title: Ozone-sensitive arabidopsis rcd1 mutant reveals opposite roles for ethylene and jasmonate signaling pathways in regulating superoxide-dependent cell death.
abstract: We have isolated a codominant Arabidopsis mutant, radical-induced cell death1 (rcd1), in which ozone (O(3)) and extracellular superoxide (O(2)(*)-), but not hydrogen peroxide, induce cellular O(2)(*)- accumulation and transient spreading lesions. The cellular O(2)(*)- accumulation is ethylene dependent, occurs ahead of the expanding lesions before visible symptoms appear, and is required for lesion propagation. Exogenous ethylene increased O(2)(*)--dependent cell death, whereas impairment of ethylene perception by norbornadiene in rcd1 or ethylene insensitivity in the ethylene-insensitive mutant ein2 and in the rcd1 ein2 double mutant blocked O(2)(*)- accumulation and lesion propagation. Exogenous methyl jasmonate inhibited propagation of cell death in rcd1. Accordingly, the O(3)-exposed jasmonate-insensitive mutant jar1 displayed spreading cell death and a prolonged O(2)(*)- accumulation pattern. These results suggest that ethylene acts as a promoting factor during the propagation phase of developing oxyradical-dependent lesions, whereas jasmonates have a role in lesion containment. Interaction and balance between these pathways may serve to fine-tune propagation and containment processes, resulting in alternate lesion size and formation kinetics.
authors.affiliation: Institute of Biotechnology and Department of Biosciences, University of Helsinki, POB 56 (Viikinkaari 5 D), FIN-00014 Helsinki, Finland.
authors.forename: K
authors.initials: K
authors.lastname: Overmyer
authors.forename: H
authors.initials: H
authors.lastname: Tuominen
authors.forename: R
authors.initials: R
authors.lastname: Kettunen
authors.forename: C
authors.initials: C
authors.lastname: Betz
authors.forename: C
authors.initials: C
authors.lastname: Langebartels
authors.forename: H
authors.initials: H
authors.lastname: Sandermann
authors.forename: J
authors.initials: J
authors.lastname: Kangasjärvi
mesh_terms: D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D016923:Cell Death; D003517:Cyclopentanes / Q000494:pharmacology*; D005020:Ethyl Methanesulfonate; D005030:Ethylenes / Q000494:pharmacology*; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D007700:Kinetics; D008969:Molecular Sequence Data; D016296:Mutagenesis; D054883:Oxylipins; D010126:Ozone / Q000494:pharmacology*; D010937:Plant Growth Regulators / Q000494:pharmacology*; D018515:Plant Leaves / Q000502:physiology; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D013481:Superoxides / Q000378:metabolism / Q000494:pharmacology; D014158:Transcription, Genetic
chemical_list: D003517:Cyclopentanes; D005030:Ethylenes; D054883:Oxylipins; D010937:Plant Growth Regulators; D013481:Superoxides; D010126:Ozone; C011006:jasmonic acid; C036216:ethylene; D005020:Ethyl Methanesulfonate