Drought‐Induced Memory Affects Photosynthetic Performance in Potato Cultivars ( Solanum tuberosum L.)

Photosynthesis is the main determinant of crop yield. Drought is reported to be one of the major abiotic stresses that negatively affect photosynthetic capacity. This is the first report on the effect of drought‐induced memory on the photosynthetic activity of potato. Two potato cultivars, Cayuga and Dalila, which were grown under non‐stressed conditions, were studied. The plants were propagated from seed tubers that were produced by plants grown under non‐restricted (non‐primed tubers) and restricted (drought‐primed tubers) water conditions. In Dalila plants, 14 JIP‐test parameters were significantly altered in drought‐primed plants, as compared to the control, of which PI inst , PI ABS and DF ABS showed the highest values. In Cayuga plants, the observed changes in JIP‐test parameters were not significant. In contrast, there was no significant variation in the photosynthetic pigment content (chlorophyll a , chlorophyll b and carotenoids) in drought‐primed Dalila plants, whereas drought‐primed Cayuga plants had significantly higher values for leaf pigment content compared to the control. In Dalila and Cayuga plants, cell cycle progression was not affected by drought‐induced memory. Gene ontology (GO) annotation and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment for differentially expressed genes (DEGs) in drought‐primed Dalila plants showed that photosynthesis‐related pathways may be essential in response to drought‐induced memory. The top three categories included ‘photosynthesis, light harvesting in photosystem I’, ‘response to light stimulus’ and ‘photosynthesis‐antenna proteins’. In contrast, only a few DEGs were observed in the progeny of Cayuga‐primed vs. Cayuga‐non‐primed plants. Potato tubers are strong sink organs. Our results suggest that the maintenance or fading of drought‐induced memory involves processes related to photosystem activity, which may result in the observed variation in potato tuber productivity under non‐stressed conditions.