Small RNAs in development - insights from plants

► Small RNAs move cell-to-cell and systemically in plants. ► Some plant miRNAs have the capacity to trigger the production of secondary siRNAs to impact plant development.► AGO10 acts in plant development through sequence-specific small RNA sequestration. ► Heterochromatic siRNAs in plants and piRNAs in mammals silence transposable elements by guiding DNA methylation. ► Heterochromatic siRNAs in plants and piRNAs in animals impact germ line specification and meiosis.