This Article Full Text Full Text (PDF) Supplemental Data All Versions of this Article: 149/1/515    most recent pp.108.128124v1 Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via Web of Science (1) Citing Articles via Google Scholar Google Scholar Articles by Häusler, R. E. Articles by Flügge, U.-I. Search for Related Content PubMed PubMed Citation Articles by Häusler, R. E. Articles by Flügge, U.-I. Agricola Articles by Häusler, R. E. Articles by Flügge, U.-I.

BIOENERGETICS AND PHOTOSYNTHESIS

Chlororespiration and Grana Hyperstacking: How an Arabidopsis Double Mutant Can Survive Despite Defects in Starch Biosynthesis and Daily Carbon Export from Chloroplasts^1,[W]

Universität zu Köln, Botanisches Institut, D–50931 Cologne, Germany (R.E.H., H.H.K., J.S., K.B., S.H., A.G., U.-I.F.); Universität Bayreuth, Biologie/Elektronenmikroskopie NW I/B1, D–95440 Bayreuth, Germany (S.G.); and Universität Bonn, Institut für Molekulare Physiologie und Biotechnologie der Pflanzen, D–53115 Bonn, Germany (P.D.)

An Arabidopsis (Arabidopsis thaliana) double mutant impaired in starch biosynthesis and the triose phosphate/phosphate translocator (adg1-1/tpt-1) is characterized by a diminished utilization of photoassimilates and the concomitant consumption of reducing power and energy produced in the photosynthetic light reaction. In order to guarantee survival, the double mutant responds to this metabolic challenge with growth retardation, an 80% decline in photosynthetic electron transport, diminished chlorophyll contents, an enhanced reduction state of plastoquinone in the dark (up to 50%), a perturbation of the redox poise in leaves (increased NADPH/NADP ratios and decreased ascorbate/dehydroascorbate ratios), hyperstacking of grana thylakoids, and an increased number of plastoglobules. Enhanced oxygen consumption and applications of inhibitors of alternative mitochondrial and chloroplast oxidases (AOX and PTOX) suggest that chlororespiration as well as mitochondrial respiration are involved in the enhanced plastoquinone reduction state in the dark. Transcript amounts of PTOX and AOX were diminished and nucleus-encoded components related to plastidic NADH reductase (NDH1) were increased in adg1-1/tpt-1 compared with the wild type. Cytochrome b₅₅₉, proposed to be involved in the reoxidation of photosystem II, was not regulated at the transcriptional level. The hyperstacking of grana thylakoids mimics adaptation to low light, and increased plastoglobule numbers suggest a response to enhanced oxidative stress. Altered chloroplast organization combined with perturbations in the redox poise suggests that adg1-1/tpt-1 could be a tool for the in vivo study of retrograde signaling mechanisms controlling the coordinated expression of nucleus- and plastome-encoded photosynthetic genes.

The author responsible for distribution of materials integral to the findings presented in this article in accordance with the policy described in the Instructions for Authors (www.plantphysiol.org) is: Rainer E. Häusler (rainer.haeusler{at}uni-koeln.de).

^[W] The online version of this article contains Web-only data.

www.plantphysiol.org/cgi/doi/10.1104/pp.108.128124

^* Corresponding author; e-mail rainer.haeusler{at}uni-koeln.de.

Received August 15, 2008; accepted October 26, 2008; published October 31, 2008.

This article has been cited by other articles:

				K. Brautigam, L. Dietzel, T. Kleine, E. Stroher, D. Wormuth, K.-J. Dietz, D. Radke, M. Wirtz, R. Hell, P. Dormann, et al. Dynamic Plastid Redox Signals Integrate Gene Expression and Metabolism to Induce Distinct Metabolic States in Photosynthetic Acclimation in Arabidopsis PLANT CELL, September 1, 2009; 21(9): 2715 - 2732. [Abstract] [Full Text] [PDF]