PpSCARECROW1 (PpSCR1) regulates leaf blade and mid-vein development in Physcomitrium patens

Asymmetric cell divisions in plants generate diverse cell types, and the SCARECROW (SCR) transcription factor controls such divisions in flowering plants. However, limited knowledge exists about SCR's role in leaf development in non-flowering plants. Our analysis revealed three SCR homologs in the moss Physcomitrium patens, with PpSCR1 showing high expression in gametophores and having a prominent role in leaf development. Knock-out of PpSCR1 resulted in slender leaves with narrow blades and thick mid-veins, indicating its involvement in cell division regulation.