scholarly journals Applying Spermidine for Differential Responses of Antioxidant Enzymes in Cucumber Subjected to Short-term Salinity

2010 ◽  
Vol 135 (1) ◽  
pp. 18-24 ◽  
Author(s):  
Chang-Xia Du ◽  
Huai-Fu Fan ◽  
Shi-Rong Guo ◽  
Takafumi Tezuka

To examine whether spermidine (SPD) modifies plant antioxidant enzyme expression in response to short-term salt stress, cucumber (Cucumis sativus) seedlings were treated with NaCl in the presence or absence of SPD for 3 days. Compared with untreated control plants, free radical production and malondialdehyde content in leaves and roots increased significantly and plant growth was suppressed under 50 mm NaCl stress. Exogenous SPD sprayed on leaves at a concentration of 1 mm alleviated salinity-mediated growth reduction. Salt stress caused a consistent increase in soluble protein content, as well as peroxidase (POD) and superoxide dismutase (SOD) activities in cucumber seedlings. By native polyacrylamide gel electrophoresis, five POD isozymes were detected in cucumber seedling leaves, and seven in roots. We detected five SOD isozymes in leaves and four in roots, and two catalase (CAT) isozymes in leaves and two in roots. Our results indicate that salt stress induced the expression of POD and SOD isozymes in cucumber seedlings, but inhibited the expression of CAT isozymes in roots. Application of exogenous SPD further increased POD and SOD expression and activity, and led to the differential regulation of CAT in leaves and roots. These data show that antioxidant enzymes, especially POD and SOD, appear to protect cucumber seedlings against stress-related damage, and they appear to function as the molecular mechanisms underlying the response of cucumber seedlings to salinity. Moreover, SPD has potential to scavenge directly free radical and to alleviate growth inhibition and promote the activity and expression of antioxidant system enzymes in cucumber seedlings under short-term salt stress.

2020 ◽  
Author(s):  
Jingjing Wang ◽  
Cong An ◽  
Hailin Guo ◽  
Xiangyang Yang ◽  
Jingbo Chen ◽  
...  

Abstract Background: Areas with saline soils are sparsely populated and have fragile ecosystems, which severely restricts the sustainable development of local economies. Zoysia grasses are recognized as excellent warm-season turfgrasses worldwide, with high salt tolerance and superior growth in saline-alkali soils. However, the mechanism underlying the salt tolerance of Zoysia species remains unknown. Results: The phenotypic and physiological responses of two contrasting materials, Zoysia japonica Steud. Z004 (salt sensitive) and Z011 (salt tolerant) in response to salt stress were studied. The results show that Z011 was more salt tolerant than was Z004, with the former presenting greater K+/Na+ ratios in both its leaves and roots. To study the molecular mechanisms underlying salt tolerance further, we compared the transcriptomes of the two materials at different time points (0 h, 1 h, 24 h, and 72 h) and from different tissues (leaves and roots) under salt treatment. The 24-h time point and the roots might make significant contributions to the salt tolerance. Moreover, GO and KEGG analyses of different comparisons revealed that the key DEGs participating in the salt-stress response belonged to the hormone pathway, various TF families and the DUF family. Conclusions: Z011 may have improved salt tolerance by reducing Na+ transport from the roots to the leaves, increasing K+ absorption in the roots and reducing K+ secretion from the leaves to maintain a significantly greater K+/Na+ ratio. Twenty-four hours might be a relatively important time point for the salt-stress response of zoysiagrass. The auxin signal transduction family, ABA signal transduction family, WRKY TF family and bHLH TF family may be the most important families in Zoysia salt-stress regulation. This study provides fundamental information concerning the salt-stress response of Zoysia and improves the understanding of molecular mechanisms in salt-tolerant plants.


2020 ◽  
Vol 21 (17) ◽  
pp. 6036
Author(s):  
Qiushuo Song ◽  
Madhumita Joshi ◽  
Vijay Joshi

Watermelon (Citrullus lanatus L.) is a widely popular vegetable fruit crop for human consumption. Soil salinity is among the most critical problems for agricultural production, food security, and sustainability. The transcriptomic and the primary molecular mechanisms that underlie the salt-induced responses in watermelon plants remain uncertain. In this study, the photosynthetic efficiency of photosystem II, free amino acids, and transcriptome profiles of watermelon seedlings exposed to short-term salt stress (300 mM NaCl) were analyzed to identify the genes and pathways associated with response to salt stress. We observed that the maximal photochemical efficiency of photosystem II decreased in salt-stressed plants. Most free amino acids in the leaves of salt-stressed plants increased many folds, while the percent distribution of glutamate and glutamine relative to the amino acid pool decreased. Transcriptome analysis revealed 7622 differentially expressed genes (DEGs) under salt stress, of which 4055 were up-regulated. The GO analysis showed that the molecular function term “transcription factor (TF) activity” was enriched. The assembled transcriptome demonstrated up-regulation of 240 and down-regulation of 194 differentially expressed TFs, of which the members of ERF, WRKY, NAC bHLH, and MYB-related families were over-represented. The functional significance of DEGs associated with endocytosis, amino acid metabolism, nitrogen metabolism, photosynthesis, and hormonal pathways in response to salt stress are discussed. The findings from this study provide novel insights into the salt tolerance mechanism in watermelon.


2015 ◽  
Vol 112 (34) ◽  
pp. E4792-E4801 ◽  
Author(s):  
Guiling Zhao ◽  
Tianyu Li ◽  
Didier X. P. Brochet ◽  
Paul B. Rosenberg ◽  
W. J. Lederer

In ventricular myocytes, the physiological function of stromal interaction molecule 1 (STIM1), an endo/sarcoplasmic reticulum (ER/SR) Ca2+ sensor, is unclear with respect to its cellular localization, its Ca2+-dependent mobilization, and its action on Ca2+ signaling. Confocal microscopy was used to measure Ca2+ signaling and to track the cellular movement of STIM1 with mCherry and immunofluorescence in freshly isolated adult rat ventricular myocytes and those in short-term primary culture. We found that endogenous STIM1 was expressed at low but measureable levels along the Z-disk, in a pattern of puncta and linear segments consistent with the STIM1 localizing to the junctional SR (jSR). Depleting SR Ca2+ using thapsigargin (2–10 µM) changed neither the STIM1 distribution pattern nor its mobilization rate, evaluated by diffusion coefficient measurements using fluorescence recovery after photobleaching. Two-dimensional blue native polyacrylamide gel electrophoresis and coimmunoprecipitation showed that STIM1 in the heart exists mainly as a large protein complex, possibly a multimer, which is not altered by SR Ca2+ depletion. Additionally, we found no store-operated Ca2+ entry in control or STIM1 overexpressing ventricular myocytes. Nevertheless, STIM1 overexpressing cells show increased SR Ca2+ content and increased SR Ca2+ leak. These changes in Ca2+ signaling in the SR appear to be due to STIM1 binding to phospholamban and thereby indirectly activating SERCA2a (Sarco/endoplasmic reticulum Ca2+ ATPase). We conclude that STIM1 binding to phospholamban contributes to the regulation of SERCA2a activity in the steady state and rate of SR Ca2+ leak and that these actions are independent of store-operated Ca2+ entry, a process that is absent in normal heart cells.


2011 ◽  
Vol 361-363 ◽  
pp. 90-93
Author(s):  
Zhao Xiang Han ◽  
Gui Quan Han ◽  
Zhang Meng ◽  
Chun Xia Lv

This study was aimed at obtaining detailed information about the interaction of NaCl salinity and elevated atmospheric CO2concentration in the halophyte S.salsa, which was irrigated with five different salinity levels under ambient and elevated (530 ppm) CO2. The results show that total soluble sugar concentration was significantly increased by salt-treatments in both leaves and roots, and that the most progressive sugar increments were observed in leaves and roots of S. salsa under the elevated CO2. The Na+ concentration in the leaves and roots increased with the increased NaCl concentration, the K+ accumulation gradually decreaed by increasing salinity levels in leaves and roots. Proline increased in response to salt stress along with incremental NaCl concentration. The GB concentrations of leaves were significantly raised as NaCl levels increased. Electrolyte leakage increased in the leaves of S. salsa grown under NaCl stress. ψs of leaves and roots decreased as the NaCl concentration increase, and that elevated CO2both had markedly greater effects on ψs of leaves and roots. The osmotic adjustment values ascended with elevated CO2concentration in both leaves and roots.


Author(s):  
Mohammad Akbari ◽  
Ramesh katam ◽  
Rabab Husain ◽  
Mostafa Farajpour ◽  
Silvia Mazzuca ◽  
...  

Salinity substantially affects plant growth and crop productivity worldwide. Plants adopt several biochemical mechanisms including regulation of antioxidant biosynthesis to protect themselves against the toxic effects induced by the stress. One-year-old Pistachio rootstock exhibiting different degrees of salinity tolerance were subjected to sodium chloride induced salt stress to identify genetic diversity among cultivated pistachio rootstock for their antioxidant responses, and to determine the correlation of these enzymes to salinity stress. Leaves and roots were harvested following NaCl-induced stress. Results show that a higher concentration of NaCl treatment induced oxidative stress in the leaf tissue and to a lesser extent in the roots. Both tissues showed an increase in ascorbate peroxidase, superoxide dismutase, catalase, glutathione reductase, peroxidase and malondialdehyde. Responses of antioxidant enzymes were cultivar dependent, as well as temporal and dependent on the salinity level. Linear and quadratic regression model analysis revealed significant correlation of enzyme activities to salinity treatment in both tissues. The variation in salinity tolerance reflected their capabilities in orchestrating antioxidant enzymes at the roots and harmonized across the cell membranes of the leaves. The study provides a better understanding of root and leaf coordination in regulating the antioxidant enzymes to NaCl induced oxidative stress.


2021 ◽  
Vol 25 (03) ◽  
pp. 591-600
Author(s):  
Huaguang Hu

Zoysia macrostachya Franch. et Sav. is a halophyte with very strong tolerance to salinity, which can serve as an alternative turfgrass for landscaping in saline-alkali land and provide the salt-tolerance genes for turfgrass breeding. To further illustrate the salt-tolerance mechanisms in this species at molecular level, the roots transcriptome of Z. macrostachya was investigated under salt stress using the Illumina sequencing platform. Altogether 47,325 unigenes were assembled, among which, 32,542 (68.76%) were annotated, and 87.61% clean reads were mapped to the unigenes. Specifically, 14,558 unigenes were shown to be the differentially expressed genes (DEGs) following exposure to 710 mM NaCl stress compared with control, including 7972 up-regulated and 6586 down-regulated DEGs. Among these DEGs, 24 were associated with the reactive oxygen species (ROS) scavenging system, 61 were found to be related to K+ and Na+ transportation, and 16 were related to the metabolism of osmotic adjustment substances. Additionally, 2327 DEGs that encoded the transcription factors (TFs) were also identified. The expression profiles for 10 DEGs examined through quantitative real-time PCR conformed to the individual alterations of transcript abundance verified through RNA-Seq. Taken together, results of transcriptome analysis in this study provided useful insights for salt-tolerance molecular mechanisms of Z. macrostachya. Furthermore, these DEGs under salt stress provided important clues for future salt-tolerance genes cloning of Z. macrostachya. © 2021 Friends Science Publishers


2012 ◽  
Vol 137 (3) ◽  
pp. 127-133 ◽  
Author(s):  
Huai-Fu Fan ◽  
Chang-Xia Du ◽  
Shi-Rong Guo

Nitric oxide (NO), an endogenous signaling molecule in plants and animals, mediates responses to abiotic and biotic stresses. This study was conducted in a nutrient solution to investigate 1) the effects of exogenous sodium nitroprusside (SNP), an NO donor, on free proline (Pro) and protein content; and 2) the enzymes involved in Pro metabolism [pyrroline-5-carboxylate synthetase (P5CS) and proline dehydrogenase (PDH)] in cucumber (Cucumis sativus) seedling leaves and roots under NaCl stress. The results showed that the increases in free Pro and protein were significantly higher in the 50 mm NaCl solution but highly significant with the addition of 100 μM SNP to the 50 mm NaCl solution for the entire treatment period. Moreover, leaves maintained higher levels of free Pro and protein content than roots throughout the experiments. The P5CS activity increased in the saline treatment compared with the control, and this increase was greater in the 50 mm NaCl + 100 μM SNP solution than in the other treatments. On the other hand, the PDH activity was inhibited under NaCl stress but the reduction in activity was greater in the 50 mm NaCl + 100 μM SNP solution than in the others. These findings suggest that Pro metabolism was significantly altered during the exogenously applied NO under salt stress and that this alteration prompted the accumulation of higher levels of free Pro, which, in turn, maintained the turgor in the cucumber seedlings and helped protect them from salt stress. Moreover, the toxic effects generated by 50 mm NaCl were partially overcome by the application of NO, which could be used as a potential growth regulator to improve plant salinity tolerance. Therefore, it was concluded that NO could alleviate salinity damage in cucumber seedlings by regulating Pro metabolism. Overall, the adverse effects of salt stress could be lessened by the exogenous application of NO to cucumber seedlings.


2020 ◽  
Author(s):  
Jingjing Wang ◽  
Cong An ◽  
Hailin Guo ◽  
Xiangyang Yang ◽  
Jingbo Chen ◽  
...  

Abstract Background: Areas with saline soils are sparsely populated and have fragile ecosystems, which severely restricts the sustainable development of local economies. Zoysia grasses are recognized as excellent warm-season turfgrasses worldwide, with high salt tolerance and superior growth in saline-alkali soils. However, the mechanism underlying the salt tolerance of Zoysia species remains unknown. Results: The phenotypic and physiological responses of two contrasting materials, Zoysia japonica Steud. Z004 (salt sensitive) and Z011 (salt tolerant) in response to salt stress were studied. The results show that Z011 was more salt tolerant than was Z004, with the former presenting greater K + /Na + ratios in both its leaves and roots. To study the molecular mechanisms underlying salt tolerance further, we compared the transcriptomes of the two materials at different time points (0 h, 1 h, 24 h, and 72 h) and from different tissues (leaves and roots) under salt treatment. The 24-h time point and the roots might make significant contributions to the salt tolerance. Moreover, GO and KEGG analyses of different comparisons revealed that the key DEGs participating in the salt-stress response belonged to the hormone pathway, various TF families and the DUF family. Conclusions: Z011 may have improved salt tolerance by reducing Na + transport from the roots to the leaves, increasing K + absorption in the roots and reducing K + secretion from the leaves to maintain a significantly greater K + /Na + ratio. Twenty-four hours might be a relatively important time point for the salt-stress response of zoysiagrass. The auxin signal transduction family, ABA signal transduction family, WRKY TF family and bHLH TF family may be the most important families in Zoysia salt-stress regulation. This study provides fundamental information concerning the salt-stress response of Zoysia and improves the understanding of molecular mechanisms in salt-tolerant plants.


2013 ◽  
Vol 138 (2) ◽  
pp. 108-113 ◽  
Author(s):  
Bin Li ◽  
Ting Sang ◽  
Lizhong He ◽  
Jin Sun ◽  
Juan Li ◽  
...  

To examine whether 1 mm of spermidine (Spd) modifies plant ethylene production in response to short-term salt stress, cucumber (Cucumis sativus) seedlings were grown in nutrient solution with or without 75 mm NaCl stress for 3 days, and the leaves were sprayed with 1 mm Spd or water (control). We investigate the effects of the treatments on ethylene production, 1-aminocyclopropane-1-carboxylate (ACC) content, 1-(malonylamino) cycolpvopane-1-carboxylic acid (MACC) content, activities of 1-aminocyclopropane-1-carboxylate synthase (ACS), and 1-aminocyclopropane-1-carboxylate oxidase (ACO) and gene expression of acs2, aco1, and aco2 in the cucumber leaves. The results indicate that ethylene production was increased significantly under salt stress as did ACC and MACC content, the activities of ACS and ACO, and the transcriptional level of acs2, whereas the gene expression of aco1 and aco2 was somewhat decreased. However, exogenous Spd treatment depressed the content of ACC and MACC, ACS activity, and the level of acs2 transcripts in the leaves of salt-stressed cucumber. Although the activity of ACO and gene expressions of aco1 and aco2 increased by Spd, ethylene emission was inhibited. Our results suggest that application of exogenous Spd could reverse salinity-induced ethylene production by inhibiting the transcription and activity of ACS under salt stress. We conclude that exogenous Spd could modify the biosynthesis of ethylene to enhance the tolerance of cucumber seedlings to salt stress.


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