Fig 4.

Measurement of tyrosinase activity in individual lines from Saprolegnia parasitica treated with dsRNA. Sporulating mycelium from all individual lines treated with dsRNA was collected and enzyme activity tested using a spectrophotometric assay (Winder 1994) as described in Material and Methods. The rate of oxidation of l-DOPA into dopaquinone by the tyrosinase was determined after 30 min of incubation at 37 °C. The amount of forming product is determined by measuring absorbance at 505 nm. SpTyr-dsRNA individual lines Tyr1 to Tyr7 present the lowest tyrosinase activity, corresponding to the highest silencing level achieved. Note that the same individual lines used to assess the gene expression level (Fig 2) were used for the enzyme activity measurements and melanin content analysis (Fig 5). The error bars represent the standard error within technical triplicates.