Gene expression study after 1 and 3 days of salt exposure in a Solanum tuberosum cultivar called PS3

The molecular response to salt exposure was studied in the leaves of a S. tuberosum clone using cDNA microarray. Differentially expressed genes were classified according to their known or predicted function and their expression ratio as compared to the control. The major changes upon a 150 mM NaCl exposure in potato leaves occurred in the photosystem apparatus and Calvin cycle: many transcripts coding for proteins belonging to photosystems I and II and chlorophyll synthesis were repressed. On the other hand, we observed the induction of various kinds of transcription factors implicated in osmotic stress response via ABA-dependent or ABA-independent pathways but also in plant defense pathways. This revealed a crosstalk between abiotic and biotic stress responses during salt exposure, which activated several adaptation mechanisms including HSP, LEA, dehydrins and PR proteins. Gene expression changes related to carbohydrate and amino acid metabolism were also observed, pointing at putative modifications at the metabolic level. Gene expression has been followed at two different time-points (one and three day after salinity treatment) and conditions: salt-treatment (150 mM NaCl) and control conditions. For each time-point and conditions 3 independent biological replicates were sampled.