Arsenic Uptake, Toxicity, Detoxification, and Speciation in Plants: Physiological, Biochemical, and Molecular Aspects

Abstract

Environmental contamination with arsenic (As) is a global environmental, agricultural and health issue due to the highly toxic and carcinogenic nature of As. Exposure of plants to As, even at very low concentration, can cause many morphological, physiological, and biochemical changes. The recent research on As in the soil-plant system indicates that As toxicity to plants varies with its speciation in plants (e.g., arsenite, As(III); arsenate, As(V)), with the type of plant species, and with other soil factors controlling As accumulation in plants. Various plant species have different mechanisms of As(III) or As(V) uptake, toxicity, and detoxification. This review briefly describes the sources and global extent of As contamination and As speciation in soil. We discuss different mechanisms responsible for As(III) and As(V) uptake, toxicity, and detoxification in plants, at physiological, biochemical, and molecular levels. This review highlights the importance of the As-induced generation of reactive oxygen species (ROS), as well as their damaging impacts on plants at biochemical, genetic, and molecular levels. The role of different enzymatic (superoxide dismutase, catalase, glutathione reductase, and ascorbate peroxidase) and non-enzymatic (salicylic acid, proline, phytochelatins, glutathione, nitric oxide, and phosphorous) substances under As(III/V) stress have been delineated via conceptual models showing As translocation and toxicity pathways in plant species. Significantly, this review addresses the current, albeit partially understood, emerging aspects on (i) As-induced physiological, biochemical, and genotoxic mechanisms and responses in plants and (ii) the roles of different molecules in modulation of As-induced toxicities in plants. We also provide insight on some important research gaps that need to be filled to advance our scientific understanding in this area of research on As in soil-plant systems.

Di-n-butyl phthalate-induced phytotoxicity in Hordeum vulgare seedlings and subsequent antioxidant defense response

“…Furthermore, in our previous study, the content of H2O2 was also observed to enhance in the shoots and roots of barley seedlings under DBP stress (Kumari et al 2019). The accumulation of H2O2 might be because of photorespiratory oxidation or β-oxidation induced by the exposure to DBP (Abbas et al 2018).…”

“…In wheat plants under DEHP exposure, the activity of APX increases as compared to the control (Gao et al 2018). APX catalyzes the reduction of H2O2 using ascorbate as an electron donor; it plays an important role in the mitigation of intracellular ROS content (Abbas et al 2018).…”

Proteomic studies of honeybee- and manually-collected pollen

“…15 Q10SX6) was overexpressed only in the sample from Malus sylvestris pollen. Arsenate reductase protein is required for arsenate resistance (Abbas et al, 2018). It was shown that absence of arsenic reductase in Arabidopsis results in accumulation of arsenic 10-to 16-fold more compared with wild-type plants and this can lead to toxic effects on pollen tube development (Dhankher et al, 2006).…”

Effect of arsenic on growth, lipid peroxidation and antioxidant defence system in cowpea

“…Antioxidant defence system: Under As stress, plants can induce oxidative stress, which causes an imbalance between ROS generation and ROS scavenging. (Abbas et al, 2018). Among the antioxidant enzymes, SOD is a major enzyme that constitutes the first line of defence against ROS in plants ( Abbas et al, 2014).…”