Screening and Identification of the Rhizosphere Fungal Communities Associated with Land Reclamation in Egypt

Soil fungi are a wide range of microorganisms that play an essential role in enhancing the available nutrients in the soil for plants. In the current study, to study the fungal association with newly reclaimed land in Egypt, 22 composite soil samples were screened and characterized from citrus and olive orchard soil in contrast to a control soil that had never been cultivated (a nearby desert). The isolates were identified and tested for P solubilization and IAA production to highlight their potential as biofertilizers while the sampled soil was characterized. The physicochemical characteristics of the orchard's soil sample had a high relative mean moisture content, and the C/N ratio were 45.24% and 16.8% compared with desert lands of 32.80% and 8.12%, respectively, while a higher pH was recorded for desert lands. A total of 272 fungal isolates yielded 27 filamentous fungal species. Based on ITS molecular identification, the 27 isolates belonged to phyla Ascomycota, from eight genera. Twelve species were positive in producing a phosphate clearance zone around the fungal colony growth, while ten species were able to release IAA in vitro with different tryptophan concentrations under different pH values. When known pathogenic fungi were excluded, Aspergillus tubingensis and A. fumigatus were the highest IAA producers and can solubilize phosphorus. The screening and identification of the fungal diversity of the newly reclaimed land provided insights into potential phosphate solubilizers and plant phytohormones producers (i.e., IAA). Overall, the obtained results can provide primary knowledge that indicates the great potential fungal ability to develop biofertilizers for application in improving the production of immature soil for agriculture reclamation processes and practices.