Antioxidant Defence: A Key Mechanism of Chromium Tolerance

Abstract

Abiotic stresses, which include high salt accumulation, drought, high temperature, heavy metal stress, light, lack of nutrients, radiation, and many others, pose a constant threat to plants living in an environment that is in a state of constant change. The productivity, as well as the quality of the crops, may be significantly reduced as a result of such stresses. It has been established that Cr is a human carcinogen that can enter the body of a person either through inhalation or the consumption of food products that are contaminated with Cr. Due to the hazardous consequences of the deposition of chromium in the environment, as well as the hazards that the metal may produce, both the Agency for Toxic Substances and Disease Registry and the United States Environmental Protection Agency categorize chromium as a major contaminant. As Cr is found in nature in several valence states, such as Cr3+ and Cr6+, it is possible to find it in several different valence states. Chromium (Cr) is a heavy metal that is known to produce reactive oxygen species (ROS), which are especially harmful to vegetation and need to be controlled to safeguard species against osmotic damage caused by high concentrations of Cr. One of the most dangerous and enduring types of Cr in the soil is Cr6+. Reactive oxygen species (ROS), which are produced as a result of Chromium, as well as some cellular and metabolic processes can be disrupted. Researchers who study plant genetics and transcriptional control have discovered that when plants are under Cr stress, various genes involved in detoxification are up-regulated, which confers tolerance on the plants. The higher production of reactive oxygen species (ROS) is an important indicator of the presence of such stresses at the molecular level. ROS are highly reactive in their natural state because they can interact with many different molecules and metabolites found within cells, which can ultimately result in irreversible metabolic dysfunction and death. As ROS were produced and scavenged in various structures of plant cells, the ROS-scavenging routes that arise from the various components of plant cells can also be integrated with the ROS-producing routes that are found in plant cells. New research on plants has demonstrated that extremely small concentrations of ROS may serve as chemical messengers and raise a plant’s sensitivity to abiotic and biotic stresses by regulating the activities of protective genes. Several studies have also demonstrated that plants with higher antioxidant levels, whether these antioxidants are inherent or induced, are more resilient to a range of environmental challenges. This phenomenon has been observed in both wild and cultivated plants. We aim to synthesise current findings on the role of ROS in abiotic stress tolerance in this chapter as well as the possible regulatory roles that ROS may play. In addition, We go over the improvements that have been made in the last several decades in terms of enhancing plants’ ability to withstand oxidative stress through the application of genetic engineering by various ROS detoxifying systems in plants.