Abstract
RNA silencing is an evolutionarily conserved mechanism in eukaryotes that control gene expression through small RNA-guided RNA degradation, translational repression and DNA methylation. Plants have evolved multiple small RNA pathways that have been demonstrated to play an essential role in developmental regulation and defence against invasive nucleic acids such as transposable elements and viruses. Recent studies have provided evidence that the different small RNA pathways play a more diverse role in plant defence against biotic and abiotic stresses. These findings are likely to result in new platforms for engineering stress tolerant crops in the future.