Previous Article | Next Article ![]()
Journal of Bacteriology, September 2008, p. 5824-5831, Vol. 190, No. 17
0021-9193/08/$08.00+0 doi:10.1128/JB.00524-08
Copyright © 2008, American Society for Microbiology. All Rights Reserved.

Laurie Vuillet,1,
Laure Hannibal,1
Jean-Marc Adriano,2,3,4
Joël Fardoux,1
Pierre Bouyer,2,3,4
Katia Bonaldi,1
Darrell Fleischman,5
Eric Giraud,1 and
André Verméglio2,3,4*
Laboratoire des Symbioses Tropicales et Méditerranéennes, IRD, CIRAD, AGRO-M, INRA, UM2, TA A-82/J, Campus de Baillarguet, 34398 Montpellier Cedex 5, France,1 CEA, DSV, IBEB, Lab Bioenerget Cellulaire, Saint-Paul-lez-Durance, F-13108, France,2 CNRS, UMR Biologie Vegetale & Microbiologie Environnementale, Saint-Paul-lez-Durance F-13108, France,3 Aix-Marseille Université, Saint-Paul-lez-Durance F-13108, France,4 Department of Biochemistry and Molecular Biology, Wright State University, Dayton, Ohio 454355
Received 17 April 2008/ Accepted 23 June 2008
The recent sequence analysis of the photosynthetic and plant-symbiotic Bradyrhizobium sp. strain BTAi1 revealed the unexpected presence of a pucBA operon encoding the apoproteins of peripheral light-harvesting (LH) complexes. This pucBA operon is found close to a bacteriophytochrome gene (BphP3B BTAi1) and a two-component transcriptional regulator gene (TFBTAi1 gene). In this study, we show that BphP3B BTAi1 acts as a bona fide bacteriophytochrome and controls, according to light conditions, the expression of the pucBA operon found in its vicinity. This light regulatory pathway is very similar to the one previously described for chromo-BphP4Rp in Rhodopseudomonas palustris and conducts the synthesis of a peripheral LH complex. This LH complex presents a single absorption band at low temperature, centered at 803 nm. Fluorescence emission analysis of intact cells indicates that this peripheral LH complex does not act as an efficient light antenna. One putative function of this LH complex could be to evacuate excess light energy in order to protect Bradyrhizobium strain BTAi1, an aerobic anoxygenic photosynthetic bacterium, against photooxidative damage during photosynthesis.
Published ahead of print on 7 July 2008.
These authors contributed equally.
Copyright © 2009 by the American Society for Microbiology. For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»