The emerging insights on signaling molecule-mediated hyperaccumulation: Unlocking potential in metal-stressed plants...

Phytoremediation, which involves plants and their associated microbiome, is a sustainable remediation strategy for removing, stabilizing, or degrading contaminants in the ecosystem. The technology revolves around hyperaccumulators that tolerate and remove contaminants through their physiological and molecular mechanisms that are facilitated by various signaling molecules [reactive oxygen species (ROS), phytohormones, calcium ions (Ca²⁺), nitric oxide (NO), and electrophysiological signals]. This review aims to define the phenomenon of phytoremediation, enumerate its types, and highlight its limitations, with an emphasis on the role of hyperaccumulator plants in environmental remediation. The major focus is on the signaling molecules-regulated molecular mechanisms of metal uptake, translocation, chelation, sequestration, and antioxidant defence. Remediation processes are optimized by regulatory networks resulting from phytohormonal cross-talk. The transgenic and CRISPR/Cas9 technologies can significantly improve the hyperaccumulator capacity through gene overexpression and gene editing of those encoding the biosynthesis of signaling molecules. The processes, phytostabilization, phytoextraction, and the microbial breakdown of organic pollutants by plants, have shown the most removal of contaminants in the in-situ experiments. The research gaps are the complexity of the pathway, the variability of the environment, and a detailed research plan, focusing on electrophysiology and the integration of Artificial intelligence/Machine learning. The concept of coupling microbial synergy, nanotechnology, and portable monitoring can accomplish the phytoremediation shift from the lab to the field. Signaling molecules can be utilized by hyperaccumulators to effectively address the global problem of contamination, thereby enabling the development of renewable and environmentally friendly solutions for the eco-restoration of contaminated sites.