion. P is the least mobile element in plant and soil contrary to other macronutrients. An adequate supply of P is required for proper functioning and various metabolic activities like photosynthesis, nitrogen fixation, proteins and nucleic acid production ete. Majority of P is fixed in soil and therefore plant available P is scarcely available despite the abundance of both organic and inorganic forms in soil. only 0.1% of the total P is available to plants because of its fixation and poor solubility In soil.P fixes with other metallic elements in the soil such as Ca, Al, Fe to form calcium phosphate, aluminium phosphate and ferrous phosphate and thus becomes unavailable to plants. The use of chemical fertilizers has long term effect on environment in terms of soil fertility depletion, eutrophication; this attitude forced us to find a sustainable way for efficient P availability in agriculture to meet the overgrowing demand of food. The use of phosphorus solubilizing microorganisms (PSM) opens a new way for better crop productivity and greater yield performance without affecting soil health. Some of the microorganisms such as Pseudomonas sp, Bacillus sp, Aspergillus and Pencillium strains have been identified as P solubilizers. The present review focuses on the phosphate plant interaction, mechanism of phosphorus solubilization.