Figure 9.

Model describing artificial small RNA (art‐sRNA) biogenesis, silencing activity and movement from source to distal plant tissues. The art‐sRNA duplexes are produced in source cells by DCL1‐ or DCL4‐mediated processing of artificial microRNA (amiRNA) or synthetic trans‐acting small interfering RNA (syn‐tasiRNA) precursors, respectively. The guide strand (in blue) of the art‐sRNA duplex is incorporated into ARGONAUTE1 (AGO1) to bind and cleave NbSu target mRNAs. The art‐sRNA duplexes most likely move cell to cell through plasmodesmata and long‐distance through the phloem stream using the sieves elements. The art‐sRNA duplexes may exit the sieve elements and move 10–15 cells away. [Colour figure can be viewed at wileyonlinelibrary.com]