Figure 6.

miR156-Targeted SPL Regulates Regenerative Capacity.

(A) Shoot regeneration assay using the wild type (Columbia-0 [Col-0]) and Pro35S:rSPL9-GR. The hypocotyls were cultured on CIM and then transferred to MS medium supplemented with different concentrations of 2-isopentenyladenine (2-IP) and DEX. Bar = 0.5 cm.

(B) Quantitative analyses of regenerative capacity. The regenerative rate was represented by the number of regenerated shoots on six explants. Data are means ± sd of three biological replicates.

(C) Model for the regulation of shoot regenerative capacity by a microRNA timer. In old plants, the amount of SPL9 is increased due to the developmental decline of miR156. SPL9 inhibits the transcriptional activity of B-type ARRs, thereby reducing the shoot regenerative capacity (see text for details).