Open AccessMitochondrial uncoupling protein is required for efficient photosynthesis
Author(s) -
Lee Sweetlove,
Anna Lytovchenko,
Megan Morgan,
Adriano NunesNesi,
Nicolas L. Taylor,
Charles Baxter,
Ira Eickmeier,
Alisdair R. Fernie
Publication year - 2006
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.0607751103
Subject(s) - photorespiration , photosynthesis , arabidopsis , biochemistry , atp synthase , biology , electron transport chain , uncoupling protein , mitochondrion , inner mitochondrial membrane , chemiosmosis , oxidative phosphorylation , microbiology and biotechnology , thylakoid , biophysics , chloroplast , mutant , gene , brown adipose tissue , adipose tissue
Uncoupling proteins (UCPs) occur in the inner mitochondrial membrane and dissipate the proton gradient across this membrane that is normally used for ATP synthesis. Although the catalytic function and regulation of plant UCPs have been described, the physiological purpose of UCP in plants has not been established. Here, biochemical and physiological analyses of an insertional knockout of one of theArabidopsis UCP genes (AtUCP1 ) are presented that resolve this issue. Absence of UCP1 results in localized oxidative stress but does not impair the ability of the plant to withstand a wide range of abiotic stresses. However, absence of UCP1 results in a photosynthetic phenotype. Specifically there is a restriction in photorespiration with a decrease in the rate of oxidation of photorespiratory glycine in the mitochondrion. This change leads to an associated reduced photosynthetic carbon assimilation rate. Collectively, these results suggest that the main physiological role of UCP1 inArabidopsis leaves is related to maintaining the redox poise of the mitochondrial electron transport chain to facilitate photosynthetic metabolism.