Defense Responses in Cereal Crops Against Cadmium Toxicity: An Overview

Heavy metal cadmium (Cd) is hazardous and naturally occurs in the environment. It is also produced by various anthropogenic activities and is a contaminant. Since food is the primary source of Cd consumption for the non-smoking population, soil pollution has an impact on human health. Cd poisoning in crops can be caused by disruptions in the uptake and transport of mineral nutrients and disruptions in plant metabolism, which can impede plant development and evolution. Nonetheless, plants possess ways to withstand Cd, such as limited absorption of cadmium, reduced translocation from the root to the shoot, heightened activity of antioxidant enzymes and elevated phytochelatin synthesis. There are various molecular, biochemical, metabolic, genetic and exogenous factors that crops can employ to mitigate either the uptake of Cd or enhance their tolerance levels during severe Cd stress. In this chapter, we have intricately discussed the toxic effects of Cd on some of the most staple cereal crops prevalent in Indian subcontinent and other parts of Asia, as well as the different types of mitigation strategies used by them and from outside sources (exogenous agents), including the examples of natural hyperaccumulators used extensively for bioremediation purposes. The ecological significance of Cd stress in multidisciplinary research and crucial remediation techniques to address Cd contamination in agricultural soil will be addressed in this chapter.