title: Production of reactive species and modulation of antioxidant network in response to heat shock: a critical balance for cell fate.
abstract: Exposure to adverse temperature conditions is a common stress factor for plants. In order to cope with heat stress, plants activate several defence mechanisms responsible for the control of reactive oxygen species (ROS) and redox homeostasis. Specific heat shocks (HSs) are also able to activate programmed cell death (PCD). In this paper, the alteration of several oxidative markers and ROS scavenging enzymes were studied after subjecting cells to two different HSs. Our results suggest that, under moderate HS, the redox homeostasis is mainly guaranteed by an increase in glutathione (GSH) content and in the ascorbate peroxidase (APX) and catalase (CAT) activities. These two enzymes undergo different regulatory mechanisms. On the other hand, the HS-induced PCD determines an increase in the activity of the enzymes recycling the ascorbate- and GSH-oxidized forms and a reduction of APX; whereas, CAT decreases only after a transient rise of its activity, which occurs in spite of the decrease of its gene expression. These results suggest that the enzyme-dependent ROS scavenging is enhanced under moderate HS and suppressed under HS-induced PCD. Moreover, the APX suppression occurring very early during PCD, could represent a hallmark of cells that have activated a suicide programme.
authors.affiliation: Dipartimento di Biologia e Patologia Vegetale, Università degli Studi di Bari, Bari, Italy.
authors.forename: Vittoria
authors.initials: V
authors.lastname: Locato
authors.forename: Cosimo
authors.initials: C
authors.lastname: Gadaleta
authors.forename: Laura
authors.initials: L
authors.lastname: De Gara
authors.forename: Maria Concetta
authors.initials: MC
authors.lastname: De Pinto
mesh_terms: D000975:Antioxidants / Q000378:metabolism*; D060387:Ascorbate Peroxidases; D002374:Catalase / Q000378:metabolism; D002470:Cell Survival; D002478:Cells, Cultured; D005978:Glutathione / Q000378:metabolism; D018869:Heat-Shock Response; D006861:Hydrogen Peroxide / Q000378:metabolism*; D015227:Lipid Peroxidation; D008856:Microscopy, Fluorescence; D009569:Nitric Oxide / Q000378:metabolism; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D010544:Peroxidases / Q000378:metabolism; D018749:RNA, Plant / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014026:Nicotiana / Q000235:genetics / Q000378:metabolism
chemical_list: D000975:Antioxidants; D018749:RNA, Plant; D009569:Nitric Oxide; D006861:Hydrogen Peroxide; D010544:Peroxidases; D060387:Ascorbate Peroxidases; D002374:Catalase; D005978:Glutathione