title: Nitric oxide is involved in cadmium-induced programmed cell death in Arabidopsis suspension cultures.
abstract: Exposure to cadmium (Cd(2+)) can result in cell death, but the molecular mechanisms of Cd(2+) cytotoxicity in plants are not fully understood. Here, we show that Arabidopsis (Arabidopsis thaliana) cell suspension cultures underwent a process of programmed cell death when exposed to 100 and 150 microm CdCl(2) and that this process resembled an accelerated senescence, as suggested by the expression of the marker senescence-associated gene12 (SAG12). CdCl(2) treatment was accompanied by a rapid increase in nitric oxide (NO) and phytochelatin synthesis, which continued to be high as long as cells remained viable. Hydrogen peroxide production was a later event and preceded the rise of cell death by about 24 h. Inhibition of NO synthesis by N(G)-monomethyl-arginine monoacetate resulted in partial prevention of hydrogen peroxide increase, SAG12 expression, and mortality, indicating that NO is actually required for Cd(2+)-induced cell death. NO also modulated the extent of phytochelatin content, and possibly their function, by S-nitrosylation. These results shed light on the signaling events controlling Cd(2+) cytotoxicity in plants.
authors.affiliation: Dipartimento di Biologia, Università degli Studi di Padova, I-35131 Padova, Italy. demicheler@virgilio.it
authors.forename: Roberto
authors.initials: R
authors.lastname: De Michele
authors.forename: Emanuela
authors.initials: E
authors.lastname: Vurro
authors.forename: Chiara
authors.initials: C
authors.lastname: Rigo
authors.forename: Alex
authors.initials: A
authors.lastname: Costa
authors.forename: Lisa
authors.initials: L
authors.lastname: Elviri
authors.forename: Marilena
authors.initials: M
authors.lastname: Di Valentin
authors.forename: Maria
authors.initials: M
authors.lastname: Careri
authors.forename: Michela
authors.initials: M
authors.lastname: Zottini
authors.forename: Luigi
authors.initials: L
authors.lastname: Sanità di Toppi
authors.forename: Fiorella
authors.initials: F
authors.lastname: Lo Schiavo
mesh_terms: D017209:Apoptosis / Q000187:drug effects* / Q000502:physiology; D017360:Arabidopsis / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000378:metabolism; D060387:Ascorbate Peroxidases; D002104:Cadmium / Q000633:toxicity*; D002374:Catalase / Q000378:metabolism; D018929:Cell Culture Techniques; D016922:Cellular Senescence / Q000187:drug effects; D003546:Cysteine Endopeptidases / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism / Q000502:physiology*; D010544:Peroxidases / Q000378:metabolism; D054811:Phytochelatins / Q000494:pharmacology; D015398:Signal Transduction
chemical_list: D029681:Arabidopsis Proteins; D002104:Cadmium; D009569:Nitric Oxide; D054811:Phytochelatins; D006861:Hydrogen Peroxide; D010544:Peroxidases; D060387:Ascorbate Peroxidases; D002374:Catalase; C402082:SAG12 protein, Arabidopsis; D003546:Cysteine Endopeptidases