Bioactivity of magnesium oxide nanoparticles synthesized from cell filtrate of endobacterium Burkholderia rinojensis against Fusarium oxysporum.

The present study was performed to synthesize, for the first time, the magnesium oxide nanoparticles (MgO NPs) using the cell filtrate of the endobacterium Burkholderia rinojensis. The MgO NPs were characterized by Ultraviolet-visible (UV-Vis), Fourier-transform infrared (FTIR), X-ray diffraction (XRD), Energy dispersive X-ray (EDX), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and zeta potential (ZP). The UV spectrum of the MgO NPs showed a sharp absorption peak at 330 nm. The FTIR results confirm that the bioactive compounds act as reducing and capping agents of synthesized MgO NPs. The XRD pattern showed three major peaks of the crystalline metallic MgO NPs. Presence of magnesium and oxygen were confirmed by EDX profile. Both SEM and TEM revealed the MgO NPs as roughly spherical granular structures, and the size was 26.70 nm. The zeta potential was -32.1 mV, which indicated the stability of the MgO NPs in suspension. The MgO NPs showed considerable antifungal and antibiofilm activities against Fusarium oxysporum f. sp. lycopersici. At the concentration of 15.36 μg/ml, the MgO NPs completely inhibited the mycelial growth of the fungus. The biofilm formation of the pathogen was completely suppressed by MgO NPs at 1.92 μg/ml. The MgO NPs caused severe morphological changes on the hyphal morphology and biofilm formation of the fungus with significant damage on the fungal membrane integrity.