title: Induction of hypersensitive cell death by hydrogen peroxide produced through polyamine degradation in tobacco plants.
abstract: Screening immediate-early responding genes during the hypersensitive response (HR) against tobacco mosaic virus infection in tobacco (Nicotiana tabacum) plants, we identified a gene encoding ornithine decarboxylase. Subsequent analyses showed that other genes involved in polyamine biosynthesis were also up-regulated, resulting in the accumulation of polyamines in apoplasts of tobacco mosaic virus-infected leaves. Inhibitors of polyamine biosynthesis, alpha-difluoromethyl-ornithine, however, suppressed accumulation of polyamines, and the rate of HR was reduced. In contrast, polyamine infiltration into a healthy leaf induced the generation of hydrogen peroxide and simultaneously caused HR-like cell death. Polyamine oxidase activity in the apoplast increased up to 3-fold that of the basal level during the HR, and its suppression with a specific inhibitor, guazatine, resulted in reduced HR. Because it is established that hydrogen peroxide is one of the degradation products of polyamines, these results indicate that one of the biochemical events in the HR is production of polyamines, whose degradation induces hydrogen peroxide, eventually resulting in hypersensitive cell death.
authors.affiliation: Research and Education Center for Genetic Information, Nara Institute of Science and Technology, Nara 630-0192, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Yoda
authors.forename: Yube
authors.initials: Y
authors.lastname: Yamaguchi
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Sano
mesh_terms: D016923:Cell Death; D018506:Gene Expression Regulation, Plant; D006861:Hydrogen Peroxide / Q000378:metabolism*; D000587:Oxidoreductases Acting on CH-NH Group Donors / Q000235:genetics / Q000378:metabolism; D018515:Plant Leaves / Q000166:cytology / Q000201:enzymology / Q000378:metabolism / Q000821:virology; D011073:Polyamines / Q000378:metabolism*; D014026:Nicotiana / Q000166:cytology / Q000201:enzymology / Q000378:metabolism* / Q000821:virology*; D014027:Tobacco Mosaic Virus / Q000502:physiology*; D000097667:Polyamine Oxidase
chemical_list: D006861:Hydrogen Peroxide; D000587:Oxidoreductases Acting on CH-NH Group Donors; D011073:Polyamines; D000097667:Polyamine Oxidase