Speciation, Mobilization, and Toxicity of Cadmium in Soil–Microbe–Plant System: An Overview

The extensive application of cadmium (Cd) in various industrial products results in worldwide contamination. In the first part of this chapter, we mainly focus on cadmium species, mobility, and factors influencing Cd bioavailability in soils. Furthermore, as Cd interacts with essential cellular components adversely affecting microbial biomass and diversity, we also report various sophisticated resistance mechanisms that provide microorganisms tolerance to Cd. Additionally, attention is paid to highlighting rhizodegradation as an interface between microbes and the rhizosphere that can significantly influence the increase of nutrient uptake and decline of metal toxicity. In particular, we further discuss cadmium accumulation, toxicity, and defense mechanisms in plants against Cd toxicity.