Expression of biotic stress response genes to Phytophthora infestans inoculation in White Lady, a potato cultivar with race-specific resistance to late blight

• Stress response genes were analyzed by qPCR in P. infestans-potato interaction.
• Twelve of the sixteen genes showed up-regulation after infection.
• Up-regulation of ten genes occurred in biotrophic phase accelerating resistance.
• Whole genomic transcriptome data were used and compared with qPCR data.

Expression changes of biotic stress response genes were analyzed during a 65 h period post inoculation with Phytophthora infestans in potato cultivar White Lady that possesses race-specific resistance to this pathogen. All analyzed respiratory burst oxidase homologs, the PR proteins, the serine-, cysteine- and aspartic protease inhibitors, as well as the Rpi-bt1 gene homolog were up-regulated in the biotrophic phase. The R1 and R2 gene homologs showed up-regulation only at 65 hpi, and interestingly, the R3a gene showed only a very slight expressional increase. It is concluded, that beside the constitutively expressed R genes a number of non-specific stress response genes contribute to the successful resistance response in race-specific defense.