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Suppression of the external mitochondrial NADPH dehydrogenase, NDB1, in Arabidopsis thaliana affects central metabolism and vegetative growth.

Author:
  • Sabá Wallström
  • Igor Florez-Sarasa
  • Wagner L Araújo
  • Mari Aidemark
  • María Fernández Fernández
  • Alisdair R Fernie
  • Miquel Ribas-Carbó
  • Allan G. Rasmusson
Publishing year: 2014
Language: English
Pages: 356-368
Publication/Series: Molecular Plant
Volume: 7
Issue: 2
Document type: Journal article
Publisher: Oxford University Press

Abstract english

Ca(2+)-dependent oxidation of cytosolic NADPH is mediated by NDB1, which is an external type II NADPH dehydrogenase in the plant mitochondrial electron transport chain. Using RNA interference, the NDB1 transcript was suppressed by 80% in Arabidopsis thaliana plants, and external Ca(2+)-dependent NADPH dehydrogenase activity became undetectable in isolated mitochondria. This was linked to a decreased level of NADP+ in rosettes of the transgenic lines. Sterile-grown transgenic seedlings displayed decreased growth specifically on glucose, and respiratory metabolism of (14)C-glucose was increased. On soil, NDB1-suppressing plants had a decreased vegetative biomass, but leaf maximum quantum efficiency of photosystem II and CO2 assimilation rates, as well as total respiration were similar to the wild type. The in vivo alternative oxidase activity and capacity were also similar in all genotypes. Metabolic profiling revealed decreased levels of sugars, citric acid cycle intermediates and amino acids in the transgenic lines. The NDB1-suppression induced transcriptomic changes associated with protein synthesis and glucosinolate and jasmonate metabolism. The transcriptomic changes also overlapped with changes observed in a mutant lacking ABAINSENSITIVE4 and in A. thaliana overexpressing stress tolerance genes from rice. The results thus indicate that A. thaliana NDB1 modulates NADP(H) reduction levels, which in turn affect central metabolism and growth, and interact with defence signalling.

Keywords

  • Biological Sciences
  • vegetative growth.
  • type II NAD(P)H dehydrogenase
  • citric acid cycle
  • metabolic profiling
  • mitochondrial respiration
  • NADPH
  • RNA interference

Other

Published
  • ISSN: 1752-9867
Allan Rasmusson
E-mail: allan [dot] rasmusson [at] biol [dot] lu [dot] se

Professor

Molecular Cell Biology

+46 46 222 93 81

B-A329A

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