Reactive oxygen species and antioxidant machinery in abiotic stress tolerance in crop plants

The contamination of soils and water with metals has created a major environmental problem, leading to considerable losses in plant productivity and hazardous health effects. Exposure to toxic metals can intensify the production of reactive oxygen species (ROS), which are continuously produced in both unstressed and stressed plants cells. Some of the ROS species are highly toxic and must be detoxified by cellular stress responses, if the plant is to survive and grow. The aim of this review is to assess the mode of action and role of antioxidants in protecting plants from stress caused by the presence of heavy metals in the environment.

Making the life of heavy metal-stressed plants a little easier

Global climate change and associated adverse abiotic stress conditions, such as drought, salinity, heavy metals, waterlogging, extreme temperatures, oxygen deprivation, etc., greatly influence plant growth and development, ultimately affecting crop yield and quality, as well as agricultural sustainability in general. Plant cells produce oxygen radicals and their derivatives, so-called reactive oxygen species (ROS), during various processes associated with abiotic stress. Moreover, the generation of ROS is a fundamental process in higher plants and employs to transmit cellular signaling information in response to the changing environmental conditions. One of the most crucial consequences of abiotic stress is the disturbance of the equilibrium between the generation of ROS and antioxidant defense systems triggering the excessive accumulation of ROS and inducing oxidative stress in plants. Notably, the equilibrium between the detoxification and generation of ROS is maintained by both enzymatic and nonenzymatic antioxidant defense systems under harsh environmental stresses. Although this field of research has attracted massive interest, it largely remains unexplored, and our understanding of ROS signaling remains poorly understood. In this review, we have documented the recent advancement illustrating the harmful effects of ROS, antioxidant defense system involved in ROS detoxification under different abiotic stresses, and molecular cross-talk with other important signal molecules such as reactive nitrogen, sulfur, and carbonyl species. In addition, state-of-the-art molecular approaches of ROS-mediated improvement in plant antioxidant defense during the acclimation process against abiotic stresses have also been discussed.

Reactive Oxygen Species and Antioxidant Defense in Plants under Abiotic Stress: Revisiting the Crucial Role of a Universal Defense Regulator

Unravelling cadmium toxicity and tolerance in plants: Insight into regulatory mechanisms

https://www.cell.com/trends/biotechnology/pdf/S0167-7799(09)00223-6.pdf

Potential of siderophore-producing bacteria for improving heavy metal phytoextraction

Although many questions concerning reactive oxygen species metabolism and cadmium (Cd) have not been answered, the rapid progress of proteomics and metabolomics, and their interactions, may be important tools in helping to define these roles more clearly in the near future. In addition, metabolomics can provide biochemical and physiological knowledge about network organizations in plants subjected to Cd stress. Understanding these processes may considerably increase our knowledge of Cd phytotoxicity and induced oxidative stress. Such information, complemented by using mutants, genetic engineering, and the development of cellular markers, will allow the manipulation of cellular redox status and identify traits for plant tolerance programs.

Novel Technologies for Developing Cadmium Tolerance

Background Sunscald is a physiological disorder that occurs in many horticultural products when exposed to excessive solar radiation and high temperatures. Traditionally, sunscald is controlled using physical barriers that reflect radiation, however this practice is not always efficient. A possible alternative would be the use of chemical barriers, such as mycosporine-like amino acids (MAAs), which protect aquatic organisms against ultraviolet (UV) radiation. Thus, this study aimed to develop a lipid-based emulsion containing MAAs for using in the preharvest of horticultural products. Results Emulsions were developed using 10% (w/v) of corn oil (CO) and soybean oil (SO), carnauba wax (CW), and beeswax (BW) as lipid bases (LBs). The emulsion containing CW and ammonium hydroxide was the most stable, resembling commercial wax. Therefore, this formulation was used as the basis for the incorporation of the commercial product Helioguard™ 365, a source of MAA, in concentrations of 0%, 1%, 2%, and 4% (v/v). The MAA incorporation resulted in little modifications in the stability of the emulsion, providing an increase in the absorbance with peaks in the UV-B ranging from 280 to 300 nm. Conclusion The lipid-base emulsion containing MAAs could be used as a chemical barrier to control sunscald in horticultural products. © 2021 Society of Chemical Industry.

Production of mycosporine-like amino acid (MAA)-loaded emulsions as chemical barriers to control sunscald in fruits and vegetables

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How does water deficit induce changes in primary and secondary metabolism in Corymbia citriodora seedlings?

Effect of Lipid-Based Coatings Containing Mycosporine-Like Amino Acids (Maa) on Sunscald Control and Orange Fruit Quality and Composition

BACKGROUND
Soybean is widely cultivated around the world, including regions with salinity conditions. Salt stress impairs plant physiology and growth, but recent evidence suggests that silicon (Si) is able to mitigate this stressful condition. Therefore, the purpose of this study was to evaluate how different strategies of Si application impact on salt stress tolerance of an intermediate-Si-accumulator species (soybean). Therefore, we applied four treatments: Si-untreated plants (Si 0); foliar spraying at 20 mM (Si F); nutritive solution addition at 2.0 mM (Si R), and combined foliar spraying at 20 mM plus nutritive solution at 2.0 mM (Si F + R). We investigate how Si application modified growth, leaf gas exchange, photosynthetic pigments, chlorophyll fluorescence, relative water content (RWC), nutrients accumulation, and ion homeostasis of soybean plants submitted to different levels of salt stress (50 and 100 mM of NaCl).


RESULTS
Salinity induced an expressive reduction in ion accumulation, plant water status, and growth of soybean, whilst Si application promoted contrary effects and increased potassium (K+ ) accumulation, water status, photosynthetic pigments content, chlorophyll fluorescence parameters, and gas exchange attributes. Additionally, Si application enhanced Si accumulation associated with decreased Na+ uptake and improved morpho-physiological growth.


CONCLUSION
The use of exogenous Si can be an efficient strategy to attenuate the harmful effects of salt stress in soybean plants. The best application method was observed with the combined foliar spraying with the presence of Si in the nutritive solution (Si F + R) strategy. This article is protected by copyright. All rights reserved.

Priscila Lupino Gratão

Papers

Novel Technologies for Developing Cadmium Tolerance

Production of mycosporine-like amino acid (MAA)-loaded emulsions as chemical barriers to control sunscald in fruits and vegetables

How does water deficit induce changes in primary and secondary metabolism in Corymbia citriodora seedlings?

Effect of Lipid-Based Coatings Containing Mycosporine-Like Amino Acids (Maa) on Sunscald Control and Orange Fruit Quality and Composition

Silicon mitigates the negative impacts of salt stress in soybean plants.