Molecular basis of microRNA stability and degradation in plants

MicroRNAs (miRNAs) are a class of endogenous small non-coding RNAs with 20 to 24 nucleotides in length. They primarily regulate gene expression at the post-transcriptional level and influence numerous biological processes, including reproduction, development, and responses to environmental stimuli in both plants and animals. The spatiotemporal expression of miRNAs across organs, tissues, and cells is tightly regulated at multiple levels, encompassing transcription, processing, stability control, and targeted degradation. The biochemical pathway of miRNA biogenesis, including transcription and processing, has been established, and its regulatory mechanisms have also been extensively studied. In this review, we systematically summarize current advances in post-biogenesis regulation of miRNA stability, turnover, and targeted degradation in plants, with comparative analyses of similarities and differences in animal systems. By integrating these advances, this review seeks to provide a framework for further elucidating the molecular mechanisms controlling intracellular miRNA abundance.