SLO2, a mitochondrial pentatricopeptide repeat protein affecting several RNA editing sites, is required for energy metabolism

Qiang Zhu, Jasper Dugardeyn, Chunyi Zhang, Mizuki Takenaka, Kristina Kühn, Christian Craddock, Jan Smalle, Michael Karampelias, Jurgen Denecke, Janny Peters, Tom Gerats, Axel Brennicke, Peter Eastmond, Etienne H. Meyer, Dominique Van Der Straeten

Research output: Contribution to journalArticlepeer-review

96 Scopus citations


Pentatricopeptide repeat (PPR) proteins belong to a family of approximately 450 members in Arabidopsis, of which few have been characterized. We identified loss of function alleles of SLO2, defective in a PPR protein belonging to the E+ subclass of the P-L-S subfamily. slo2 mutants are characterized by retarded leaf emergence, restricted root growth, and late flowering. This phenotype is enhanced in the absence of sucrose, suggesting a defect in energy metabolism. The slo2 growth retardation phenotypes are largely suppressed by supplying sugars or increasing light dosage or the concentration of CO2. The SLO2 protein is localized in mitochondria. We identified four RNA editing defects and reduced editing at three sites in slo2 mutants. The resulting amino acid changes occur in four mitochondrial proteins belonging to complex I of the electron transport chain. Both the abundance and activity of complex I are highly reduced in the slo2 mutants, as well as the abundance of complexes III and IV. Moreover, ATP, NAD+, and sugar contents were much lower in the mutants. In contrast, the abundance of alternative oxidase was significantly enhanced. We propose that SLO2 is required for carbon energy balance in Arabidopsis by maintaining the abundance and/or activity of complexes I, III, and IV of the mitochondrial electron transport chain.

Original languageEnglish
Pages (from-to)836-849
Number of pages14
JournalPlant Journal
Issue number5
StatePublished - Sep 2012


  • Arabidopsis thaliana
  • RNA editing
  • growth retardation
  • mitochondria
  • mitochondrial electron transport chain
  • pentatricopeptide repeat

ASJC Scopus subject areas

  • Genetics
  • Plant Science
  • Cell Biology


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