Diversity, Tolerance and Antioxidant Enzymes of Indigenous Fungi Isolated from Xerophytes Grown in Stressed Soil

Introduction: This study aimed at isolating and characterizing endophytic fungi from xerophytic plants collected from Egypt west deserts.Materials and Methods: Soil samples and different plant species were collected from Egypt west deserts. The pH and electrical conductivity of soil samples were measured. Endophytic fungi were then isolated from collected plants and identified. Salt and pH tolerance of fungal species were assessed. Antioxidant enzymes of the most tolerant fungi were screened.Results: The collected soil samples were highly saline and alkaline compared to Nile shore soil. Czapak Doxʹs agar media was the most suitable tested media for catching the highest count of endophytes from the xerophytic plants Kochia indica, Zygophyllum coccineum, Amaranthus viridis L, and Dodonaea viscosa. Moreover, D. viscosa was colonized with a high count of endophytic fungi. Low diversity of indigenous fungi was detected, where the ۳۶ endophytic isolates constituted only four species. The tolerance assay toward different concentrations of salt and pH values proved that A. terreus and A. flavus were halotolerant and alkali-tolerant species, where they tolerate up to ۳ M NaCl and pH values up to ۱۱. Molecular identification of the most tolerant isolates resulted in Aspergillus terreus and Aspergillus flavus with accession numbers OQ۲۷۱۴۴۶ and OQ۲۷۱۴۵۶, respectively. It was found that the two antioxidant enzymes catalase and peroxidase displayed significant increases in their activity under high salinity and alkalinity compared to the control.Conclusions: The isolated fungi were tolerant to salinity and alkalinity which significantly stimulate the antioxidant enzyme activities of these fungal species.

Keywords:

Xerophytes , Endophytes , Stressed Soil , Antioxidant enzymes