May regulate an early stage of the zoospore pathway. ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] Interacts with BZP1. Expressed in zoospores. Not detected in non-sporulating hyphae, hyphae decorated with sporangia, ungerminated sporangia and directly germinating sporangia. Up-regulated by exposure of sporangia to cool water, which initiates the cleavage of sporangial cytoplasm into individual zoospores. Belongs to the protein kinase superfamily. CAMK Ser/Thr protein kinase family.