Quantitative proteomic analysis of differentially expressed proteins in tubers of potato plants differing in resistance to Dickeya solani

This study aims the detection of proteins associated with increased resistance of tubers to necrotrophic bacteria Dickeya solani in tetraploid and diploid potato plants. Comparative analysis of differently expressed proteins in tuber tissue of potato cultivars and diploid interspecific hybrids of Solanum, differing in resistance to Dickeya solani, was performed using nano-liquid chromatography coupled with tandem mass spectrometry (LC-MS-MS/MS). Two highly resistant (Bea and Humalda) and three susceptible (Irys, Katahdin, Ulster Supreme) potato cultivars, and the highly resistant (DG 00–270) and the susceptible (DG 08–305) diploid clones, were studied. Proteins were extracted from wounded potato tubers inoculated with bacteria at an early symptomatic phase of infection and from controls, i.e., intact tubers and wounded mock-inoculated tubers. Data are available via ProteomeXchange with identifier PXD013009. Eight constitutive differentially expressed proteins with fold changes ≥1.9 and q-value ≤0.1 between the resistant and susceptible cultivar groups after D. solani infection were selected. Probable inactive patatin-03-Kuras 1 and the proteinase inhibitor PTI exhibited significantly increased protein abundances after bacterial inoculation in both resistant cultivars compared to the susceptible cultivars. In the diploid clones, only metallocarboxypeptidase and metallocarboxypeptidase-like inhibitors exhibited much higher fold changes following pathogenic invasion (274.4- and 368.6-fold, respectively) than after mock inoculation (165.5- and 130.7-fold, respectively). These results show that different proteins indicating significant fold changes between the resistant and susceptible potato cultivars and diploid clones are induced at an early phase of symptomatic D. solani infection.