Molecular and General Genetics MGG

, Volume 222, Issue 2, pp 425–430

Structure of the Rubisco operon from the unicellular red algaCyanidium caldarium: Evidence for a polyphyletic origin of the plastids

  • Klaus Valentin
  • Klaus Zetsche

DOI: 10.1007/BF00633849

Cite this article as:
Valentin, K. & Zetsche, K. Mol Gen Genet (1990) 222: 425. doi:10.1007/BF00633849


The genes for both subunits of ribulose-1,5-bisphosphate-carboxylase/oxygenase (Rubisco) were located on the plastid DNA (ptDNA) of the unicellular red algaCyanidium caldarium. Both genes are organized together in an operon. The sequence homology of both genes to the corresponding genes from the unicellular red algaPorphyridium aerugineum is remarkably high, whereas homology to Rubisco genes from chloroplasts and two recent cyanobacteria is significantly lower. These data provide strong evidence for a polyphyletic origin of chloroplasts and rhodoplasts. In addition the genes for the small subunit of Rubisco (rbcS) from red algae show about 60% homology torbcS genes from cryptophytes and chromophytes. Thus, homologies in therbcS gene indicate a close phylogenetic relationship between rhodoplasts and the plastids of Chromophyta.

Key words

Endosymbiosis Plastid evolution Ribulose-1,5-bisphosphate carboxylase Rhodophyta 

Copyright information

© Springer-Verlag 1990

Authors and Affiliations

  • Klaus Valentin
    • 1
  • Klaus Zetsche
    • 1
  1. 1.Institut für PflanzenphysiologieJustus-Liebig-UniversitätGiessenGermany

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