Quantitative Estimation of Phosphate-Solubilizing Capacity in Fungal Endophytes of Saffron Corms

Abstract

Endophytic filamentous fungi from three genera, Trichoderma, Aspergillus and Penicillium, isolated from saffron corms, were tested in vitro for their ability to solubilize phosphorus from tricalcium phosphate and rock phosphate. When fungal strain filtrates were transferred into NBRIP medium amended with Ca3(PO4)2, Penicillium aeris showed the highest soluble phosphorus concentration, reaching 39.66 μg/ml after 5 days of incubation at 28°C, while the concentrations of soluble phosphorus in Trichoderma filtrates ranged from 18.33 to 29.4µg/ml, and those in Aspergillus filtrates ranged from 32,33 to 35,66µg/ml. The pH values decreased over time, reaching their lowest points of 3.38 and 3.57 after 196 hours of incubation in the culture filtrates of Aspergillus niger and Penicillium aeris, respectively. For rock phosphate solubilization, Trichoderma isolates, along with Aspergillus nomius, A. ochraceus, A. niger, Penicillium sp. and P. aeris, are among the most effective. This study highlights endophytic fungi's role in enhancing soil fertility and plant growth by solubilizing phosphates.