Study of tricalcium phosphate solubilization by some soil microfungi and evaluation of their potential as efficient plant growth-promoting organisms for Glycine max

The potential of use of fungi and bacteria as biological fertilizers is widely recognized and represents a key strategy to improve the phosphorous (P) availability for crops. P is both mobilized and sequestered in soil by the interaction of biological and geochemical processes. Exchangeable P represents a short-term storage pool that can replenish the soil solution. The aims of this research were to study P solubilisation mechanisms of some selected fungal strains with different life strategies and to evaluate their potential to promote efficiently soy growth. Saprotrophic fungi play very important geoactive roles in P biogeochemical cycle, for instance by leaching minerals and solubilizing insoluble P with different mechanisms in soils. The soybean is one of the most important plant for food production worldwide. P depletion is one of the most relevant abiotic constraints that threaten soybean production. Chemical analyses with SEM/EDXA, colorimetric quantification and ICP-MS were performed to quantify TCP solubilised by fungi in liquid medium and P concentration in fungal biomass (1–6). Tested fungi were able to solubilise tricalcium phosphate (TCP) in different extents, increasing P concentration in liquid medium and in biomass. Evaluation of soy growth promotion ability and fungal-plant interactions were studied by microscopy and histological evaluation of seedlings.