MULTIPLE ROLES OF MAP KINASES IN PLANT SIGNAL-TRANSDUCTION

The MAP kinases are important mediators of intracellular signal transd uction, and regulation involving them has been implicated in a wide va riety of physiological processes. Studies in yeast and mammals have id entified subgroups of these enzymes that have different substrate spec ificities and are regulated by different extracellular stimuli. Recent ly, studies in plants have revealed that there is a similar divergence of MAP kinase functions, and pathways involving MAP kinases have been linked to signal transduction caused by wounding, pathogens and abiot ic stresses, as well as the plant hormones abscisic acid, auxin and et hylene. Thus, pathways involving MAP kinases are a common mechanism fo r signal transduction in all eukaryotes, and have been adapted to coup le distinct stimuli to specific physiological responses.