(A) Performance of the internal ligation control. The PRI-lock probe mixture was ligated using varying ligation reaction temperatures on a 10-fold serial dilution of P. infestans target and amplified in conventional real-time PCR using the P. infestans and the ILC PRI-lock probe specific primer pairs. The P. infestans PRI-lock probe CT value was normalized using the ILC CT value as described in the Materials and Methods section. P. infestans CT values without normalization (x). Normalized P. infestans CT values (▪). (B) Calibration curves to assess the sensitivity and linear range of quantification of the P. infestans PRI-lock probe in conventional real-time PCR (red) and in the Biotrove OpenArray™ platform (green). The PRI-lock probe mixture was ligated on a 10-fold P. infestans target dilution series and amplified in real-time PCR using the P. infestans PRI-lock probe specific primer pair. CT values were normalized using the ILC control PRI-lock probe. Data represent average CT values of six PCR replicates (n = 6). The standard deviation error bars fall within the data squares.