title: The essential role of sugar metabolism in the acclimation response of Arabidopsis thaliana to high light intensities.
abstract: Retrograde signals from chloroplasts are thought to control the expression of nuclear genes associated with plastidial processes such as acclimation to varying light conditions. Arabidopsis mutants altered in the day and night path of photoassimilate export from the chloroplasts served as tools to study the involvement of carbohydrates in high light (HL) acclimation. A double mutant impaired in the triose phosphate/phosphate translocator (TPT) and ADP-glucose pyrophosphorylase (AGPase) (adg1-1/tpt-2) exhibits a HL-dependent depletion in endogenous carbohydrates combined with a severe growth and photosynthesis phenotype. The acclimation response of mutant and wild-type plants has been assessed in time series after transfer from low light (LL) to HL by analysing photosynthetic performance, carbohydrates, MgProtoIX (a chlorophyll precursor), and the ascorbate/glutathione redox system, combined with microarray-based transcriptomic and GC-MS-based metabolomic approaches. The data indicate that the accumulation of soluble carbohydrates (predominantly glucose) acts as a short-term response to HL exposure in both mutant and wild-type plants. Only if carbohydrates are depleted in the long term (e.g. after 2 d) is the acclimation response impaired, as observed in the adg1-1/tpt-2 double mutant. Furthermore, meta-analyses conducted with in-house and publicly available microarray data suggest that, in the long term, reactive oxygen species such as H₂O₂ can replace carbohydrates as signals. Moreover, a cross-talk exists between genes associated with the regulation of starch and lipid metabolism. The involvement of genes responding to phytohormones in HL acclimation appears to be less likely. Various candidate genes involved in retrograde control of nuclear gene expression emerged from the analyses of global gene expression.
authors: Department of Botany II, Cologne Biocenter, University of Cologne, Zülpicher Straße 47b, D-50674 Cologne, Germany.
authors: Jessica
authors: J
authors: Schmitz
authors: Luisa
authors: L
authors: Heinrichs
authors: Federico
authors: F
authors: Scossa
authors: Alisdair R
authors: AR
authors: Fernie
authors: Marie-Luise
authors: ML
authors: Oelze
authors: Karl-Josef
authors: KJ
authors: Dietz
authors: Maxi
authors: M
authors: Rothbart
authors: Bernhard
authors: B
authors: Grimm
authors: Ulf-Ingo
authors: UI
authors: Flügge
authors: Rainer E
authors: RE
authors: Häusler
mesh_terms: D000064:Acclimatization; D017360:Arabidopsis / Q000235:genetics / Q000502:physiology* / Q000528:radiation effects; D001692:Biological Transport; D050260:Carbohydrate Metabolism; D002244:Carbon / Q000378:metabolism*; D002736:Chloroplasts / Q000378:metabolism; D015536:Down-Regulation; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D005947:Glucose / Q000378:metabolism; D008027:Light; D055432:Metabolomics; D009154:Mutation; D020411:Oligonucleotide Array Sequence Analysis; D010788:Photosynthesis; D018515:Plant Leaves / Q000235:genetics / Q000502:physiology / Q000528:radiation effects; D017382:Reactive Oxygen Species / Q000378:metabolism*; D015398:Signal Transduction; D059467:Transcriptome; D015854:Up-Regulation
chemical_list: D017382:Reactive Oxygen Species; D002244:Carbon; D005947:Glucose
keywords: Arabidopsis mutants; carbon partitioning; light acclimation; metabolomics; photosynthesis; retrograde signalling; sugar metabolism; transcriptomics.