Stress activated MAPKs in plants

摘要: Plants are exposed to a wide variety of extracellular stimuli and employ broad set signaling pathways give the appropriate response. M itogen ctivated p rotein k inases (MAPKs) play an important role in signal transduction yeast animals increasing evidence suggests similar MAPKs plants. their function as part protein kinase cascades, composed MAPK, AP K inase (MKK), (MKKK). MKKKs activate MKKs by phosphorylation conserved threonine or serine residues, subsequently highly tyrosine residues. The introduction gives brief overview MAPK cascades employed more extensive our current knowledge about To get plant functions known were classified analyses all isolated full-length sequences reveals that they can be divided into at least five distinct subfamilies (Chapter 2). For some these groups it could shown with also perform functions. In addition, analysis e xpressed s equence t ags (ESTs) partial cDNAs coding for revealed existence new subfamily. goal research described this thesis was provide insight several stress responses One most severe environmental stresses which plants is wounding. It result physical injury, herbivore pathogen attack induces range responses, general involving induction genes active healing defense processes. chapter 3 involvement wound response alfalfa discussed. wounding activates tress (SAMK) both post-translational transcriptional level. inactivation but not activation SAMK dependent on de novo transcription translation. Another attack. various pathogens normally activated specific derived factors (elicitors). A 13 amino acid oligopeptide fragment from 42 kDa glycoprotein pathogenic fungus Phytophthora sojae used. Treatment parsley cells elicitor results responses. leading include ion channels production reactive oxygen species. identified upon treatment 4). This act downstream channel upstream independently oxidative burst. translocated nucleus after elicitor, where might responsible expression genes. extend other species, analyzed. Two kinases relative molecular masses 44-kD 46-kD found rapidly transiently 5). These SIMK ( tress- i nducible inase), respectively. Yeast elicitor-induced medium alkalinisation, burst, blocked inhibitor K252a, demonstrating mediating However, involved alkalinisation because staurosporine, another inhibitor, did affect totally inhibited data show whereas burst depend pathways, lie separate elicitor-activated cascades. summary provided proof plants, further will needed elucidate exact respective pathways.