scholarly journals Melatonin Confers Plant Cadmium Tolerance: An Update

2021 ◽  
Vol 22 (21) ◽  
pp. 11704
Author(s):  
Quan Gu ◽  
Chuyan Wang ◽  
Qingqing Xiao ◽  
Ziping Chen ◽  
Yi Han
Keyword(s):  
Antioxidant Defense ◽  
Molecular Mechanisms ◽  
Redox Homeostasis ◽  
Antioxidant Defense System ◽  
Cd Stress ◽  
Defense System ◽  
Abiotic And Biotic Stresses ◽  
Biotic Stresses ◽  
Cd Tolerance ◽  
Complex Interactions

Cadmium (Cd) is one of the most injurious heavy metals, affecting plant growth and development. Melatonin (N-acetyl-5-methoxytryptamine) was discovered in plants in 1995, and it is since known to act as a multifunctional molecule to alleviate abiotic and biotic stresses, especially Cd stress. Endogenously triggered or exogenously applied melatonin re-establishes the redox homeostasis by the improvement of the antioxidant defense system. It can also affect the Cd transportation and sequestration by regulating the transcripts of genes related to the major metal transport system, as well as the increase in glutathione (GSH) and phytochelatins (PCs). Melatonin activates several downstream signals, such as nitric oxide (NO), hydrogen peroxide (H2O2), and salicylic acid (SA), which are required for plant Cd tolerance. Similar to the physiological functions of NO, hydrogen sulfide (H2S) is also involved in the abiotic stress-related processes in plants. Moreover, exogenous melatonin induces H2S generation in plants under salinity or heat stress. However, the involvement of H2S action in melatonin-induced Cd tolerance is still largely unknown. In this review, we summarize the progresses in various physiological and molecular mechanisms regulated by melatonin in plants under Cd stress. The complex interactions between melatonin and H2S in acquisition of Cd stress tolerance are also discussed.

scholarly journals Differences in Cadmium Accumulation, Detoxification and Antioxidant Defenses between Contrasting Maize Cultivars Implicate a Role of Superoxide Dismutase in Cd Tolerance

Antioxidants ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1812
Author(s):  
Aya Mahmoud ◽  
Hamada AbdElgawad ◽  
Badreldin A. Hamed ◽  
Gerrit T.S. Beemster ◽  
Nadia M. El-Shafey
Keyword(s):  
Superoxide Dismutase ◽  
Antioxidant Defense ◽  
Antioxidant Defense System ◽  
Antioxidant Defenses ◽  
Cd Stress ◽  
Defense System ◽  
Cd Accumulation ◽  
Cd Tolerance ◽  
Maize Cultivars

Cadmium (Cd), a readily absorbed and translocated toxic heavy metal, inhibits plant growth, interrupts metabolic homeostasis and induces oxidative damage. Responses towards Cd-stress differ among plant cultivars, and the complex integrated relationships between Cd accumulation, detoxification mechanisms and antioxidant defenses still need to be unraveled. To this end, 12 Egyptian maize cultivars were grown under Cd-stress to test their Cd-stress tolerance. Out of these cultivars, tolerant (TWC360 and TWC321), moderately sensitive (TWC324) and sensitive (SC128) cultivars were selected, and we determined their response to Cd in terms of biomass, Cd accumulation and antioxidant defense system. The reduction in biomass was highly obvious in sensitive cultivars, while TWC360 and TWC321 showed high Cd-tolerance. The cultivar TWC321 showed lower Cd uptake concurrently with an enhanced antioxidant defense system. Interestingly, TWC360 accumulated more Cd in the shoot, accompanied with increased Cd detoxification and sequestration. A principal component analysis revealed a clear separation between the sensitive and tolerant cultivars with significance of the antioxidant defenses, including superoxide dismutase (SOD). To confirm the involvement of SOD in Cd-tolerance, we studied the effect of Cd-stress on a transgenic maize line (TG) constitutively overexpressing AtFeSOD gene in comparison to its wild type (WT). Compared to their WT, the TG plants showed less Cd accumulation and improved growth, physiology, antioxidant and detoxification systems. These results demonstrate the role of SOD in determining Cd-tolerance.

scholarly journals Effect of Cadmium Toxicity on Growth, Oxidative Damage, Antioxidant Defense System and Cadmium Accumulation in Two Sorghum Cultivars

Plants ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 1575
Author(s):  
Muhammad Jawad Hassan ◽  
Muhammad Ali Raza ◽  
Sana Ur Rehman ◽  
Muhammad Ansar ◽  
Harun Gitari ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Oxidative Damage ◽  
Antioxidant Defense ◽  
Cadmium Toxicity ◽  
Antioxidant Defense System ◽  
Agricultural Crop ◽  
Cd Stress ◽  
Defense System ◽  
Cd Uptake ◽  
Semi Arid

Heavy metal stress is a leading environmental issue reducing crop growth and productivity, particularly in arid and semi-arid agro-ecological zones. Cadmium (Cd), a non-redox heavy metal, can indirectly increase the production of reactive oxygen species (ROS), inducing cell death. A pot experiment was conducted to investigate the effects of different concentrations of Cd (0, 5, 25, 50, 100 µM) on physiological and biochemical parameters in two sorghum (Sorghum bicolor L.) cultivars: JS-2002 and Chakwal Sorghum. The results showed that various concentrations of Cd significantly increased the Cd uptake in both cultivars; however, the uptake was higher in JS-2002 compared to Chakwal Sorghum in leaf, stem and root. Regardless of the cultivars, there was a higher accumulation of the Cd in roots than in shoots. The Cd stress significantly reduced the growth and increased the electrolyte leakage (EL), hydrogen peroxide (H2O2) concentration and malondialdehyde (MDA) content in both cultivars, but the Chakwal Sorghum showed more pronounced oxidative damage than the JS-2002, as reflected by higher H2O2, MDA and EL. Moreover, Cd stress, particularly 50 µM and 100 µM, decreased the activity of different antioxidant enzymes, including superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT). However, the JS-2002 exhibited higher SOD, POD and CAT activities than the Chakwal Sorghum under different Cd-levels. These findings revealed that JS-2002 had a stronger Cd enrichment capacity and also exhibited a better tolerance to Cd stress due to its efficient antioxidant defense system than Chakwal Sorghum. The present study provides the available information about Cd enrichment and tolerance in S. bicolor, which is used as an important agricultural crop for livestock feed in arid and semi-arid regions.

scholarly journals The CaCIPK3 gene positively regulates drought tolerance in pepper

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Xiao Ma ◽  
Yang Li ◽  
Wen-Xian Gai ◽  
Chuang Li ◽  
Zhen-Hui Gong
Keyword(s):  
Drought Stress ◽  
Drought Tolerance ◽  
Antioxidant Defense ◽  
Molecular Mechanisms ◽  
Ectopic Expression ◽  
Antioxidant Defense System ◽  
Pcr Analysis ◽  
Defense System ◽  
Interacting Protein ◽  
Transient Overexpression

AbstractDrought stress is a major agricultural problem restricting the growth, development, and productivity of plants. Calcineurin B-like proteins (CBLs) and CBL-interacting protein kinases (CIPKs) significantly influence the plant response to different stresses. However, the molecular mechanisms of CBL–CIPK in the drought stress response of pepper are still unknown. Here, the function of CaCIPK3 in the regulation of drought stress in pepper (Capsicum annuum L.) was explored. Transcriptomic data and quantitative real-time PCR (qRT-PCR) analysis revealed that CaCIPK3 participates in the response to multiple stresses. Knockdown of CaCIPK3 in pepper increased the sensitivity to mannitol and methyl jasmonate (MeJA). Transient overexpression of CaCIPK3 improved drought tolerance by enhancing the activities of the antioxidant system and positively regulating jasmonate (JA)-related genes. Ectopic expression of CaCIPK3 in tomato also improved drought and MeJA resistance. As the CaCIPK3-interacting partner, CaCBL2 positively influenced drought resistance. Additionally, CaWRKY1 and CaWRKY41 directly bound the CaCIPK3 promoter to influence its expression. This study shows that CaCIPK3 acts as a positive regulator in drought stress resistance via the CBL–CIPK network to regulate MeJA signaling and the antioxidant defense system.

scholarly journals Regulation of ROS Metabolism in Plants under Environmental Stress: A Review of Recent Experimental Evidence

2020 ◽  
Vol 21 (22) ◽  
pp. 8695
Author(s):  
Mirza Hasanuzzaman ◽  
M. H. M. Borhannuddin Bhuyan ◽  
Khursheda Parvin ◽  
Tasnim Farha Bhuiyan ◽  
Taufika Islam Anee ◽  
...  
Keyword(s):  
Experimental Evidence ◽  
Abiotic Stresses ◽  
Antioxidant Defense ◽  
Redox Homeostasis ◽  
Membrane Integrity ◽  
Antioxidant Defense System ◽  
Ros Generation ◽  
Growth Stages ◽  
Defense System ◽  
Ros Scavenging

Various environmental stresses singly or in combination generate excess amounts of reactive oxygen species (ROS), leading to oxidative stress and impaired redox homeostasis. Generation of ROS is the obvious outcome of abiotic stresses and is gaining importance not only for their ubiquitous generation and subsequent damaging effects in plants but also for their diversified roles in signaling cascade, affecting other biomolecules, hormones concerning growth, development, or regulation of stress tolerance. Therefore, a good balance between ROS generation and the antioxidant defense system protects photosynthetic machinery, maintains membrane integrity, and prevents damage to nucleic acids and proteins. Notably, the antioxidant defense system not only scavenges ROS but also regulates the ROS titer for signaling. A glut of studies have been executed over the last few decades to discover the pattern of ROS generation and ROS scavenging. Reports suggested a sharp threshold level of ROS for being beneficial or toxic, depending on the plant species, their growth stages, types of abiotic stresses, stress intensity, and duration. Approaches towards enhancing the antioxidant defense in plants is one of the vital areas of research for plant biologists. Therefore, in this review, we accumulated and discussed the physicochemical basis of ROS production, cellular compartment-specific ROS generation pathways, and their possible distressing effects. Moreover, the function of the antioxidant defense system for detoxification and homeostasis of ROS for maximizing defense is also discussed in light of the latest research endeavors and experimental evidence.

scholarly journals Bacillus siamensis Reduces Cadmium Accumulation and Improves Growth and Antioxidant Defense System in Two Wheat (Triticum aestivum L.) Varieties

Plants ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 878
Author(s):  
Samrah Afzal Awan ◽  
Noshin Ilyas ◽  
Imran Khan ◽  
Muhammad Ali Raza ◽  
Abd Ur Rehman ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Antioxidant Enzymes ◽  
Plant Growth ◽  
Antioxidant Defense ◽  
Antioxidant Defense System ◽  
World Population ◽  
Cd Stress ◽  
Defense System ◽  
Wheat Varieties ◽  
Cd Toxicity

Bioavailability of cadmium (Cd) metal in the soils due to the scarcity of good quality water and industrial waste could be the major limiting factor for the growth and yield of crops. Therefore, there is a need for a prompt solution to the Cd toxicity, to fulfill increasing food demand resulting from growing world population. Today, a variable range of plant growth promoting rhizobacteria (PGPR) is being used at a large scale in agriculture, to reduce the risk of abiotic stresses on plants and increase crop productivity. The objective of this study was to evaluate the efficacy of Bacillus siamensis in relieving the Cd induced damage in two wheat varieties (i.e., NARC-2009 and NARC-2011) grown in Cd spiked soil at different concentrations (0, 20, 30, 50 mg/kg). The plants under Cd stress accumulated more Cd in the roots and shoots, resulting in severe oxidative stress, evident by an increase in malondialdehyde (MDA) content. Moreover, a decrease in cell osmotic status, and alteration in antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX) were also observed in wheat plants under Cd stress. As a result, the Cd exposed plants showed a reduction in growth, tissue biomass, photosynthetic pigments, membrane stability, total soluble sugars, and amino acids, in comparison to control plants. The extent of damage was observed to be higher with an increase in Cd concentration. However, the inoculation of wheat with B. siamensis improved plant growth, reduced oxidative stress, and enhanced the activities of antioxidant enzymes in both wheat varieties. B. siamensis amendment brought a considerable improvement in every parameter determined with respect to Cd stress. The response of both wheat varieties on exposure to B. siamensis was positively enhanced, whereas NARC-2009 accumulated less Cd compared to NARC-2011, which indicated a higher tolerance to Cd stress mediated by B. siamensis inoculation. Overall, the B. siamensis reduced the Cd toxicity in wheat plants through the augmentation of the antioxidant defense system and sugars production.

scholarly journals Regulation of redox homeostasis in cadmium stressed rice field cyanobacteria by exogenous hydrogen peroxide and nitric oxide

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Nidhi Verma ◽  
Sheo Mohan Prasad
Keyword(s):  
Antioxidant Defense ◽  
Redox Homeostasis ◽  
Antioxidant Defense System ◽  
Nostoc Muscorum ◽  
Enzymatic Antioxidants ◽  
Cd Stress ◽  
Signaling Mechanism ◽  
Exogenous Application ◽  
Defensive Strategies ◽  
No Signaling

AbstractIn the present study, defensive strategies of H2O2 mediated NO signaling were analyzed in Cd stressed Nostoc muscorum and Anabaena sp. Exogenously supplied SNP (10 µM) and H2O2 (1 µM) lessen the toxicity of Cd (6 µM) but without NO; H2O2 was unable to release the stress from cyanobacterial cells potentially. The reduced contents of exopolysaccharide, protein content, endogenous NO and enzymatic antioxidants (SOD, POD, CAT, and GST) due to Cd toxicity, were found increased significantly after exogenous application of H2O2 and SNP thereafter, cyanobacterial calls flourished much better after releasing toxic level of Cd. Moreover, increased level of ROS due to Cd stress also normalized under exogenous application of H2O2 and SNP. However, chelation of NO hindered the signaling mechanism of H2O2 that diminished its potential against Cd stress while signaling of NO has not been hindered by chelation of H2O2 and NO potentially released the Cd stress from cyanobacterial cells. In conclusion, current findings demonstrated the synergistic signaling between H2O2 and NO towards the improvement of cyanobacterial tolerance to Cd stress, thereby enhancing the growth and antioxidant defense system of test cyanobacteria that improved fertility and productivity of soil even under the situation of metal contamination.

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