Figure 1.

Graft-transmissible gene silencing in Arabidopsis. A, A graft between a 35S-GFP scion and 35S-hpGF rootstock 3 d after grafting. B, Graft as in A showing initial silencing 10 d after grafting. C, Bizonal silencing (arrow) in scion leaves 22 d after grafting. D, Vascular silencing pattern in GFP-expressing N. benthamiana plants infiltrated with a hpGF construct in the lower leaves. E, Some Arabidopsis grafts show initial vascular silencing followed by bizonal leaf silencing (arrow). F, GFP expression is recovered in the seeds of fully silenced scions (left). On the right is a wild-type Col-0 silique (WT). G, In 20 grafts of 35S-GFP on hpGF rootstock, the majority showed initial silencing on the seventh or eighth leaf. H, In both short-day (SD) and long-day (LD) conditions, initial silencing was seen in the seventh leaf.