Molecular Basis of Silicon‐Mediated Plant Defense: Transporters, Cell Wall Integrity, Redox‐Hormone Crosstalk, and Epigenetic Priming

ABSTRACT Silicon (Si) is emerging as a key modulator, and its molecular mechanism of defense regulation keeps emerging. This review focus on Si‐uptake by Lsi‐type transporters, deposition in cuticles and cell wall, redox buffering, modify cell wall integrity (CWI) and hormonal signaling to increase resistance against adverse conditions and to reshape plant‐microbe‐soil interaction in rhizosphere. By highlighting the emerging research on Si‐mediated regulations at molecular scale, we proposed two working hypotheses which are ‘mechanical buffer model’ for soluble‐Si and ‘dynamic signaling model’ for Si‐nanomaterials (Si‐NPs). Mechanical buffer model states that Si‐fortified walls could stabilize the ROS profile and wall mechanics to maintain and primed state for cell while dynamic signaling model states that Si‐NPs follow an additional vesicle‐mediated uptake forming a corona protein, elicit ROS‐bursts, robust activation of FERONIA‐like receptors, Ca 2+ channels, and JA/SA signaling. Furthermore, association of Si‐associated chromatin and siRNAs were summarized and how these Si‐mediated alterations in DNA methylation under stress conditions could support the stress memory and defense priming. Overall, this framework could provide a molecular basis for Si‐mediated inputs and breeding approaches with the aim of climate‐resilient crops.