MicroRNA-mediated regulation of cell wall dynamics and intercellular communication under stress.

MicroRNAs (miRNAs) are short endogenous non-coding RNAs that regulate gene expression at the post-transcriptional level through mRNA cleavage or translational repression. In plants, miRNAs play pivotal roles in a wide range of biological processes, including development, growth, and responses to biotic and abiotic stresses. Central to these processes is the plant cell wall, a dynamic structure that not only provides mechanical support but also functions as the first line of defense against environmental challenges and pathogen attack. The plant cell wall must maintain a fine balance between rigidity and plasticity, enabling rapid remodeling in response to developmental cues and stress signals. This remodeling process requires tight and coordinated regulation of genes involved in cell wall biosynthesis, modification, and degradation. Emerging evidence indicates that miRNAs are key regulators of these processes, modulating the expression of transcription factors, enzymes, and signaling components associated with cell wall dynamics. In addition to their intracellular roles, miRNAs can also function as mobile signals, linking cell wall remodeling with intercellular communication through plasmodesmata and coordinating responses at the tissue level. Furthermore, recent studies suggest that pathogen-derived small RNAs may contribute an additional regulatory layer by targeting host genes associated with cell wall structure and connectivity. In this review, we summarize recent advances in the identification and functional characterization of miRNAs involved in the regulation of plant cell wall responses. We highlight their regulatory implications, target genes, and roles in integrating developmental, stress-related, and intercellular communication pathways. Understanding the RNA-mediated control of cell wall dynamics provides new insights into plant adaptability and resilience, with potential applications in crop improvement and stress tolerance engineering.