The Arabidopsis receptor kinase IRK is polarized and represses specific cell division (Devel. Cell) ($)

Orientation of cell division decides daughter cell fate and is fundamentally important for tissue patterning and morphology. For instance, asymmetric cell division leads to the generation of new cell types; in contrast, symmetric division produces cells with similar identity in a proliferative manner. Campos et al. studied proteins involved in tissue patterning in Arabidopsis thaliana root. They identified INFLORESCENCE AND ROOT APICES RECEPTOR KINASE (IRK), a LRR-RLKs that is polarized in the ground tissue and important for its patterning. IRK localizes into distinct plasma membrane domains in various cell types depending on the radially adjacent cells, and irk mutants show radially abnormal cell division in the endodermis. In the signaling cascade, IRK downregulates CYCD6;1 and regulates endodermal cell division. As a result, in the irk mutant, the repression of CYCD6;1 through IRK is inactive and causing abnormal endodermal cell division in the radial axis. Altogether, this study provided the mechanistic explanation on ground tissue patterning through polarly localized IRK protein. (Summary by Arif Ashraf) Developmental Cell 10.1016/j.devcel.2019.12.001