Effects of exogenous putrescine on glycolysis and Krebs cycle metabolism in cucumber leaves subjected to salt stress
- 600 Downloads
The effects of exogenous putrescine (8 mmol L−1) on the carbohydrate content, glycolytic metabolism, citric acid cycle intermediates, key enzyme activities and their corresponding gene expression in cucumber (cucumis sativus L. cv. Jingyou NO.4) subjected to salt stress (75 mmol L−1 NaCl) in solution culture was studied. Phosphofructokinase (PFK), pyruvate kinase (PK) and phosphoenolpyruvate pyruvate kinase (PEPC) activities were significantly decreased in leaves when exposed to salt stress. NaCl stress caused the PFK and PK gene expression and the content of pyruvate to significantly decrease, while PEPC gene expression increased. Salt stress also significantly reduced isocitrate dehydrogenase, malate dehydrogenase and succinate dehydrogenase and their levels of transcription, causing decreases in the citric acid, succinic acid and malic acid content in leaves. Exogenous putrescine reversed the salt stress and increased gene expression and, in turn, the key enzymes involved in the glycolysis pathway and Krebs cycle, which significantly increased the amounts of organic acids and pyruvate produced, promoting the release of more energy currency (ATP and ADP). These results suggest that Put effectively participate glycolysis pathway and Krebs cycle, reducing the excessive accumulation of carbohydrates in the leaves, and providing more material and energy for the defense salt-induced injury, thus enhances cucumber seedling to salt stress tolerance.
KeywordsCucumber Putrescine Salt stress Glycolysis pathway Krebs cycle Gene expression
This work was financially supported by the National Natural Science Foundation of China (Nos. 31471869, 31401919 and 31272209), the China Postdoctoral Science Foundation Funded Project (2014M561665), the China Earmarked Fund for Modern Agro-industry Technology Research System (CARS-25-C-03), and the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD), and sponsored by the Research Fund for the Doctoral Program of Higher Education (20130097120015)..
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
- Bergmeyer H et al (1974) Enzymes as biochemical reagents: hexokinase. Methods Enzym Anal 1:473Google Scholar
- Chen LF, Lu W, Sun J, Guo SR, Zhang ZX, Yang YJ (2011) Effects of exogenous spermidine on photosynthesis and carbohydrate accumulation in roots and leaves of cucumber (Cucumis sativus L.) seedlings under salt stress. J Nanjing Agric Univ 3:007Google Scholar
- Liu H, Jiang Y, Luo Y, Jiang W (2006) A simple and rapid determination of ATP, ADP and AMP concentrations in pericarp tissue of litchi fruit by high performance liquid chromatography. Food Technol Biotechnol 44(4):531–534Google Scholar
- Poor P, Gemes K, Horvath F, Szepesi A, Simon ML, Tari I (2011) Salicylic acid treatment via the rooting medium interferes with stomatal response, CO2 fixation rate and carbohydrate metabolism in tomato, and decreases harmful effects of subsequent salt stress. Plant Biology 13(1):105–114CrossRefPubMedGoogle Scholar
- Sudha G, Ravishankar G (2002) Involvement and interaction of various signaling compounds on the plant metabolic events during defense response, resistance to stress factors, formation of secondary metabolites and their molecular aspects. Plant Cell Tissue Organ Cult 71(3):181–212CrossRefGoogle Scholar
- Zhao J, Zuo K, Tang K (2004) cDNA cloning and characterization of Enolase from chinese cabbage, Brassica campestris ssp. Pekinensis. Mitochondrial DNA 15(1):51–57Google Scholar