Chapter 3: "Exogenous Application of RNAs as a Silencing Tool for Discovering Gene Function" - In the book "RNAi for plant improvement and protection"

RNA silencing is a powerful technique to unravel the function of genes by inhibiting gene expression at the post-transcriptional level. This technique is particularly appropriate for studying developmental processes such as fruit setting and growth that require a tight organ/tissue and time-specific regulation of target genes expression. Gene silencing in plants is usually achieved by the stable or transient expression of genetic constructs producing hairpin (hp) RNA or microRNA (miRNA). The use of exogenously applied small RNAs (sRNAs) and long doublestranded RNAs (dsRNAs) for transient gene silencing in whole plant and/or detached organs would allow a much higher number of genes to be analysed in a shorter time. The successful application of this technique requires efficient systems for sRNA delivery as well as methods to enhance RNA stability in plant cells.