Small RNAs are short RNA molecules that help determine which genes in a cell are switched on or off. Until now, it was assumed that the small RNAs necessary for pollen development originate in the pollen itself and in the directly surrounding maternal tissue. However, a new study conducted by the MPI-MP reveals a surprisingly different picture: The crucial signals do not originate in the pollen, but in maternal tissue and can be transported over long distances, for example from the roots.