Regulates the transition between growth and differentiation. Expressed in vegetative cells only (at protein level). The protein kinase domain is predicted to be catalytically inactive. Cells overexpress discoidin and initiate multicellular development prematurely. In the N-terminal section; belongs to the GDT family. In the C-terminal section; belongs to the protein kinase superfamily. TKL Ser/Thr protein kinase family.