Solanum nigrum L.: A Novel Hyperaccumulator for the Phyto-Management of Cadmium Contaminated Soils

Abstract Cadmium (Cd) toxicity is a major threat for food security all over the world. High mobility, persistent bio-availability, and unavoidable toxicity risks, even at low concentrations, have highlighted Cd as one of the most dangerous heavy metals (HMs). However, use of Solanum nigrum ( S. nigrum ) for phyto-management of Cd-contaminated soil is well documented. This chapter will explain the negative impacts of Cd toxicity and the role of S. nigrum in phyto-management of Cd-contaminated soils. S. nigrum, commonly known as black nightshade, is a perennial weed with a fast-growing nature and high biomass production, and bulk Cd accumulation in its various tissues characterizes it as a Cd hyperaccumulator plant. S. nigrum possesses some unique characteristics, such as release of organic acids, activation of natural resistance-associated macrophage proteins (NRAMPs), and use of the antioxidant defense mechanism for phyto-management of Cd. Therefore, S. nigrum restricts Cd entry into the food chain by binding Cd into its nonactive parts, coupled with Cd complexation and/or stabilization into the rhizosphere with the release of root exudates. However, use of some additional strategies, such as farming practices, growth activators, soil amendments, and transgenic aid accelerates the S. nigrum -based Cd phyto-management technique significantly. At the moment, long-term field trials are required for testing the effectiveness and economic viability of this proximal technique for decontamination of Cd-contaminated soils on a sustainable basis.