Plant resilience to abiotic stresses: Reveling the role of silicon in drought and metal(loid) tolerance.

Climate change has intensified abiotic stresses in agriculture, with drought and metal toxicity being major factors, posing a significant threat to global food security. Silicon (Si), a tetravalent metalloid, emerges as a crucial element in enhancing plant resilience against abiotic stresses through its multifaceted roles at different levels in plants. Multiple studies have demonstrated Si's beneficial effects on improving water relations, nutrient uptake, structural integrity of the cell wall, mitigation of metal(loid) toxicity, and enhancement of antioxidant activity. At the molecular level, Si regulates stress-responsive genes, modulates transcription factors such as DREB2A and NAC, and promotes enzymatic pathways involved in ROS scavenging, underscoring its pivotal role in plant stress adaptation. This review provides an integrated overview of Si uptake, transport, and deposition, highlighting its physiological and molecular mechanisms in water stress adaptation, root morphology, and detoxification of metal(loid) in plant tissues. Furthermore, Si's ability to induce the expression of antioxidant enzymes and regulate transcriptional networks associated with osmotic and oxidative stress provides plants with a robust molecular framework for resilience. Here we highlight the potential of Si as a central tool for sustainable agriculture, particularly under abiotic stress conditions such as drought and metal(loid) toxicity.