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 Regulation of Ascorbate-Glutathione Pathway in Mitigating Oxidative Damage in Plants under Abiotic Stress

Antioxidants ◽  
2019 ◽  
Vol 8 (9) ◽  
pp. 384 ◽  
Author(s):  
Mirza Hasanuzzaman ◽  
M. H. M. Borhannuddin Bhuyan ◽  
Taufika Islam Anee ◽  
Khursheda Parvin ◽  
Kamrun Nahar ◽  
...  
Keyword(s):  
Abiotic Stress ◽  
Defense Mechanisms ◽  
Antioxidant Defense ◽  
Antioxidant Defense System ◽  
Vital Role ◽  
Monodehydroascorbate Reductase ◽  
Ros Generation ◽  
Stressed Condition ◽  
Defense System ◽  
Adverse Conditions

Reactive oxygen species (ROS) generation is a usual phenomenon in a plant both under a normal and stressed condition. However, under unfavorable or adverse conditions, ROS production exceeds the capacity of the antioxidant defense system. Both non-enzymatic and enzymatic components of the antioxidant defense system either detoxify or scavenge ROS and mitigate their deleterious effects. The Ascorbate-Glutathione (AsA-GSH) pathway, also known as Asada–Halliwell pathway comprises of AsA, GSH, and four enzymes viz. ascorbate peroxidase, monodehydroascorbate reductase, dehydroascorbate reductase, and glutathione reductase, play a vital role in detoxifying ROS. Apart from ROS detoxification, they also interact with other defense systems in plants and protect the plants from various abiotic stress-induced damages. Several plant studies revealed that the upregulation or overexpression of AsA-GSH pathway enzymes and the enhancement of the AsA and GSH levels conferred plants better tolerance to abiotic stresses by reducing the ROS. In this review, we summarize the recent progress of the research on AsA-GSH pathway in terms of oxidative stress tolerance in plants. We also focus on the defense mechanisms as well as molecular interactions.

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 Regulation of Reactive Oxygen Species and Antioxidant Defense in Plants under Salinity

2021 ◽  
Vol 22 (17) ◽  
pp. 9326
Author(s):  
Mirza Hasanuzzaman ◽  
Md. Rakib Hossain Raihan ◽  
Abdul Awal Chowdhury Masud ◽  
Khussboo Rahman ◽  
Farzana Nowroz ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Reactive Oxygen Species ◽  
Salt Stress ◽  
Oxidative Damage ◽  
Antioxidant Defense ◽  
Reactive Oxygen ◽  
Antioxidant Defense System ◽  
Ros Generation ◽  
Oxygen Species ◽  
Defense System

The generation of oxygen radicals and their derivatives, known as reactive oxygen species, (ROS) is a part of the signaling process in higher plants at lower concentrations, but at higher concentrations, those ROS cause oxidative stress. Salinity-induced osmotic stress and ionic stress trigger the overproduction of ROS and, ultimately, result in oxidative damage to cell organelles and membrane components, and at severe levels, they cause cell and plant death. The antioxidant defense system protects the plant from salt-induced oxidative damage by detoxifying the ROS and also by maintaining the balance of ROS generation under salt stress. Different plant hormones and genes are also associated with the signaling and antioxidant defense system to protect plants when they are exposed to salt stress. Salt-induced ROS overgeneration is one of the major reasons for hampering the morpho-physiological and biochemical activities of plants which can be largely restored through enhancing the antioxidant defense system that detoxifies ROS. In this review, we discuss the salt-induced generation of ROS, oxidative stress and antioxidant defense of plants under salinity.

scholarly journals Hydrogen Sulfide and Cellular Redox Homeostasis

2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
Zhi-Zhong Xie ◽  
Yang Liu ◽  
Jin-Song Bian
Keyword(s):  
Hydrogen Sulfide ◽  
Antioxidant Defense ◽  
Redox Homeostasis ◽  
Antioxidant Defense System ◽  
Ros Generation ◽  
Cellular Redox ◽  
Wide Range ◽  
Underlying Mechanisms ◽  
Antioxidant Effects

Intracellular redox imbalance is mainly caused by overproduction of reactive oxygen species (ROS) or weakness of the natural antioxidant defense system. It is involved in the pathophysiology of a wide array of human diseases. Hydrogen sulfide (H2S) is now recognized as the third “gasotransmitters” and proved to exert a wide range of physiological and cytoprotective functions in the biological systems. Among these functions, the role of H2S in oxidative stress has been one of the main focuses over years. However, the underlying mechanisms for the antioxidant effect of H2S are still poorly comprehended. This review presents an overview of the current understanding of H2S specially focusing on the new understanding and mechanisms of the antioxidant effects of H2S based on recent reports. Both inhibition of ROS generation and stimulation of antioxidants are discussed. H2S-induced S-sulfhydration of key proteins (e.g., p66Shc and Keap1) is also one of the focuses of this review.

scholarly journals Beneficial Effects of Exogenous Melatonin on Overcoming Salt Stress in Sugar Beets (Beta vulgaris L.)

Plants ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 886
Author(s):  
Pengfei Zhang ◽  
Lei Liu ◽  
Xin Wang ◽  
Ziyang Wang ◽  
He Zhang ◽  
...  
Keyword(s):  
Salt Stress ◽  
Antioxidant Defense ◽  
Sugar Content ◽  
Soluble Sugar ◽  
Membrane Integrity ◽  
Antioxidant Defense System ◽  
Defense System ◽  
Sugar Beets ◽  
Ps Ii ◽  
Positive Effects

Melatonin has been regarded as a promising substance that enhances the abiotic stress tolerance of plants. However, few studies have devoted attention to the role of melatonin in improving salt tolerance in sugar beets. Here, the effects of different application methods (foliar application (100 μM), root application (100 μM), and combined foliar and root application) of melatonin on the morphological and physiological traits of sugar beets exposed to salt stress were investigated. The results showed that melatonin improved the growth of sugar beet seedlings, root yield and sugar content, synthesis of chlorophyll, photosystem II (PS II) activity, and gas exchange parameters under salt stress conditions. Moreover, melatonin enhanced the capacity of osmotic adjustment by increasing the accumulation of osmolytes (betaine, proline, and soluble sugar). At the same time, melatonin increased the H+-pump activities in the roots, thus promoting Na+ efflux and K+ influx, which maintained K+/Na+ homeostasis and mitigated Na+ toxicity. In addition, melatonin strengthened the antioxidant defense system by enhancing the activities of antioxidant enzymes, modulating the ASA-GSH cycle, and mediating the phenylalanine pathway, which removed superoxide anions (O2•−) and hydrogen peroxide (H2O2) and maintained cell membrane integrity. These positive effects were more pronounced when melatonin was applied by combined foliar and root application. To summarize, this study clarifies the potential roles of melatonin in mitigating salt stress in sugar beets by improving photosynthesis, water status, ion homeostasis, and the antioxidant defense system.

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