Dynamic role of iron supply in amelioration of cadmium stress in mungbean

Although iron (Fe) is abundant in the earth’s crust, it is largely unavailable for plants, especially those growing in alkaline and calcareous soils. Higher plants such as graminaceous plants and dicots acquire iron in the form of phytosiderophores, which solubilize ferric Fe in the rhizosphere. When Fe uptake is very low in plants, they often accumulate toxic metals in their roots, such as cadmium (Cd), which can affect growth and development. Cadmium induces oxidative stress in plant tissue by generating reactive oxygen species, including hydrogen peroxide and singlet oxygen. Although several studies have reported the effect of Fe levels on Cd toxicity in Strategy I plants (all plants except graminaceous monocots) based on the response to iron shortage, little is known about the response to Cd toxicity in Fe-deficient leguminous plants.

role of iron supply in amelioration of cadmium stress
Diagrammatic representation of the present study for the transport of iron, and mungbean affected by four Fe/Cd combined treatments: adequate Fe with −Cd (+Fe/−Cd, control), Fe-deficient with Cd stress (−Fe/+Cd), Fe-deficient but −Cd (−Fe/−Cd) and adequate Fe with Cd stress (+Fe/+Cd) days. The diagram represents how iron is transported to plants and how combined treatments of iron and cadmium interact with each other. Overall, the representation is about how iron helps mungbean to mitigate/alleviate ROS produced in response to cadmium stress. Image credit: Biyani et al.

A recent study conducted by Biyani et al. and published in AoBP was performed on mungbean (Vigna radiata) to determine the effects of treatment with Cd and Fe on redox reactions. The activities of antioxidative enzymes (superoxide dismutase, catalase, and glutathione reductase and ascorbate peroxidase) were decreased 10 days after Fe-Cd treatment but increased following Fe supplementation. A reduction in concentrations of peroxidase enzymes was observed 10 days after Fe-Cd treatment but levels were also increased by Fe supplementation. The data indicate that supply of Fe contributes to the alleviation of Cd toxicity in redox reaction pathways in mungbean plants.