Arabidopsis SIZ1 positively regulates alternative respiratory bypass pathways

Bong Soo Park, Sung Il Kim, Jong Tae Song, Hak Soo Seo

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


Plant mitochondria possess alternative respiratory pathways mediated by the type II NAD(P)H dehydrogenases and alternative oxidases. Here, E3 SUMO ligase was shown to regulate alternative respiratory pathways and to participate in the maintenance of carbon and nitrogen balance in Arabidopsis. The transcript abundance of the type II NAD(P)H dehydrogenases NDA2 and NDB2 and alternative oxidases AOX1a and AOX1d genes was low in siz1-2 mutants compared to that in wild-type. The addition of nitrate or ammonium resulted in a decrease or an increase in the expression of the same gene families, respectively, in both wild-type and siz1-2 mutants. The amount of free sugar (glucose, fructose and sucrose) was lower in siz1-2 mutants than that in wild-type. These results indicate that low nitrate reductase activity due to the AtSIZ1 mutation is correlated with an overall decrease in alternative respiration and with a low carbohydrate content to maintain the carbon to nitrogen ratio in siz1-2 mutants.

Original languageEnglish (US)
Pages (from-to)342-347
Number of pages6
JournalBMB Reports
Issue number6
StatePublished - Jun 2012


  • Alternative respiration
  • AtSIZ1
  • Carbon to nitrogen ratio
  • E3 SUMO ligase
  • Nitrate reductase

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology


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