Mitogen-activated protein kinase involved in a signal transduction pathway that is activated by changes in the osmolarity of the extracellular environment. Controls osmotic regulation of transcription of target genes (By similarity). Involved in the virulence and conidia formation. Mediates tannic acid-induced laccase expression and cryparin expression. ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] Activated by tyrosine and threonine phosphorylation (By similarity). Hypoviruses like CHV1-EP713 induce inactivation by lowering the degree of phosphorylation in response to various environmental stresses. The TXY motif contains the threonine and tyrosine residues whose phosphorylation activates the MAP kinases. Dually phosphorylated on Thr-171 and Tyr-173, which activates the enzyme (By similarity). Phosphorylated in response of osmotic stress. Belongs to the protein kinase superfamily. Ser/Thr protein kinase family. MAP kinase subfamily. HOG1 sub-subfamily.