Uptake and incorporation of iron in sugar beet chloroplasts

Ádám Solti, Krisztina Kovács, Brigitta Basa, Attila Vértes, Éva Sárvári, Ferenc Fodor

Research output: Contribution to journalArticle

21 Citations (Scopus)

Abstract

Chloroplasts contain 80-90% of iron taken up by plant cells. Though some iron transport-related envelope proteins were identified recently, the mechanism of iron uptake into chloroplasts remained unresolved. To shed more light on the process of chloroplast iron uptake, trials were performed with isolated intact chloroplasts of sugar beet (Beta vulgaris). Iron uptake was followed by measuring the iron content of chloroplasts in the form of ferrous-bathophenantroline-disulphonate complex after solubilising the chloroplasts in reducing environment. Ferric citrate was preferred to ferrous citrate as substrate for chloroplasts. Strong dependency of ferric citrate uptake on photosynthetic electron transport activity suggests that ferric chelate reductase uses NADPH, and is localised in the inner envelope membrane. The Km for iron uptake from ferric-citrate pool was 14.65±3.13μM Fe(III)-citrate. The relatively fast incorporation of 57Fe isotope into Fe-S clusters/heme, detected by Mössbauer spectroscopy, showed the efficiency of the biosynthetic machinery of these cofactors in isolated chloroplasts. The negative correlation between the chloroplast iron concentration and the rate of iron uptake refers to a strong feedback regulation of the uptake.

Original languageEnglish
Pages (from-to)91-97
Number of pages7
JournalPlant Physiology and Biochemistry
Volume52
DOIs
Publication statusPublished - Mar 1 2012

Keywords

  • Bathophenantroline disulphonate
  • Beta vulgaris (sugar beet)
  • Chloroplast
  • Ferric citrate
  • Iron uptake
  • Mössbauer spectroscopy

ASJC Scopus subject areas

  • Physiology
  • Genetics
  • Plant Science

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