ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] Interacts with ARAC5 and ARAC10. Mostly expressed in vasculature, hydathode endothem, leaf mesophyll cells and trichomes. By fungal pathogens such as Phytophthora infestans and Botrytis cinerea. Promoted by ethylene in the vascular cylinder of primary roots and in the root cortex in the root/hypocotyl junction zone. Belongs to the protein kinase superfamily. Ser/Thr protein kinase family.