Abstract text: MicroRNAs (miRNAs) are small, non-coding RNAs that play vital roles in regulating plant growth, responses to environmental stress and plant development. This project aims to elucidate the functions of specific miRNAs that fluctuate in abundance during the primary to secondary cell wall transition in Arabidopsis thaliana using reverse genomics techniques. Firstly, Loss-of-function lines generated via Cluster Regulated Interspaced Short Palindromic Repeats/ CRISPR-associated protein 9 (CRISPR/Cas9) technology and/or acquired via T-DNA insertion lines. Secondly, Overexpression mutants were generated by cloning the target gene under a strong promotor. Mutants will be validated through sanger sequencing, qRT-PCR, and mutant line genotyping. Functional genomic analyses will then compare wild-type and mutant plants, focusing on molecular differences in gene expression and cell wall composition. Phenotypic assessments will evaluate growth, stress tolerance, and structural traits associated with cell wall transitions. The broader implications of miRNA regulation in plant development and stress response will be explored, highlighting potential applications in improving crop resilience and productivity. This study provides novel insights into miRNA mediated regulation of cell wall dynamics, offering strategies for advancing agricultural sustainability.