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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.

The present study demonstrates how different potato virus Y (PVY) strains affect the miRNA balance in tobacco cv. Samsun. The two prevalent strains PVYNTN and PVYN−Wi caused severe and mild veinal necrosis (VN) respectively, and the unique PVYZ-NTN strain induced milder vein clearing (VCl) in the upper non-inoculated leaves. A single amino acid polymorphisms (SAPs) I252V and a Q412 to R412 substitution in the HC-Pro cistron of the PVYZ-NTN strain might relate to the loss of VN in tobacco. The abundance of 18 out of the 26 tested miRNAs was increased upon infection by the severe strains PVYNTN and PVYN−Wi. Expression of a group of defense related transcripts were increased accordingly. Two miRNAs, nta-miR6020a-5p and nta-miR6164a/b, which target the TIR-NBS-LRR type resistant TMV N genes involving in signal transduction, might correlate with the PVYNTN and PVYN-Wi induced VN. The down-regulated mRNAs, e.g., RAP2-7 and TOE3, PXC3, LRR-RLK, ATHB-14 and TCP4 targeted by nta-miR172, nta-miR390, nta-miR482, nta-miR166 and nta-miR319/159 respectively, were related to regulation of transcription, protein phosphorylation and cell differentiation. The observed strain-specific alteration of miRNAs and their targets are host dependent and corresponds to the symptom severity and the viral HC-Pro RNA levels.

Here we optimized an efficient and reproducible method for proteins isolation from potato tubers for quantitative proteomic analysis, aimed at detection of differentially expressed proteins upon various experimental conditions.

This study demonstrates the new sources of resistance available in potato cv. Etola, which represent multiple strain-specific resistance genes against three strains of Potato virus Y (PVY). Etola is the first documented cultivar of this sort in Europe that exhibits hypersensitive resistance (HR) to PVYNTN isolate PVY-3202, and different levels of partial resistance to PVYN-Wi isolate PVY-3411 and PVYZ-NTN isolate PVY-3303. The isolate PVY-3411 induced severe symptoms and faster systemic viral coat protein and RNA accumulation in the noninoculated upper leaves, whereas PVY-3303 caused mild symptoms and delayed viral spreading. This study provides the first example of strain-specific alteration of a set of host microRNAs (miRNAs) and their targets in the potato–PVY interaction. The tested miRNAs and targets are altered only in plants of cv. Etola infected with PVY-3411 but not those infected with PVY-3303 nor PVY-3202. The up-regulation of stu-miR162, stu-miR168a and miR172e, together with their target transcripts, DCL1, AGO1-2 and TOE3, respectively, in PVY-3411-infected plants correlates with high abundance of HC-Pro RNA encoding an RNA-silencing suppressor and might be linked with the severe symptoms in leaves. Moreover, PVY-3411 causes parallel increases in two members of stu-miR482 and their mRNA targets Gpa2 and CC-NBS-LRR that are involved in the defence response.

The phytotoxic abilities of potato (Solanum tuberosum L.), in a population consisting of wild species, potato diploid hybrids and potato cultivars, against mustard (Sinapis alba L.) were investigated. Measurements of total glycoalkaloid, phenolic and flavonoid concentrations in potato leaf extracts and their role in phytotoxicity were performed. Extracts prepared from wild potato species, particularly Solanum maglia and Solanum chacoense, had the strongest inhibitory effect on mustard growth. Most extracts significantly extended the germination time, as determined by Piepper’s index, but extracts prepared from potato cultivars did not affect seedling growth/development. However, only S. maglia and S. chacoense prolonged the time of germination, corresponding to inhibition of mustard growth. The Pearson’s correlation coefficient of concentrations of total glycoalkaloids, phenolics and flavonoids in potato leaf extracts and length of mustard seedlings showed a significant negative correlation for glycoalkaloids (r = − 0.51), with the strongest effect for root length of potato wild species (r = − 0.79) and potato diploid hybrids (r = − 0.86). Our data indicated that glycoalkaloids are the major phytotoxic compounds responsible for potato phytotoxicity against mustard. However, we observed phenolics and flavonoids may influence the strength of the phytotoxic effects caused by glycoalkaloids.