Factors affecting phosphate-solubilizing activity of microbes: Current status

Abstract

Phosphorous (P) plays an important role in regulating the vital metabolism and concomitantly the health of plants. The use of phosphate-solubilizing microorganisms (PSM) in P-deficient soils has been found effective in transforming insoluble P into soluble forms and, hence, enriching the soil P pool. The structure, composition, and physiological functions of soil dwellers depend, however, on the variable soil constituents and other environmental factors. Moreover, the establishment and performance of these microbes are affected severely by environmental stressors such as high temperature, pH, and salt, etc. prevalent in degraded ecosystems such as alkaline/saline soils. Therefore, any alteration in normal environmental factors leads to poor growth and survival of PSM. Also, PSM, when introduced exogenously into soil as inoculant, encounter a furious competition from the indigenous soil microflora. The success of the inoculants, therefore, depends on how quickly and efficiently such microbes overcome the stressful environmental variables. This chapter focuses on the effects of different factors on the overall functioning of the PSM, which is likely to help in developing environment-friendly bio-inoculants, especially for P acquisition by plants under environmentally challenged conditions.