Phosphorus-Solubilizing Microbes and Their Potential in Sustainable Agricultural Production

Phosphorus (P) is the second most essential macronutrient which plays crucial role in growth and development of plants. Plants acquire this macronutrient in the form of phosphate anions. Despite the substantial quantity observed in inorganic and organic forms as it is generally in inaccessible for plant utility due to bond formation with other ions present in soil and also due to indiscriminate application of agrochemicals the environmental issues have reached on its peak. This has increased the interests of scientific community to find the sustainable alternative of these agrochemicals. Application of formulations of phosphorus solubilizers known as phosphorus-solubilizing microorganisms (PSM) are potential tool to increase plant health and yield. Diverse microbes like Rhizobium spp., Azotobacter sp., Bacillus sp., Serratia sp., Micrococcus spp., Pseudomonas spp., Azotobacter spp., Stenotrophomonas spp., Acinetobacter spp., Agrobacterium spp., Penicillium spp., Rhizopus spp., Fusarium spp., Aspergillus spp., Trichoderma spp, and various actinomycetes have been isolated and screened as phosphate-solubilizing microbes. The PSMs also act as biopesticides or biological control agents and help to withstand the extreme stress circumstances (like heavy metal toxicity) by producing ACC deaminase. With advent of time, organic farming is gaining attention as this technology is highly eco-friendly, so utilization of potential microbes for solubilization of phosphorus will improve plant health and crop quality. Additionally, the PSMs also produce various plant growth promoting substances which include indole acetic acid, cytokinins, gibberellin, acid and siderophores. This chapter provides in-depth knowledge about phosphorus-solubilizing microorganisms (PSM).