Effect of Short-Term Cold Treatment on Carbohydrate Metabolism in Potato Leaves

Abstract

Plants are often challenged by an array of unfavorable environmental conditions. During cold exposure, many changes occur that include, for example, the stabilization of cell membranes, alterations in gene expression and enzyme activities, as well as the accumulation of metabolites. In the presented study, the carbohydrate metabolism was analyzed in the very early response of plants to a low temperature (2 °C) in the leaves of 5-week-old potato plants of the Russet Burbank cultivar during the first 12 h of cold treatment (2 h dark and 10 h light). First, some plant stress indicators were examined and it was shown that short-term cold exposure did not significantly affect the relative water content and chlorophyll content (only after 12 h), but caused an increase in malondialdehyde concentration and a decrease in the expression of NDA1, a homolog of the NADH dehydrogenase gene. In addition, it was shown that the content of transitory starch increased transiently in the very early phase of the plant response (3–6 h) to cold treatment, and then its decrease was observed after 12 h. In contrast, soluble sugars such as glucose and fructose were significantly increased only at the end of the light period, where a decrease in sucrose content was observed. The availability of the monosaccharides at constitutively high levels, regardless of the temperature, may delay the response to cold, involving amylolytic starch degradation in chloroplasts. The decrease in starch content, observed in leaves after 12 h of cold exposure, was preceded by a dramatic increase in the transcript levels of the key enzymes of starch degradation initiation, the α-glucan, water dikinase (GWD-EC 2.7.9.4) and the phosphoglucan, water dikinase (PWD-EC 2.7.9.5). The gene expression of both dikinases peaked at 9 h of cold exposure, as analyzed by real-time PCR. Moreover, enhanced activities of the acid invertase as well as of both glucan phosphorylases during exposure to a chilling temperature were observed. However, it was also noticed that during the light phase, there was a general increase in glucan phosphorylase activities for both control and cold-stressed plants irrespective of the temperature. In conclusion, a short-term cold treatment alters the carbohydrate metabolism in the leaves of potato, which leads to an increase in the content of soluble sugars.

Genome Assembly of Alfalfa Cultivar Zhongmu-4 and Identification of SNPs Associated with Agronomic Traits

“…The Msa0924940 homologs in M. truncatula encode NADH dehydrogenases. Some members of this gene family were reported to mediate cold and some other environment stresses in Arabidopsis and potato [40] , [41] . Dormancy is highly correlated with low-temperature stress responses in alfalfa [42] .…”

In Silico Characterization and Expression Analysis of GIGANTEA Genes in Potato

“…In each RT-qPCR assay one biological sample representing 3–5 plants was tested in three technical replicates. The efficiency of stress treatments was monitored by testing the Δ1-PYRROLINE-5-CARBOXYLATE SYNTHETASE ( P5CS ; Liu et al 2019 ), α-GLUCAN, WATER DIKINASE ( GWD ; Orzechowski et al 2021 ) and HEAT SOCK PROTEIN 20–44 ( HSP20-44 ; Zhao et al 2018 ) mRNA levels. The gene IDs and primer sequences are listed in Table S1.…”

Starch metabolism in potato <i>Solanum tuberosum</i> L.

“…They phosphorylate glucans at positions C6 and C3 of glucose residues, making them more hydrophilic and allow α-, β-, and isoamylases access to them (see the Table) (Ritte et al, 2006;Streb, Zeeman, 2012). The phosphorylation by GWD seems to play the key role in starch degradation in potato tubers and leaves (Claassen et al, 1993;Orzechowski et al, 2021). Tubers of transgenic potato plants with lower expression of the StGWD gene were less prone to starch degradation at low temperatures (Lorberth et al, 1998).…”