MAP kinases in plant signal transduction

Mitogen-activated protein kinase (MAPK) pathways are modules involved in th e transduction of extracellular signals to intracellular targets in all euk aryotes. Distinct MAPK pathways are regulated by different extracellular st imuli and are implicated in a wide variety of biological processes. In plan ts there is evidence for MAPKs playing a role in the signaling of abiotic s tresses, pathogens and plant hormones. The large number and divergence of p lant MAPKs indicates that this ancient mechanism of bioinformatics is exten sively used in plants and may provide a new molecular handle on old questio ns.