Figure 2.PDCB1 is expressed in lateral roots and upregulated after exposure to auxins. Expression was reported by GUS activity using the reporter lines pPDCB1::GUS (A-H). Staining of 10-d-old seedling revealed gene expression in stages II–III (A), IV–V (B), and VI (C) lateral root primordia. 24h treatment with 10 µM NAA greatly upregulates PDCB1 expression in emerging lateral roots and dividing pericycle cells (D). Staining of seedlings grown in 10 µM NPA and transferred to 1 µM NAA for 4h (E), 12h (F), and 24h (G-H) showed time-dependent PDCB1 response to exogenous auxins. Arrow in (G-H) indicates maxima of gene expression in the upper boundary of the primordia. Scale bars: 20 µm.