title: Influence of the photoperiod on redox regulation and stress responses in Arabidopsis thaliana L. (Heynh.) plants under long- and short-day conditions.
abstract: Arabidopsis thaliana L. (Heynh.) plants were grown in low light (150 micromol photons m(-2) s(-1) and 20 degrees C) either in short days (7.5 h photoperiod) or long days (16 h photoperiod), and then transferred into high light and low temperature (350-800 micromol photons m(-2) s(-1) at 12 degrees C). Plants grown in short days responded with a rapid increase in NADP-malate dehydrogenase (EC 1.1.1.82) activation state. However, persisting overreduction revealed a new level of regulation of the malate valve. Activity measurements and Northern-blot analyses indicated that NADP-malate dehydrogenase transcript and protein levels increased within a few hours. Using macroarrays, additional changes in gene expression were identified. Transcript levels for several enzymes of glutathione metabolism and of some photosynthetic genes increased. The cellular glutathione level increased, but its redox state remained unchanged. A different situation was observed in plants grown in long-day conditions. Neither NADP-malate dehydrogenase nor glutathione content changed, but the expression of several antioxidative enzymes increased strongly. We conclude that the endogenous systems that measure day length interact with redox regulation, and override the interpretation of the signals, i.e. they redirect redox-mediated acclimation signals to allow for more efficient light usage and redox poising in short days to systems for the prevention of oxidative damages when grown under long-day conditions.
authors.affiliation: Pflanzenphysiologie, Fachbereich Biologie/Chemie, Universität Osnabrück, 49069, Osnabrück, Germany.
authors.forename: Beril
authors.initials: B
authors.lastname: Becker
authors.forename: Simone
authors.initials: S
authors.lastname: Holtgrefe
authors.forename: Sabrina
authors.initials: S
authors.lastname: Jung
authors.forename: Christina
authors.initials: C
authors.lastname: Wunrau
authors.forename: Andrea
authors.initials: A
authors.lastname: Kandlbinder
authors.forename: Margarete
authors.initials: M
authors.lastname: Baier
authors.forename: Karl-Josef
authors.initials: KJ
authors.lastname: Dietz
authors.forename: Jan E
authors.initials: JE
authors.lastname: Backhausen
authors.forename: Renate
authors.initials: R
authors.lastname: Scheibe
mesh_terms: D000975:Antioxidants / Q000378:metabolism; D017360:Arabidopsis / Q000502:physiology* / Q000528:radiation effects*; D002734:Chlorophyll / Q000378:metabolism; D005453:Fluorescence; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant / Q000235:genetics; D008027:Light; D050538:Malate Dehydrogenase (NADP+) / Q000378:metabolism; D008293:Malates / Q000378:metabolism; D010084:Oxidation-Reduction / Q000528:radiation effects; D017440:Photoperiod; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D000975:Antioxidants; D008293:Malates; D012333:RNA, Messenger; D002734:Chlorophyll; D050538:Malate Dehydrogenase (NADP+)