A guide to plant siRNAs
In a recent review published in Plant Cell, Olivier Voinnet (IMPB) and his colleague Hervé Vaucheret (INRAE, Versailles) provide an in-depth and comprehensive overview of the plant siRNA landscape, emphasizing the extraordinary diversity of their biogenesis and functions.
Small interfering (si)RNAs and micro (mi)RNAs are the two classes of silencing small RNAs found in plants. Although they differ in the biogenesis, both types of molecules exert their functions via ARGONAUTE effector proteins. Whereas miRNAs are considered the clean, noble side of the plant small RNA world, siRNAs are often seen as a noisy set of molecules whose barbarian acronyms reflect a large diversity of often elusive origins and functions. Furthermore, twenty-five years after their discovery in plants and the recognition of their critical role in antiviral RNA silencing, new classes of endogenous, as opposed to virus-derived siRNAs are still being identified, sometimes in discrete tissues or at particular developmental stages.
Focusing primarily on the model Arabidopsis, the authors review the current state-of-the-art of the plant siRNA landscape, including transposable elements (TE)-derived siRNAs, a vast array of non–TE-derived endogenous siRNAs, as well as exogenous siRNAs produced in response to invading nucleic acids such as viruses or transgenes. It primarily emphasizes the extraordinary sophistication and diversity of their biogenesis and, secondarily, the variety of their known or presumed functions, including via non-cell autonomous activities, in the sporophyte, gametophyte, and shortly after fertilization.
Link to the paper in external pageexternal page"Plant Cell"