Mycelial Growth Inhibition by Metabolites

To determine the mycelial growth inhibition (MGI) by metabolites isolated from ST1-UCA (see Section 2.4.1), plates containing 10 mL of PDA medium supplemented with increasing amounts of the inhibitory substances (diluted in ethanol) under study were prepared. Negative controls were prepared using an equal quantity of the ethanol that was used to dilute inhibitory substances. Positive controls were prepared using dicloran at different concentrations (0,5-1-2,5-5-15-35-70 μg·mL⁻¹). All PDA plates were inoculated using five-day-old mycelial plugs (7 mm) from B. cinerea B05.10. The plates were incubated at 25 °C for 7 days under 24 h of daylight, and radial mycelial growth was measured daily for 4 days. All conditions were assayed in triplicate.
$$\mathrm{M}\mathrm{G}\mathrm{I}:\frac{\mathrm{d}\mathrm{c}-\mathrm{d}\mathrm{t}}{\mathrm{d}\mathrm{c}}\times 100$$
IMG was calculated as described by Simionato et al. (2017) [67 (link)]. In the expression, dc (mm) represents the mean value of B. cinerea radial growth in negative control plates, and dt (mm) represents the mean value of B. cinerea radial growth in each treatment. The 50% effective dose (ED50) was determined through regression analysis when growth was reduced by 50% compared to the control.