Identification of drought-responsive compounds in potato through a combined transcriptomic and targeted metabolite approach

Abstract

Two potato clones (Solanum tuberosum L.) of the Andean cultivar group, called Sullu and SS2613, with different drought-tolerance phenotypes were exposed to a continuously increasing drought stress in a field trial. At the physiological level, while relative leaf water contents were similar in both clones, osmotic potential was lower in Sullu and declined more strongly during drought compared with SS2613. In the drought-stressed plants, tuber yield was reduced by about 70% compared with control plants in both clones. Potato cDNA microarrays and target metabolite analysis were performed on leaves sampled at several time-points after the onset of drought. At the transcriptomic level, photosynthesis-related genes were already strongly repressed in Sullu after 28 d of withholding irrigation and even more strongly after a longer stress duration, whereas, in SS2613, repression occurred only after 49 d of soil drying; similarly, a strong perturbation of carbohydrate-related genes was observed in Sullu. At the metabolite level, differential accumulation of osmotically active solutes was observed between the two cultivars; indeed, in Sullu, contents of galactose, inositol, galactinol, proline, and proline analogues were higher upon drought stress compared with SS2613. These results point to different drought responses in the cultivars at the leaf level, with, however, similar tuber yield reductions. The previously shown tolerant clone Sullu lost part of its tolerance under the experimental conditions used here; it was, however, able to maintain an absolute yield three times higher than SS2613.

Proline levels, oxidative metabolism and photosynthetic pigments during in vitro growth and acclimatization of Pitcairnia encholirioides L.B. Sm. (Bromeliaceae)

“…The osmotic adjustment is an important response to harmful conditions, which occurs through the accumulation of compatible solutes (Hoekstra et al, 2001;Evers et al, 2010), molecules that maintain the water absorptive capacity and improve the drought tolerance (Kishor et al, 1995). Proline accumulation occurs due to the increase in synthesis and reduction in degradation, being one of the most frequent physiological responses induced by osmotic stress in plants .…”

Essential Role of Tissue-Specific Proline Synthesis and Catabolism in Growth and Redox Balance at Low Water Potential

“…The highest levels of Pro accumulation are typically seen in response to low c w with lower levels accumulating in response to salt or cold (Kaplan et al, 2007;Sharma and Verslues, 2010). Ecophysiological observations have also suggested a role of Pro in drought adaptation (Ben Hassine et al, 2008;Parida et al, 2008;Evers et al, 2010). However, even in Arabidopsis, the role of Pro in low-c w stress is not clearly established and the specific effects of Pro on low-c w resistance have been relatively less studied than salt or cold stress .…”

MOL2NET: FROM MOLECULES TO NETWORKS (PROCEEDINGS BOOK), 2017, 3rd edition.

“…This drop was more pronounced in the susceptible variety, perhaps indicating that the resistant variety was more capable of expressing this gene at normal levels even under the stressful drought conditions. Heat shock proteins are chaperone molecules that stabilize structures of proteins by preventing denaturation during stress (Evers et al, 2010). Triacylglycerol lipase is almost unchanged in transcript level in the susceptible variety but shows a decrease during the drought recovery period in the resistant variety.…”