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D-2-hydroxyglutarate metabolism is linked to photorespiration in the shm1-1 mutant

A. Kuhn ; Martin Engqvist (Institutionen för kemi- och bioteknik, Systembiologi) ; E.E.W. Jansen ; C. Jakobs ; A.P.M. Weber ; V.G. Maurino
Plant Biology (1435-8603). Vol. 15 (2013), 4, p. 776-784.
[Artikel, refereegranskad vetenskaplig]

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.

Nyckelord: 2-hydroxyglutarate (2HG) , Photorespiration , Senescence , Serine hydroxymethyltransferase (SHMT)



Denna post skapades 2017-02-13.
CPL Pubid: 248109

 

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Institutioner (Chalmers)

Institutionen för kemi- och bioteknik, Systembiologi (2008-2014)

Ämnesområden

Molekylärbiologi
Botanik

Chalmers infrastruktur