Archives of Microbiology

, Volume 183, Issue 1, pp 19–26

Phylogeny of symbiotic cyanobacteria within the genus Nostoc based on 16S rDNA sequence analyses

  • Mette M. Svenning
  • Torsten Eriksson
  • Ulla Rasmussen
Original Paper

DOI: 10.1007/s00203-004-0740-y

Cite this article as:
Svenning, M.M., Eriksson, T. & Rasmussen, U. Arch Microbiol (2005) 183: 19. doi:10.1007/s00203-004-0740-y


A phylogenetic analysis of selected symbiotic Nostoc strain sequences and available database 16S rDNA sequences of both symbiotic and free-living cyanobacteria was carried out using maximum likelihood and Bayesian inference techniques. Most of the symbiotic strains fell into well separated clades. One clade consisted of a mixture of symbiotic and free-living isolates. This clade includes Nostoc sp. strain PCC 73102, the reference strain proposed for Nostoc punctiforme. A separate symbiotic clade with isolates exclusively from Gunnera species was also obtained, suggesting that not all symbiotic Nostoc species can be assigned to N. punctiforme. Moreover, isolates from Azolla filiculoides and one from Gunnera dentata were well nested within a clade comprising most of the Anabaena sequences. This result supports the affiliation of the Azolla isolates with the genus Anabaena and shows that strains within this genus can form symbioses with additional hosts. Furthermore, these symbiotic strains produced hormogonia, thereby verifying that hormogonia formation is not absent in Anabaena and cannot be used as a criterion to distinguish it from Nostoc.


CyanobacteriaNostocAnabaenaSymbioses16S rRNA geneSequencingPhylogeny

Copyright information

© Springer-Verlag 2004

Authors and Affiliations

  • Mette M. Svenning
    • 1
  • Torsten Eriksson
    • 2
  • Ulla Rasmussen
    • 3
  1. 1.Department of Biology, Faculty of ScienceUniversity of TromsöTromsöNorway
  2. 2.Bergius FoundationRoyal Swedish Academy of SciencesStockholmSweden
  3. 3.Department of BotanyStockholm UniversityStockholmSweden