D‐2‐hydroxyglutarate metabolism is linked to photorespiration in the shm1‐1 mutant. (2nd April 2013)

• Record Type: Journal Article
• Authors: Kuhn, A.; Engqvist, M. K. M.; Jansen, E. E. W.; Weber, A. P. M.; Jakobs, C.; Maurino, V. G.; Rennenberg, H.
• Is Part Of: Plant biology. Volume 15:Number 4(2013:Jul.)
• Page Start: 776
• Page End: 784
• Publication Date: 2013-04-02
• Subjects: Botany -- Periodicals; Plants -- genetics -- Periodicals; Plants -- growth & development -- Periodicals; Plant Proteins -- Periodicals; Gene Expression Regulation, Plant -- Periodicals; Botanique -- Périodiques; 580
• DOI: 10.1111/plb.12020
• Languages: English
• ISSNs: 1435-8603

Abstract

<abstract abstract-type="main" xml:lang="en" id="plb12020-abs-0001"> <title>Abstract</title> <p>The Arabidopsis mutant <italic>shm1‐1</italic> is defective in mitochondrial serine hydroxymethyltransferase 1 activity and displays a lethal photorespiratory phenotype at ambient CO<sub>2</sub> concentration but grows normally at high CO<sub>2</sub>. After transferring high CO<sub>2</sub>‐grown <italic>shm1‐1</italic> plants to ambient CO<sub>2</sub>, the younger leaves remain photosynthetically active while developed leaves display increased yellowing and decreased F<sub>V</sub>/F<sub>M</sub> values. Metabolite analysis of plants transferred from high CO<sub>2</sub> 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 <italic>shm1‐1</italic> plants maintained in darkness and also build up in <italic>shm1‐1</italic> in the light. This, together with an enhanced transcription of the senescence marker SAG12 in <italic>shm1‐1</italic>, suggests the initiation of senescence in <italic>shm1‐1</italic> under photorespiratory conditions. Mitochondrial D‐2HG dehydrogenase (D‐2HGDH) converts D‐2HG into 2OG. <italic>In vitro</italic> studies indicate that 2OG exerts competitive inhibition on D‐2HGDH with a <italic>K</italic><sub>i</sub> of 1.96 m<sc>m</sc>. 2OG is therefore a suitable candidate as inhibitor of the <italic>in vivo </italic>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 <italic>shm1‐1</italic>, 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.</p> </abstract>