Key aspects of RNAi movement deciphered

RNA interference (RNAi) has been long known to move between cells and over long distance in plants, yet the signalling  molecule(s) have remained controversial. In a recent publication in Nature Plants, the Voinnet group has now solved this issue unambiguously and simultaneously discovered a process that lends mobile RNAi almost boundless flexibility and versatility in shaping gene expression across distances, well beyond those afforded by linear diffusion gradients.