Changes in enzymatic and nonenzymatic antioxidant defense mechanisms of canola seedlings at different drought stress and nitrogen levels

In recent years, research on spermine (Spm) has turned up a lot of new information about this essential polyamine, especially as it is able to counteract damage from abiotic stresses. Spm has been shown to protect plants from a variety of environmental insults, but whether it can prevent the adverse effects of drought has not yet been reported. Drought stress increases endogenous Spm in plants and exogenous application of Spm improves the plants’ ability to tolerate drought stress. Spm’s role in enhancing antioxidant defense mechanisms, glyoxalase systems, methylglyoxal (MG) detoxification, and creating tolerance for drought-induced oxidative stress is well documented in plants. However, the influences of enzyme activity and osmoregulation on Spm biosynthesis and metabolism are variable. Spm interacts with other molecules like nitric oxide (NO) and phytohormones such as abscisic acid, salicylic acid, brassinosteroids, and ethylene, to coordinate the reactions necessary for developing drought tolerance. This review focuses on the role of Spm in plants under severe drought stress. We have proposed models to explain how Spm interacts with existing defense mechanisms in plants to improve drought tolerance.

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Combined application of zinc and silicon alleviates terminal drought stress in wheat by triggering morpho-physiological and antioxidants defense mechanisms

PLoS ONE ◽

10.1371/journal.pone.0256984 ◽

2021 ◽

Vol 16 (10) ◽

pp. e0256984

Author(s):

Abdul Sattar ◽

Xiukang Wang ◽

Tahira Abbas ◽

Ahmad Sher ◽

Muhammad Ijaz ◽

...

Keyword(s):

Drought Stress ◽

Defense Mechanisms ◽

Antioxidant Defense ◽

Defense Mechanism ◽

Foliar Application ◽

Soluble Proteins ◽

Regulatory Pathways ◽

Combined Application ◽

Terminal Drought ◽

Terminal Drought Stress

Wheat is an important global staple food crop; however, its productivity is severely hampered by changing climate. Erratic rain patterns cause terminal drought stress, which affect reproductive development and crop yield. This study investigates the potential and zinc (Zn) and silicon (Si) to ameliorate terminal drought stress in wheat and associated mechanisms. Two different drought stress levels, i.e., control [80% water holding capacity (WHC) was maintained] and terminal drought stress (40% WHC maintained from BBCH growth stage 49 to 83) combined with five foliar-applied Zn-Si combinations (i.e., control, water spray, 4 mM Zn, 40 mM Si, 4 mM Zn + 40 mM Si applied 7 days after the initiation of drought stress). Results revealed that application of Zn and Si improved chlorophyll and relative water contents under well-watered conditions and terminal drought stress. Foliar application of Si and Zn had significant effect on antioxidant defense mechanism, proline and soluble protein, which showed that application of Si and Zn ameliorated the effects of terminal drought stress mainly by regulating antioxidant defense mechanism, and production of proline and soluble proteins. Combined application of Zn and Si resulted in the highest improvement in growth and antioxidant defense. The application of Zn and Si improved yield and related traits, both under well-watered conditions and terminal drought stress. The highest yield and related traits were recorded for combined application of Zn and Si. For grain and biological yield differences among sole and combined Zn-Si application were statistically non-significant (p>0.05). In conclusion, combined application of Zn-Si ameliorated the adverse effects of terminal drought stress by improving yield through regulating antioxidant mechanism and production of proline and soluble proteins. Results provide valuable insights for further cross talk between Zn-Si regulatory pathways to enhance grain biofortification.

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OsADR3 increases drought stress tolerance by inducing antioxidant defense mechanisms and regulating OsGPX1 in rice (Oryza sativa L.)

The Crop Journal ◽

10.1016/j.cj.2020.12.005 ◽

2021 ◽

Author(s):

Jiaming Li ◽

Minghui Zhang ◽

Luomiao Yang ◽

Xinrui Mao ◽

Jinjie Li ◽

...

Keyword(s):

Oryza Sativa ◽

Drought Stress ◽

Stress Tolerance ◽

Defense Mechanisms ◽

Antioxidant Defense ◽

Oryza Sativa L ◽

Drought Stress Tolerance

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DYNAMICS OF BARLEY FLAVONOID AND PRODUCTIVITY UNDER UF-A RADIATION

Vestnik of the Russian agricultural science ◽

10.30850/vrsn/2019/4/14-18 ◽

1970 ◽

pp. 14-18

Author(s):

L. I. Goncharova ◽

P. N. Tsygvintsev ◽

О. А. Guseva

Keyword(s):

Grain Yield ◽

Defense Mechanisms ◽

Antioxidant Defense ◽

Malonic Dialdehyde ◽

Growth Period ◽

Negative Effects ◽

Uv Spectrum ◽

Quantum Energy ◽

Dry Soil ◽

Universal Mechanism

The effect of increased UV-A radiation during the ontogeny of barley plants of the Vladimir variety in the vegetation experiment was studied. Changes in the content of malonic dialdehyde, flavonoids and grain yield were revealed. UV-A radiation as compared to UV-B radiation, has lower quantum energy and can have both positive and negative effects on plant regulatory and photosynthetic processes. One of the most damaging effects of increased levels of UV-A radiation is oxidative stress, which causes lipid peroxidation of biological membranes. The existence of a plant cell in such conditions is possible only thanks to a system of antioxidant defense mechanisms. The accumulation of phenolic compounds under the action of UV radiation is a universal mechanism of protection against photodamage, which was formed in the early stages of the evolution of photoautotrophic organisms. Flavonoids are localized in the epidermis of plant tissues and act as an internal filter. The content of flavonoids is determined by the genotype and due to ontogenetic patterns. Plants were grown in a greenhouse, in vessels containing 4.5 kg of air-dry soil. The repetition is threefold (3 vessels in each variant). Sowing density - 13 plants in each vessel. As a source of UV-A radiation used lamps Black Light BLUE company Philips. Plants were irradiated for 5 hours a day from 10 to 15 hours at 13, 25, 34, 43 and 52 stages of organogenesis. The magnitude of the daily biologically effective dose of UV-A radiation was 60.7 kJ / m2. The solar part of the UV spectrum in the vegetation experiment was absent in the greenhouse. The nature of changes in the content of flavonoids under the action of UV-A irradiation during the growing season of plants with the dynamics of the oxidative process has been established. The first maximum was observed during the vegetative growth period, the second - at the earing stage. The data obtained indicate that flavonoids have ontogenetic conditionality and perform photoprotective functions. The increase in their content under the action of UV-A radiation is accompanied by an increase in resistance to photodamage, which is confirmed by the formation of grain yield.

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The Impact of Plant Bioactive Compounds on Aging and Fertility of Diverse Organisms: A Review

Mini-Reviews in Medicinal Chemistry ◽

10.2174/1389557520666200429101942 ◽

2020 ◽

Vol 20 (13) ◽

pp. 1287-1299

Author(s):

Muhammad Akram Mohd Noordin ◽

Mahanem Mat Noor ◽

Wan Mohd Aizat

Keyword(s):

Clinical Trial ◽

Bioactive Compounds ◽

Defense Mechanisms ◽

Healthy Aging ◽

Antioxidant Defense ◽

Senior Citizens ◽

Aging Population ◽

Human Clinical Trial ◽

Fertility Reduction ◽

The Impact

It is expected that in 2050, there will be more than 20% of senior citizens aged over 60 years worldwide. Such alarming statistics require immediate attention to improve the health of the aging population. Since aging is closely related to the loss of antioxidant defense mechanisms, this situation eventually leads to numerous health problems, including fertility reduction. Furthermore, plant extracts have been used in traditional medicine as potent antioxidant sources. Although many experiments had reported the impact of various bioactive compounds on aging or fertility, there is a lack of review papers that combine both subjects. In this review, we have collected and discussed various bioactive compounds from 26 different plant species known to affect both longevity and fertility. These compounds, including phenolics and terpenes, are mostly involved in the antioxidant defense mechanisms of diverse organisms such as rats, mites, fruit flies, roundworms, and even roosters. A human clinical trial should be considered in the future to measure the effects of these bioactive compounds on human health and longevity. Ultimately, these plant-derived compounds could be developed into health supplements or potential medical drugs to ensure a healthy aging population.

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Assessment the copper-induced changes in antioxidant defense mechanisms and copper phytoremediation potential of common mullein (Verbascum thapsus L.)

Environmental Science and Pollution Research ◽

10.1007/s11356-020-11903-9 ◽

2021 ◽

Author(s):

Hamid Reza Kavousi ◽

Mohammad Rafie Karimi ◽

Mahmoud Ghorbanzadeh Neghab

Keyword(s):

Defense Mechanisms ◽

Antioxidant Defense ◽

Verbascum Thapsus ◽

Induced Changes ◽

Common Mullein

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Redox Regulation in Diazotrophic Bacteria in Interaction with Plants

Antioxidants ◽

10.3390/antiox10060880 ◽

2021 ◽

Vol 10 (6) ◽

pp. 880

Author(s):

Karine Mandon ◽

Fanny Nazaret ◽

Davoud Farajzadeh ◽

Geneviève Alloing ◽

Pierre Frendo

Keyword(s):

Defense Mechanisms ◽

Host Plants ◽

Redox Regulation ◽

Antioxidant Defense ◽

Plant Growth Promoting Bacteria ◽

Oxygen Species ◽

Diazotrophic Bacteria ◽

Number Of Microorganisms ◽

Plant Growth Promoting ◽

Growth Promoting

Plants interact with a large number of microorganisms that greatly influence their growth and health. Among the beneficial microorganisms, rhizosphere bacteria known as Plant Growth Promoting Bacteria increase plant fitness by producing compounds such as phytohormones or by carrying out symbioses that enhance nutrient acquisition. Nitrogen-fixing bacteria, either as endophytes or as endosymbionts, specifically improve the growth and development of plants by supplying them with nitrogen, a key macro-element. Survival and proliferation of these bacteria require their adaptation to the rhizosphere and host plant, which are particular ecological environments. This adaptation highly depends on bacteria response to the Reactive Oxygen Species (ROS), associated to abiotic stresses or produced by host plants, which determine the outcome of the plant-bacteria interaction. This paper reviews the different antioxidant defense mechanisms identified in diazotrophic bacteria, focusing on their involvement in coping with the changing conditions encountered during interaction with plant partners.

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Role of Selenium and Selenoproteins in Male Reproductive Function: A Review of Past and Present Evidences

Antioxidants ◽

10.3390/antiox8080268 ◽

2019 ◽

Vol 8 (8) ◽

pp. 268 ◽

Cited By ~ 18

Author(s):

Izhar Hyder Qazi ◽

Christiana Angel ◽

Haoxuan Yang ◽

Evangelos Zoidis ◽

Bo Pan ◽

...

Keyword(s):

Male Fertility ◽

Defense Mechanisms ◽

Antioxidant Defense ◽

Biological Effects ◽

Reproductive Function ◽

Vital Role ◽

Biologically Relevant ◽

Male Reproductive Function ◽

The Subject

Selenium (Se) is an important trace mineral having many essential roles at the cellular and organismal levels in animal and human health. The biological effects of Se are mainly carried out by selenoproteins (encoded by 25 genes in humans and 24 in mice). As an essential component of selenoproteins, Se performs structural and enzymic roles; in the latter context it is well known for its catalytic and antioxidative functions. Studies involving different animal models have added great value to our understanding regarding the potential implications of Se and selenoproteins in mammalian fertility and reproduction. In this review, we highlight the implications of selenoproteins in male fertility and reproduction followed by the characteristic biological functions of Se and selenoproteins associated with overall male reproductive function. It is evident from observations of past studies (both animal and human) that Se is essentially required for spermatogenesis and male fertility, presumably because of its vital role in modulation of antioxidant defense mechanisms and other essential biological pathways and redox sensitive transcription factors. However, bearing in mind the evidences from mainstream literature, it is also advisable to perform more studies focusing on the elucidation of additional roles played by the peculiar and canonical selenoproteins i.e., glutathione peroxidase 4 (GPX4) and selenoprotein P (SELENOP) in the male reproductive functions. Nevertheless, search for the elucidation of additional putative mechanisms potentially modulated by other biologically relevant selenoproteins should also be included in the scope of future studies. However, as for the implication of Se in fertility and reproduction in men, though a few clinical trials explore the effects of Se supplementation on male fertility, due to inconsistencies in the recruitment of subjects and heterogeneity of designs, the comparison of such studies is still complicated and less clear. Therefore, further research focused on the roles of Se and selenoproteins is awaited for validating the evidences at hand and outlining any therapeutic schemes intended for improving male fertility. As such, new dimensions could be added to the subject of male fertility and Se supplementation.

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

Antioxidants ◽

10.3390/antiox8090384 ◽

2019 ◽

Vol 8 (9) ◽

pp. 384 ◽

Cited By ~ 60

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.

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