Techniques for RNA in vivo imaging in plants

Since the discovery of small RNAs and RNA silencing, RNA biology has taken a centre stage in cell and developmental biology. Small RNAs, but also mRNAs and other types of cellular and viral RNAs are processed at specific subcellular localizations. To fully understand cellular RNA metabolism and the various processes influenced by it, techniques are required that permit the sequence-specific tracking of RNAs in living cells. A variety of methods for RNA visualization have been developed since the 1990s, but plant cells pose particular challenges and not all approaches are applicable to them. On the other hand, plant RNA metabolism is particularly diverse and RNAs are even transported between cells, so RNA imaging can potentially provide many valuable insights into plant function at the cellular and tissue level. This Short Review briefly introduces the currently available techniques for plant RNA in vivo imaging and discusses their suitability for different biological questions.