In the most recent years, each of the RNA silencing pathways of plants have appeared to generate ncRNAs with dedicated functions, specialized biological activities and specific functional scopes. RNA silencing plays a crucial role in coordinating the expression, stability, protection and inheritance of eukaryotic genomes. It compromises several mechanisms, that invariably depend on core small non coding RNAs and that achieve dedicated sequence-specific functions. RNA silencing has been recognized to carry critical developmental, stress-response and bodyguard functions be coordinating the expression, protection, stability and inheritance of virtually all eukaryotic genomes. Thus, the ncRNAs encompass a wide set of mechanisms that achieve specialized functions.