title: Ethylene signaling is required for the acceleration of cell death induced by the activation of AtMEK5 in Arabidopsis.
abstract: Mitogen-activated protein kinases (MAPKs) are involved in the regulation of plant growth, development and responses to a wide variety of stimuli. In a conditional gain-of-function transgenic system, the activation of AtMEK5, a MAPK kinase, can in turn activate endogenous AtMAPK3 and AtMAPK6, and can lead to a striking increase in ethylene production and induce hypersensitive response (HR)-like cell death in Arabidopsis. However, the role of the increased ethylene production in regulating this HR-like cell death remains unknown. Using Arabidopsis transgenic plants that express AtMEK5(DD), an active mutant of AtMEK5 that is under the control of a steroid-inducible promoter, we tested the contribution of ethylene to cell death. We found that ethylene biosynthesis occurs before cell death. Cell death was delayed by inhibiting AtMEK5-induced ethylene production using inhibitors of ACC-synthases, ACC-oxidases or ethylene receptors. In the mutants AtMEK5(DD)/etr1-1 and AtMEK5(DD)/ein2-1, both of which showed insensitivity to ethylene, the expression of AtMEK5(DD) protein, activity of AtMAPK3 and AtMAPK6, and ethylene production were the same as those seen in AtMEK5(DD) transgenic plants, but cell death was also delayed. These data suggest that ethylene signaling perception is required to accelerate cell death that is induced by AtMEK5 activation.
authors.affiliation: State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100094, China.
authors.forename: Hongxia
authors.initials: H
authors.lastname: Liu
authors.forename: Ying
authors.initials: Y
authors.lastname: Wang
authors.forename: Juan
authors.initials: J
authors.lastname: Xu
authors.forename: Tongbing
authors.initials: T
authors.lastname: Su
authors.forename: Guoqin
authors.initials: G
authors.lastname: Liu
authors.forename: Dongtao
authors.initials: D
authors.lastname: Ren
mesh_terms: D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D016923:Cell Death / Q000235:genetics; D004789:Enzyme Activation / Q000235:genetics; D005030:Ethylenes / Q000096:biosynthesis*; D008190:Lyases / Q000235:genetics / Q000378:metabolism; D048671:MAP Kinase Kinase 5 / Q000235:genetics / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3 / Q000235:genetics / Q000378:metabolism; D048053:Mitogen-Activated Protein Kinase 6 / Q000235:genetics / Q000378:metabolism; D009154:Mutation; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified / Q000201:enzymology / Q000235:genetics; D011401:Promoter Regions, Genetic / Q000502:physiology; D011956:Receptors, Cell Surface / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology*
chemical_list: D029681:Arabidopsis Proteins; D005030:Ethylenes; D010940:Plant Proteins; D011956:Receptors, Cell Surface; C083750:ethylene receptors, plant; C036216:ethylene; D048052:Mitogen-Activated Protein Kinase 3; D048053:Mitogen-Activated Protein Kinase 6; D048671:MAP Kinase Kinase 5; D008190:Lyases; C021773:1-aminocyclopropanecarboxylate synthase