Transcriptional activity of gene expression in the endodermis and cortex at approximately 75% relative position of the root as well as in the inner cortex close to the root-shoot junction. Expression analysis of KUP8 and HKT1 in Col-0 and myb68-2 was performed using fluorescent transcriptional marker lines (expressing pKUP8:NLS3xVenus or pHKT1:NLS-3xmScarlet, respectively). Each data point represents the percentage of cells with expression in individual roots (a minimum 7 cells per root). For HAK5 mRNA, fluorescence in situ hybridization was employed. As negative control, either a probe specific for a bacterial gene (dapB, Bacillus subtilis) with the corresponding amplifier or only the amplifier used for HAK5 without a probe was used (see STAR Methods). For boxplots, the center line indicates the median, dots represent data points, the box limits represent the upper and lower quartiles, and the whiskers represent the maximum and minimum values. Individual letters show significance according to a Kruskal-Wallis test with a post hoc Nemenyi test. XPE, xylem pole-associated endodermal cells; PPE, phloem pole-associated endodermal cells; NPE, non-pole-associated endodermal cells; Ep, epidermis; Co, cortex; En, endodermis; nd, not detected; ns, not significant. Scale bars represent 25 m.
