Figure 5.

Auxin transport is reduced in RPN9⁻ plants. A, PINOID mRNA is reduced at 8 DPS in RPN9⁻ plants. Three biological samples were tested and gave similar results. Error bars represent the sd of the mean. B, Distribution of [¹⁴C]IAA in the midveins at 10 DPS after 18-h incubation with labeled IAA. a to c, Control (basipetal). d, Control (acropetal). e to g, RPN9⁻ (basipetal). h, RPN9⁻ (acropetal). i to k, Control + 60 μm NPA (basipetal). The box indicates the upper 1-cm parts used for quantification. C, Amounts of [¹⁴C]IAA transported to the upper 1 cm of vein sections after 18-h incubation. Error bars are the sd from three replicates for each treatment. The experiment was repeated once with a different set of silenced plants and gave similar results. D, NPA treatment induces vascular formation in wild-type N. benthamiana plants. Plants were grown on Murashige and Skoog medium without or with 25 μm of NPA for 3 weeks; leaves were cleared as described (Sieburth, 1999). E, NPA treatment induces vascular formation and partially inhibits viral transport. Cross sections of leaf margins are shown on the left, vascular bundles are circled. TMV-GFP was inoculated 1 week after NPA treatment and pictures were taken at 7 DPI of TMV-GFP infection.