Comparison of leaf proteomes of potato (<Emphasis Type="BoldItalic">Solanum tuberosum</Emphasis> L.) genotypes with ER- and HR-mediated resistance to PVY infection

The Ny-1 and Ry-fsto genes of potato (Solanum tuberosum L.) confer hypersensitive response (HR) and extreme resistance (ER), respectively, to Potato virus Y (PVY). ER-type resistance was also observed in potato plants with both alleles (Ny-1 and Ry-fsto). Using two-dimensional electrophoresis (2-DE), quantitative differences between PVY-infected and non-infected control plants were found for 35, 32 and 15 protein spots identified in leaves of potato cultivar Rywal (possessing Ny-1), and potato tetraploid clones PW 363 (with Ry-fsto) and PB 08–137 (with Ny-1 + Ry-fsto), respectively. We recognized 29, 12 and 21 PVY-induced protein spots involved in qualitative changes in Rywal, PW 363 and PB 08–137 plants, respectively, which were processed and analysed using a liquid chromatography-tandem mass spectrometry (LC-MS/MS) system. A database search indicated that these 62 proteins belong to various functional categories. Their expression was genotype-specific. In the case of cultivar Rywal with HR-mediated resistance, proteins involved in photosynthesis and primary metabolism were the most abundant. For PW 363 and PB 08–137, both with ER–mediated resistance, stress-responsive proteins were the most numerous. Only two proteins – glutamate–glyoxylate aminotransferase 2 (GGAT2) and monodehydroascorbate reductase 5 (MDHAR5) – were identified in all three genotypes. These two proteins are components of the reactive oxygen species (ROS) defence mechanism against pathogens in plants. The present study showed that the differences in PVY-induced proteins in the leaves of Ny-1, Ry-fsto and Ny-1 + R-fsto genotypes do not correspond to the type of gene conferring the resistance or to the observed phenotype.