Extraction and Characterization of Endophytic Fungi

The endophytic fungi P. citrinum TDPEF34 and G. candidum TDPEF20 were isolated as described previously from the roots of healthy and Leaf Brittle-diseased (LBD) date palm, respectively [1 (link)]. Briefly, mycelia from pure cultures of endophytic fungi were inoculated into potato dextrose broth (PDB) medium in Erlenmeyer flasks (Thermo Fisher Scientific, Foster City, CA, USA) and incubated in the shaker-incubator for 3 weeks at 30 °C, 150 rpm. Subsequently, fungal cultures were filtered through Whatman no.1 filter paper (Thomas Scientific, Foster City, CA, USA) and the resulted filtrates were extracted with n-hexane, ethyl acetate (EtOAc) and methanol (MetOH). The extraction was performed trice and the extracts were dried by a rotary evaporator under vacuum at 45 °C and freezing dried to complete dryness. Mycelia of endophytic fungi cultures were rinsed in sterile water and dried in an oven at 60 °C for 48 h. Then, the mycelia were ultrasonically extracted for 30 min in absolute ethanol and extracted in a similar way. The obtained extracts were stored at 4 °C before being used for further study.