Effect of the biomass of the cyanobacterium Nostoc commune on the growth of Fusarium oxysporum "In vitro"

The cyanobacteria Nostoc commune contains bioactive compounds with antimicrobial activity and high potential to control of phytopathogens. The objective of this work was to determine the in vitro effect of sonicated biomass of these cyanobacteria on the growth of Fusarium oxysporum. The biomass of N.commune was dissolved in sterile distilled water and subjected to centrifugation processes and ultrasound-assisted cell rupture. The antifungal effect was evaluated using the disk diffusion technique (Kirby-Bauer) in a PDA (Potato Dextrose Agar) medium. In the center of the Petri dish, an agar disk (0.7 cm) with pure mycelium of the fungus was placed in the center of the Petri dish and, around it, four filter paper disk impregnateed with the algae extract (0.7 cm) were placed. The radial growth of the pathogen was measured in the presence and absence of N. commune, until the control covered the entire Petri dish to assess the Percentage of Radial Inhibition of the pathogen (PICR %). The growth rate of the fungus was lower in the initial stages of measurement and the PICR fluctuated between 33 and 58%. However, there were no inhibition halos in the growth of the fungus, it is assumed that the antifungal effect of the cyanobacteria was not permanent over the time, but it could be potentiated by improving the extraction process of the extract.