D-2-hydroxyglutarate metabolism is linked to photorespiration in the shm1-1 mutant
Artikel i vetenskaplig tidskrift, 2013

The Arabidopsis mutant shm1-1 is defective in mitochondrial serine hydroxymethyltransferase 1 activity and displays a lethal photorespiratory phenotype at ambient CO2 concentration but grows normally at high CO2. After transferring high CO2-grown shm1-1 plants to ambient CO2, the younger leaves remain photosynthetically active while developed leaves display increased yellowing and decreased FV/FM values. Metabolite analysis of plants transferred from high CO2 to ambient air indicates a massive light-dependent (photorespiratory) accumulation of glycine, 2-oxoglutarate (2OG) and D-2-hydroxyglutarate (D-2HG). Amino acid markers of senescence accumulated in ambient air in wild-type and shm1-1 plants maintained in darkness and also build up in shm1-1 in the light. This, together with an enhanced transcription of the senescence marker SAG12 in shm1-1, suggests the initiation of senescence in shm1-1 under photorespiratory conditions. Mitochondrial D-2HG dehydrogenase (D-2HGDH) converts D-2HG into 2OG. In vitro studies indicate that 2OG exerts competitive inhibition on D-2HGDH with a Ki of 1.96 mm. 2OG is therefore a suitable candidate as inhibitor of the in vivo D-2HGDH activity, as 2OG is produced and accumulates in mitochondria. Inhibition of the D-2HGDH by 2OG is likely a mechanism by which D-2HG accumulates in shm1-1, however it cannot be ruled out that D-2HG may also accumulate due to an active senescence programme that is initiated in these plants after transfer to photorespiratory conditions. Thus, a novel interaction of the photorespiratory pathway with cellular processes involving D-2HG has been identified.

Serine hydroxymethyltransferase (SHMT)



2-hydroxyglutarate (2HG)


A. Kuhn

Universität zu Köln

Martin Engqvist

California Institute of Technology (Caltech)

Universität zu Köln

E.E.W. Jansen

VU University Medical Center

A.P.M. Weber

Heinrich Heine Universität Düsseldorf

C. Jakobs

Heinrich Heine Universität Düsseldorf

V.G. Maurino

Universität zu Köln

California Institute of Technology (Caltech)

Plant Biology

1435-8603 (ISSN)

Vol. 15 4 776-784



Biokemi och molekylärbiologi



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