Silicon induces phytochelatin and ROS scavengers facilitating cadmium detoxification in rice.

Abstract

•Cadmium (Cd) is detrimental to crops and the environment. This work examines the natural mechanisms underlying Si-directed Cd detoxification in rice plants. •The addition of Si under Cd stress demonstrated significant improvement in morphological parameters, chlorophyll score, Fv/Fm (maximum potential quantum efficiency of photosystem II) and total soluble protein concentration compared to controls, confirming that Si is able to withstand Cd-induced damages in rice plants. This morpho-physiological evidence was correlated with decreased cell death and electrolyte leakage due to Si application. •Results demonstrated no critical changes in root Cd concentration, while the shoot Cd decreased significantly after Si supplementation in comparison with Cd-stressed rice. Additionally, expression of Cd transporters (OsNRAMP5 and OsHMA2) significantly downregulated while the concentration of phytochelatin, cysteine, and glutathione along with the expression of OsPCS1 (phytochelatin synthase) significantly induced subjected to Si treatment in roots of Cd-stressed rice. This confirms that the alleviation of Cd is not only limited to the downregulation of Cd transporters but also closely related to the PC-driven vacuolar storage of Cd in rice roots. •The enzymatic analysis further revealed the role of SOD and GR enzymes to protect rice plants from Cd-induced oxidative harm. These findings suggest the mechanistic basis in rice plants for Si - mediated mitigation of Cd stress.