Figure 4. Loss of SDG2 partially affects auxin regulation in roots. A.

and B, Comparison of the expression pattern of DR5:GFP reporter in 5-day-old wild-type Col and the mutant sdg2-3, respectively. Note that auxin gradient maximum in QC visualized by DR5:GFP expression in Col is lost in sdg2-3. Bar = 50 µm. C, Relative gene expression levels determined by quantitative RT-PCR analysis. RNA was prepared from roots of 20-day-old Col or sdg2-3 seedlings. RT-PCR was performed using gene specific primers and normalized using ACTIN2 as reference. Relative expression levels of the indicated genes are shown as mean values from three biological repeats and with Col value setting as 1. Bars indicate SD. D, Effects of exogenous NAA on root elongation of Col and sdg2-3 seedlings. Seeds were germinated and grown on medium containing the indicated concentration of NAA. Root length is shown as a mean value obtained from three independent experiments with each experiment comprising 20 plants. Bar indicates SD. E, Effects of exogenous NAA on lateral root (LR) formation of Col and sdg2-3 seedlings. LR and primordia were counted using the GUS reporter of 10-day-old Col or sdg2-3 seedlings expressing CYCB1;1:GUS. The total number of LR and primordia was divided by root length to report LR formation ability of individual plants. Mean values obtained from three independent experiments and 20 plants per sample per experiment are shown, and bars indicate SD.