ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] By salicylic acid (SA) or by a bacterial pathogen infection. May be regulated by WRKY DNA-binding proteins at the transcriptional level. May be due to a competing acceptor splice site. Belongs to the protein kinase superfamily. Ser/Thr protein kinase family. CRK subfamily.