Screening, evaluation and selection ofphosphate-solubilising fungi as potential biofertiliser

Phosphate-solubilising saprophytic fungi have a potential application in plant nutrition; therefore, the aim of this study was 1) to perform a screening and isolation of native phosphofungi from volcanic soils of southern Chile, 2) to select a liquid medium for the evaluation of these phosphofungi and 3) to test a selected phosphofungus as a biofertiliser in a volcanic soil.The phosphofungi were screened using Martin medium (rose bengal-streptomycin agar) with calcium phosphate (Ca 3 (PO 4 ) 2 ) or calcium phytate as the phosphorus source.Six promising strains (Penicillium sp., Penicillium albidum, Penicillium thomii, Penicillium restrictum, Penicillium frequentans and Gliocladium roseum) were evaluated in the liquid media of Agnihotri, Asea-Wakelin, Pikovskaya and Nahas.The soluble phosphorus, acid phosphatase activity, pH and fungal biomass were determined.In most soils, the greatest proportion of phosphofungi solubilised organic P. The Asea-Wakelin medium appears to be the medium of choice for the quantitative evaluation of phosphofungi isolated from the volcanic soils tested.Penicillium albidum was selected as a potential biofertiliser due to its capacity to solubilise both inorganic and organic P via its specific solubilising activity (64 mg P/g fungus), phosphatase secretion and enhancement of the growth and mineral nutrition of lettuce plants growing in a volcanic soil.