Current Perspectives on Phosphate-Solubilizing Endophytic Fungi: Ecological Significances and Biotechnological Applications

Phosphorus is one of the essential nutrients for optimum plant growth after nitrogen. Their structural and chemical complexity greatly reduces their availability to the plants and is one of the major limiting macroelements to plant growth. Phosphorus is present in both organic and inorganic forms. Though abundant amount of phosphorus is present in the soil, its availability is reduced by various environmental factors that influence bio-geo-cycling of phosphorus. Current research is mainly focused on the exploitation of endophytic fungi for solubilization of phosphorus in an efficient way. Endophytic fungi including the genera Aspergillus, Penicillium, Piriformospora, Trichoderma, Curvularia, and other class of endophytic symbionts such as AM fungi are identified as potent Phosphate solubilizers. Endophytic fungi promote plant growth by a variety of mechanisms such as solubilization of “P”-like macronutrients by different reactions, able to produce bio-control agents, i.e., antibiotics and siderophores and plant protecting agents against pathogens, synthesis of growth hormones such as gibberellins, cytokines, and auxins. Phosphate-solubilizing endophytic fungi are promising and efficient organisms capable of increasing “P” availability and the best alternative approach to chemical fertilizers.