Light regulation of the Arabidopsis respiratory chain. Multiple discrete photoreceptor responses contribute to induction of type II NAD(P)H dehydrogenase genes.
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.
Escobar
Matthew A
MA
Lund University Department of Cell and Organism Biology, SE-22362 Lund, Sweden.
Franklin
Keara A
KA
Svensson
A Staffan
AS
Salter
Michael G
MG
Whitelam
Garry C
GC
Rasmusson
Allan G
AG
D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism* / Q000528:radiation effects*; D029681:Arabidopsis Proteins; D001483:Base Sequence; D018744:DNA, Plant / Q000235:genetics; D004579:Electron Transport / Q000235:genetics / Q000528:radiation effects*; D015971:Gene Expression Regulation, Enzymologic; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D005966:Glucuronidase / Q000235:genetics; D008027:Light; D008969:Molecular Sequence Data; D009247:NADH, NADPH Oxidoreductases / Q000235:genetics*; D010786:Photoreceptor Cells / Q000378:metabolism; D045322:Photosynthetic Reaction Center Complex Proteins / Q000528:radiation effects*; D010834:Phytochrome / Q000235:genetics / Q000378:metabolism; D051942:Phytochrome A; D051939:Phytochrome B; D030821:Plants, Genetically Modified; D011401:Promoter Regions, Genetic; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
D029681:Arabidopsis Proteins; D018744:DNA, Plant; C497973:PHYA protein, Arabidopsis; C497952:PHYB protein, Arabidopsis; D045322:Photosynthetic Reaction Center Complex Proteins; D051942:Phytochrome A; D014157:Transcription Factors; D010834:Phytochrome; D051939:Phytochrome B; D009247:NADH, NADPH Oxidoreductases; D005966:Glucuronidase