Exploring the transporters and mechanisms of arsenic detoxification in plants and potential role of nanoparticles in alleviating arsenic stress

Current research studies on arsenic in the plant and soil system reveal that arsenic toxicity to plant species is strongly influenced by many factors including its nature (organic or inorganic), speciation (i.e. As (V); arsenite, arsenate, As (III)), solubility, concentration, the type of plant species, and other soil variables affecting arsenic bioaccumulation in plants. Therefore, As (V) or As (III) toxicity, uptake, and detoxification vary among plant species. Herein, the origins and spread of As pollution and As speciation in soil are briefly examined. Further, the numerous physiological and molecular mechanisms contributing to As(V) and As(III) toxicity, absorption, and detoxification processes in plants are investigated in detail. The role of several enzymatic (glutathione reductase, ascorbate peroxidase superoxide dismutase, and catalase) and non-enzymatic (phosphorus, phytochelatins, proline, glutathione, salicylic acid, and nitric oxide) substances under As (V/III) stress have been explained using a theoretical framework that illustrates the toxicity and translocation pathways of this metalloid in plants. This review focuses on two main topics: (i) the role of different molecules in modifying As-induced toxicities in plants and (ii) the role of nanoparticles in reducing As stress in plants. Significant research gaps that need to be addressed in order to improve our scientific knowledge of As in soil-plant systems are also highlighted.