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First published online August 27, 2004; 10.1104/pp.104.046698 Plant Physiology 136:2710-2721 (2004) © 2004 American Society of Plant Biologists
Light Regulation of the Arabidopsis Respiratory Chain. Multiple Discrete Photoreceptor Responses Contribute to Induction of Type II NAD(P)H Dehydrogenase Genes1Lund University Department of Cell and Organism Biology, SE22362 Lund, Sweden (M.A.E., A.G.R.); University of Leicester Department of Biology, Leicester LE1 7RH, United Kingdom (K.A.F., M.G.S., G.C.W.); and The Royal Veterinary and Agricultural University Department of Plant Biology, DK1871 Frederiksberg C, Denmark (Å.S.S.)
Controlled oxidation reactions catalyzed by the large, proton-pumping complexes of the respiratory chain generate an electrochemical gradient across the mitochondrial inner membrane that is harnessed for ATP production. However, several alternative respiratory pathways in plants allow the maintenance of substrate oxidation while minimizing the production of ATP. We have investigated the role of light in the regulation of these energy-dissipating pathways by transcriptional profiling of the alternative oxidase, uncoupling protein, and type II NAD(P)H dehydrogenase gene families in etiolated Arabidopsis seedlings. Expression of the nda1 and ndc1 NAD(P)H dehydrogenase genes was rapidly up-regulated by a broad range of light intensities and qualities. For both genes, light induction appears to be a direct transcriptional effect that is independent of carbon status. Mutant analyses demonstrated the involvement of two separate photoreceptor families in nda1 and ndc1 light regulation: the phytochromes (phyA and phyB) and an undetermined blue light photoreceptor. In the case of the nda1 gene, the different photoreceptor systems generate distinct kinetic induction profiles that are integrated in white light response. Primary transcriptional control of light response was localized to a 99-bp region of the nda1 promoter, which contains an I-box flanked by two GT-1 elements, an arrangement prevalent in the promoters of photosynthesis-associated genes. Light induction was specific to nda1 and ndc1. The only other substantial light effect observed was a decrease in aox2 expression. Overall, these results suggest that light directly influences the respiratory electron transport chain via photoreceptor-mediated transcriptional control, likely for supporting photosynthetic metabolism.
1 This work was supported by the Swedish Research Council for Environment, Agricultural Sciences, and Spatial Planning, by Carl Tesdorpfs Stiftelse, and by the Wenner-Gren Foundations (fellowship to M.A.E.). Article, publication date, and citation information can be found at www.plantphysiol.org/cgi/doi/10.1104/pp.104.046698. * Corresponding author; e-mail allan.rasmusson{at}cob.lu.se; fax 46462224113. Received May 19, 2004; returned for revision June 23, 2004; accepted July 4, 2004. This article has been cited by other articles:
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