Arsenic-Induced Stress and Mitigation Strategies in Plants

Abstract

Arsenic (As) is a toxic metalloid and inorganic arsenic is carcinogenic to humans and animals. About 50 ppb (µg/L) has been the standard for arsenic in drinking water in the USA since 1942. In the 1960s, published data from Taiwan indicated that arsenic in drinking water could cause skin cancer. In 2001, USEPA reduced the limit from 50 to 10 µg/L. According to WHO, the newly recommended guideline value for drinking water is 10 µg/L (Australia 7 µg/L). Arsenic enters in the plant system via contaminated irrigation water or soil. The toxic effect of arsenic in plants causes many metabolic disorders and often leads to death of the plants. Plants are equipped with multilayer defense weapons to encounter arsenic toxicity inside the system. Arsenic is analogous to phosphate and competes with phosphate molecules at transporter site. Once it enters in the plant cell, phytochelatins are ready for sequestration and accumulation of arsenic in vacuoles. Plants have enzymatic and nonenzymatic defense systems for arsenic-mediated oxidative damage. The chapter presents the latest research and findings for interaction between plant cell and arsenic.