miR172 Can Move Long Distances in Nicotiana benthamiana

Small interfering RNAs can induce RNA silencing throughout plants owing to their ability to move through the phloem. Although microRNA (miRNA), another noncoding small RNA that regulates protein-coding RNAs through transcript cleavage or translational inhibition, has also been detected in phloem, there are few reports of its long-distance movement via phloem. We investigated whether miR172 molecules can move systemically from source tissues to sink tissues in Nicotiana benthamiana. Results of agro-infiltration and micro-grafting experiments indicate that miR172 can move long distances.