Figure 4.

Inducible GFP silencing in the roots of Dex-induced RtSS plants, and time course of production of 21-nucleotide siRNAs from the hpGF. A, A plant without Dex. B, Two days after Dex treatment. C, Initial silencing in the root can be seen 3 d after treatment. D to G, Silencing becomes more obvious with time. H, Roots are completely silenced by 12 d after Dex treatment. White arrows indicate the silenced roots. I, Small RNA northern-blot analysis of roots treated with Dex. WT, Wild-type Col-0 Arabidopsis. Roots of T1, T2, and T3 plants on MS medium without Dex (indicated by 0) were used as controls. Roots from the T3 generation treated with Dex showed increasing expression of 21-nucleotide (nt) siRNAs from the GF and P, with a peak 3 d after, and maintained at 12 d after induction.