In young roots (up to 7 days old), MYB68 shows activity in both meristematic and suberizing regions. In the meristem, our work proposes that it represses periclinal cell divisions in the endodermis, which represses the formation of middle cortex (MC) cells as well as differential steps leading to the formation of endodermal passage cells (PCs). In the suberized zone, MYB68 is likely involved in indirect regulation of the suberization machinery. As the root ages past 7 days (old root), our data support that MYB68 expression is delayed outside the meristematic region. As a consequence, the absence of the repressing effect of MYB68 on periclinal division in the meristematic region enables MC formation in the xylem pole. This correlates with an observed delay in suberization, which suggests a connection between MC cell and PC formation via MYB68. Moreover, at this stage, the root undergoes secondary growth (sec. growth) and forms the protective periderm via radial divisions. Here, MYB68 serves to control suberization and cell division rate.19
