Stimulation of respiration and nitrogenase in bacteroids of Siratro (Macroptilium atropurpureum) by plant nodule cytosol

Michael K. Udvardi, David A. Day, Peter M. Gresshoff

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)

Abstract

Nitrogenase activity (acetylene reduction) of isolated Siratro (Macroptilium atropurpureum) bacteroids was stimulated by addition of plant cytosol fractions which also preserved activity at high (up to 3%) O2 tensions. These effects were not due to leghaemoglobin. Boiling removed some, but not all, of the protective capacity of the cytosol. Heat treated cytosol substantially stimulated the respiration of siratro bacteroids. Of a wide variety of compounds tested, only ascorbate could mimic the cytosol. Ascorbate was present in the cytosol fraction, in significant quantities. The effect of ascorbate was evident at low O2 concentrations and in purified bacteroids, and was inhibited by cyanide. Siratro bacteroids appear to possess an oxidase which could serve a protective role in vivo.

Original languageEnglish
Pages (from-to)207-209
Number of pages3
JournalPlant Cell Reports
Volume5
Issue number3
DOIs
Publication statusPublished - Jun 1986
Externally publishedYes

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