Identification of a functional respiratory complex in chloroplasts through analysis of tobacco mutants containing disrupted plastid ndh genes Journal Article


Author(s): Burrows, Paul A; Sazanov, Leonid A; Sváb, Zóra ; Maliga, Pàl; Nixon, Peter J
Article Title: Identification of a functional respiratory complex in chloroplasts through analysis of tobacco mutants containing disrupted plastid ndh genes
Affiliation
Abstract: The plastid genomes of several plants contain homologues, termed ndh genes, of genes encoding subunits of the NADH:ubiquinone oxidoreductase or complex I of mitochondria and eubacteria. The functional significance of the Ndh proteins in higher plants is uncertain. We show here that tobacco chloroplasts contain a protein complex of 550 kDa consisting of at least three of the ndh gene products: NdhI, NdhJ and NdhK. We have constructed mutant tobacco plants with disrupted ndhC, ndhK and ndhJ plastid genes, indicating that the Ndh complex is dispensible for plant growth under optimal growth conditions. Chlorophyll fluorescence analysis shows that in vivo the Ndh complex catalyses the post-illumination reduction of the plastoquinone pool and in the light optimizes the induction of photosynthesis under conditions of water stress. We conclude that the Ndh complex catalyses the reduction of the plastoquinone pool using stromal reductant and so acts as a respiratory complex. Overall, our data are compatible with the participation of the Ndh complex in cyclic electron flow around the photosystem I complex in the light and possibly in a chloroplast respiratory chain in the dark.
Keywords: Chloroplast; Chlororespiration; Cyclic electron flow; Ndh; Plastid mutant
Journal Title: EMBO Journal
Volume: 17
Issue 4
ISSN: 1460-2075
Publisher: Wiley-Blackwell  
Date Published: 1998-02-04
Start Page: 868
End Page: 876
Sponsor: the work was supported by grants from the BBSRC, The Royal Society (to P.J.N.) and The National Science Foundation (to P.M.).
URL:
DOI: 10.1093/emboj/17.4.868
Open access: yes (repository)