Arsenic-Induced Oxidative Stress in Plants

Abstract

Oxidative stress is a common phenomenon in organisms that are exposed to arsenic (As), as well as many other abiotic or biotic stresses. This chapter describes the influence of As on the production of individual reactive oxygen species (ROS) in various pathways of a plant cell. Inorganic As(V) disrupts the phosphorylation metabolism, interfering with, inter alia, the flow of cellular energy. During As(V) to As(III) reduction, the electron leakage leads to ROS formation, and the accompanying redox-driven methylation contributes further to more ROS generation. Inorganic As(III) reacts with sulfhydryl groups of proteins, glutathione (GSH), and phytochelatins, affecting several important cellular functions including those related to the oxidative stress. The description of As toxicity includes the As-induced ROS reactions with macromolecules: lipid peroxidation and protein and nucleic acid damage. Some cellular processes are affected by As, e.g., As-induced ROS are involved in the activation of MAPK signaling cascades resulting in targeting transcription factors and the gene expression. Redox imbalances influence the enzymatic antioxidant system and mobilize the cell to synthesize low-molecular-weight antioxidants which are important in the prevention of ROS-induced damage. Other metabolic consequences of As-induced oxygen stress in the plant cell are also described in the chapter.