[The roles of RNA silencing in plant biotic stress].

RNA silencing is a common strategy shared by eukaryotic organisms to regulate gene expression, and also can operate as a defense mechanism against biotic stress. In plants, small RNAs play an important role in defensing against viruses, bacteria or herbivore attack, such as miRNAs and siRNAs. As a response to this defense system, both viruses and bacteria have evolved viral suppressors of RNA silencing (VSRs) or bacterial suppressors of RNA silencing (BSRs) to overcome the host silencing response, which can act at various steps of the different silencing pathways. This review highlights the current understanding and the new insights concerning of the roles of small RNAs in defensing against biotic stress and the mechanism of VSRs and BSRs in suppressing host RNA silencing in plants.