Influence of chloroplastic photo-oxidative stress on mitochondrial alternative oxidase capacity and respiratory properties: A case study with arabidopsis yellow variegated 2

Keisuke Yoshida, Chihiro Watanabe, Yusuke Kato, Wataru Sakamoto, Ko Noguchi

Research output: Contribution to journalArticle

55 Citations (Scopus)

Abstract

Mitochondrial alternative oxidase (AOX), the unique respiratory terminal oxidase in plants, catalyzes the energy-wasteful cyanide (CN)-resistant respiration. Although it has been demonstrated that leaf AOX is up-regulated under high-light (HL) conditions, the in vivo mechanism of AOX up-regulation by light is still unknown. In the present study, we examined whether the photo-oxidative stress in the chloroplast modulates mitochondrial respiratory properties, especially the AOX capacity, using Arabidopsis leaf-variegated mutant yellow variegated 2 (var2) and exposing plants to HL. var2 mutants lack FtsH2 metalloprotease required for the repair of damaged PSII. Indeed, var2-1 suffered from photo-oxidative stress even before the HL treatments. While the activities of tricarboxylic acid cycle enzymes and cytochrome c oxidase in var2-1 were almost identical to those in the wild type, the amount of AOX protein and the CN-resistant respiration rate were higher in var2-1. Real-time PCR analysis revealed that HL treatment induced the expression of some energy-dissipating respiratory genes, including AOX1a, NDB2 and UCP5, more strongly in var2-1. Western blotting using var2-1 leaf extracts specific to green or white sectors, containing functional or non-functional photosynthetic apparatus, respectively, revealed that more AOX protein was induced in the green sectors by the HL treatment. These results indicate that photo-oxidative stress by excess light is involved in the regulation of respiratory gene expression and the modulation of respiratory properties, especially the AOX up-regulation.

Original languageEnglish
Pages (from-to)592-603
Number of pages12
JournalPlant and Cell Physiology
Volume49
Issue number4
DOIs
Publication statusPublished - Apr 1 2008

Keywords

  • Alternative oxidase
  • Arabidopsis thaliana
  • Energy-dissipating respiration
  • Photo-oxidative stress
  • Yellow variegated 2

ASJC Scopus subject areas

  • Physiology
  • Plant Science
  • Cell Biology

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