Cadmium toxicity: its' uptake and retaliation by plant defence system and ja signaling

Abstract

Cadmium (Cd⁺²) renders multifarious environmental stresses and highly toxic to nearly all living organisms including plants. Cd causes toxicity by unnecessary augmentation of ROS that targets essential molecules and fundamental processes in plants. In response, plants outfitted a repertory of mechanisms to offset Cd toxicity. The main elements of these are Cd chelation, sequestration into vacuoles, and adjustment of Cd uptake by transporters and escalation of antioxidative mechanism. Signal molecules like phytohormones and reactive oxygen species (ROS) activate the MAPK cascade, the activation of the antioxidant system andsynergistic crosstalk between different signal molecules in order to regulate plant responses to Cd toxicity. Transcription factors like WRKY, MYB, bHLH, bZIP, ERF, NAC etc., located downstream of MAPK, and are key factors in regulating Cd toxicity responses in plants. Apart from this, MAPK and Ca²⁺signaling also have a salient involvement in rectifying Cd stress in plants. This review highlighted the mechanism of Cd uptake, translocation, detoxification and the key role of defense system, MAPKs, Ca²⁺ signals and jasmonic acid in retaliating Cd toxicity via synchronous management of various other regulators and signaling components involved under stress condition.

Keywords: Ca2+ signaling; Cadmium; Jasmonates; MAPK; ROS.