Abiotic Stress and Reactive Oxygen Species: Generation, Signaling, and Defense Mechanisms

Abstract

Climate change is an invisible, silent killer with calamitous effects on living organisms. As the sessile organism, plants experience a diverse array of abiotic stresses during ontogenesis. The relentless climatic changes amplify the intensity and duration of stresses, making plants dwindle to survive. Plants convert 1–2% of consumed oxygen into reactive oxygen species (ROS), in particular, singlet oxygen (1O2), superoxide radical (O2•–), hydrogen peroxide (H2O2), hydroxyl radical (•OH), etc. as a byproduct of aerobic metabolism in different cell organelles such as chloroplast, mitochondria, etc. The regulatory network comprising enzymatic and non-enzymatic antioxidant systems tends to keep the magnitude of ROS within plant cells to a non-damaging level. However, under stress conditions, the production rate of ROS increases exponentially, exceeding the potential of antioxidant scavengers instigating oxidative burst, which affects biomolecules and disturbs cellular redox homeostasis. ROS are similar to a double-edged sword; and, when present below the threshold level, mediate redox signaling pathways that actuate plant growth, development, and acclimatization against stresses. The production of ROS in plant cells displays both detrimental and beneficial effects. However, exact pathways of ROS mediated stress alleviation are yet to be fully elucidated. Therefore, the review deposits information about the status of known sites of production, signaling mechanisms/pathways, effects, and management of ROS within plant cells under stress. In addition, the role played by advancement in modern techniques such as molecular priming, systems biology, phenomics, and crop modeling in preventing oxidative stress, as well as diverting ROS into signaling pathways has been canvassed.

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

“…Reactive oxygen species produced in plants are composed of both free radicals and non-radicals [2,13]. The common cellular ROS radicals are O 2…”

“…Due to disruption of the equilibrium between ROS production and antioxidant defense, oxidative stress occurs under abiotic stresses (including salinity). Non-enzymatic as well as enzymatic components of the antioxidant defense system scavenge or detoxify the excessive ROS which mitigates the negative effect of oxidative stress [2,13]. The most investigated major components of the antioxidant defense system are superoxide dismutase (SOD), peroxidase (POD/POX), catalase (CAT), the ascorbate-glutathione (AsA-GSH) cycle enzymes (ascorbate peroxidase, APX; monodehydroascorbate reductase, MDHAR; dehydroascorbate reductase, DHAR; glutathione reductase, GR), peroxiredoxins (PRX), glutathione peroxidases (GPX) and glutathione S-transferases (GST), which act in reducing ROS under abiotic stress including salt stress [2,14].…”

Molybdenum-Induced Regulation of Antioxidant Defense-Mitigated Cadmium Stress in Aromatic Rice and Improved Crop Growth, Yield, and Quality Traits

“…Generally, ROS is scavenged by antioxidant enzymes. For example, SOD catalyzes O 2 - into H 2 O 2 , and then H 2 O 2 is disintegrated by CAT and APX [ 42 , 45 , 46 ]. Previous studies also reported that Mo supply relieved oxidative damage by improving the antioxidant defense ability of plants under cold, drought, salt stress, and heavy metals [ 11 , 13 , 47 ].…”

Measuring ROS and redox markers in plant cells

“…99,100 Using such dimedone probes together with mass spectrometry has enabled identification of 226 sulfenylated proteins in H 2 O 2 -treated Arabidopsis cells 100 and 11 sulfenylated proteins in H 2 O 2 -stressed Arabidopsis seedlings. 101 While these probes could detect overall levels of SOH in plant cells, the identification of the site of modified cysteines became possible with the use of a more reactive SOH reactive probe, BTD (1-(pent-4-yn-1-yl)-1H-benzo[c] [1,2]thiazin-4(3H)one 2,2-dioxide) with a 'clickable' handle for biotinylation of labelled fragments (Fig. 4B).…”