Rhizobacterial Phosphate Solubilizers in Sustainable Agriculture: Concepts and Prospects

Abstract

Phosphorous is the second most important macroelement in plant nutrition. The availability of the P present in the soil and being applied through chemical fertilizers is very poor due to fixation in acid and alkaline soils and occurs in insoluble state. Soil microorganisms play a central role in biogeochemical cycling of P in soil which converts unavailable form to available form and enables plant for the uptake. Rhizobacterial strains Bacillus sp. and Pseudomonas sp. and soil fungi Aspergillus sp. and Penicillium sp. are the key representatives of potential phosphate-solubilizing microbes. Solubilization of P is a complex process which depends on physiological and nutritional attributes of the strain. Organic acid production is the principal mechanism of solubilization carried out by majority of documented phosphate-solubilizing microorganisms (PSM). Besides inorganic acids, siderophores and phosphatases mediate solubilization. In the current scenario, genetic manipulation of the strain to improve P solubilization efficacy is a promising strategy. PSM have also been reported to enhance the plant growth through the production of growth-promoting substances and phytohormones. Moreover, the development of consortia of PSM with other beneficial microflora having multiple benefits would attract the farming community and helps in making the agriculture production system more sustainable. PU - SPRINGER-VERLAG SINGAPORE PTE LTD PI - SINGAPORE PA - 152 BEACH ROAD, #21-01/04 GATEWAY EAST, SINGAPORE, 189721, SINGAPORE