In vitro P - solubilization activity of halophilic fungi in salt - affected soils and their potential as bio - inoculants

Abstract

Some fungi have a unique ability to adapt and establish beneficial association with crop in salt–affected soils. Therefore, present study was conducted to characterize the salinity–tolerance, P–solubilization and growth promotion ability of the fungal isolates from the rhizosphere of salt–tolerant crops. The rhizospheric soil showed an assemblage of fifteen phosphate–solubilizing fungal (PSF) isolates tolerant to salinity (5% NaCl w/v), alkalinity (pH 8.0), and thermal stress (up to 40oC). Soil pH, EC, organic carbon, KMnO4–N, Olsen’s P, and NH4OAc–K explained about 51.6% variability in the rhizosphere assemblage of the microorganisms. The genera Aspergillus and Penicillium were abundant in rhizosphere. The association of Penicillium spp. with crops was greater in soil of higher salinity than Aspergillus. The salt–tolerant fungi demonstrated variable effects on the germination of different crops. Siderophore and fungal biomass of the isolates cause 23% variability in plant growth parameters. The PSF strains PP3 and SA1 of the Penicillium and Aspergillus, respectively, showed high P solubilization without any appreciable change at high salinity. This study concluded that the PSF producing siderophores and phytohormones has significant importance for promoting growth and survival of crops in salt–affected soils.