eCite Digital Repository

Mitochondrial malate dehydrogenase lowers leaf respiration and alters photorespiration and plant growth in Arabidopsis

Citation

Tomaz, T and Bagard, M and Pracharoenwattana, I and Linden, P and Lee, CP and Carroll, AJ and Stroher, E and Smith, SM and Gardestrom, P and Millar, AH, Mitochondrial malate dehydrogenase lowers leaf respiration and alters photorespiration and plant growth in Arabidopsis, Plant Physiology, 154, (3) pp. 1143-1157. ISSN 0032-0889 (2010) [Refereed Article]


Preview
PDF
Pending copyright assessment - Request a copy
1Mb
  

Copyright Statement

2010 American Society of Plant Biologists

DOI: doi:10.1104/pp.110.161612

Abstract

Malate dehydrogenase (MDH) catalyzes a reversible NAD+-dependent-dehydrogenase reaction involved in central metabolism and redox homeostasis between organelle compartments. To explore the role of mitochondrial MDH (mMDH) in Arabidopsis (Arabidopsis thaliana), knockout single and double mutants for the highly expressed mMDH1 and lower expressed mMDH2 isoforms were constructed and analyzed. A mmdh1mmdh2 mutant has no detectable mMDH activity but is viable, albeit small and slow growing. Quantitative proteome analysis of mitochondria shows changes in other mitochondrial NAD-linked dehydrogenases, indicating a reorganization of such enzymes in the mitochondrial matrix. The slow-growing mmdh1mmdh2 mutant has elevated leaf respiration rate in the dark and light, without loss of photosynthetic capacity, suggesting that mMDH normally uses NADH to reduce oxaloacetate to malate, which is then exported to the cytosol, rather than to drive mitochondrial respiration. Increased respiratory rate in leaves can account in part for the low net CO2 assimilation and slow growth rate of mmdh1mmdh2. Loss of mMDH also affects photorespiration, as evidenced by a lower postillumination burst, alterations in CO2 assimilation/intercellular CO2 curves at low CO2, and the light-dependent elevated concentration of photorespiratory metabolites. Complementation of mmdh1mmdh2 with an mMDH cDNA recovered mMDH activity, suppressed respiratory rate, ameliorated changes to photorespiration, and increased plant growth. A previously established inverse correlation between mMDH and ascorbate content in tomato (Solanum lycopersicum) has been consolidated in Arabidopsis and may potentially be linked to decreased galactonolactone dehydrogenase content in mitochondria in the mutant. Overall, a central yet complex role for mMDH emerges in the partitioning of carbon and energy in leaves, providing new directions for bioengineering of plant growth rate and a new insight into the molecular mechanisms linking respiration and photosynthesis in plants.

Item Details

Item Type:Refereed Article
Keywords:malate dehydrogenase, mitochondria, photorespiration, arabidopsis thaliana, leaf respiration, enzyme
Research Division:Biological Sciences
Research Group:Plant Biology
Research Field:Plant Physiology
Objective Division:Expanding Knowledge
Objective Group:Expanding Knowledge
Objective Field:Expanding Knowledge in the Biological Sciences
Author:Smith, SM (Professor Steven Smith)
ID Code:101468
Year Published:2010
Web of Science® Times Cited:85
Deposited By:Plant Science
Deposited On:2015-06-24
Last Modified:2017-11-23
Downloads:0

Repository Staff Only: item control page