, Volume 438, Issue 1, pp 99–105

Taxonomic re-evaluation of Aphanizomenon flos-aquae NH-5 based on morphology and 16S rRNA gene sequences


  • Renhui Li
    • Department of Biological SciencesWright State University
    • Department of Biological SciencesWright State University
  • Yongding Liu
    • Institute of Hydrobiologythe Chinese Academy of Sciences
  • Makoto M. Watanabe
    • National Institute for Environmental Studies

DOI: 10.1023/A:1004166029866

Cite this article as:
Li, R., Carmichael, W.W., Liu, Y. et al. Hydrobiologia (2000) 438: 99. doi:10.1023/A:1004166029866


The taxonomy of Aphanizomenon flos-aquae strain NH-5, a producer of cyanotoxins, was re-evaluated by comparison with six other Aphanizomenon strains using morphological characteristics and 16S rRNA gene sequences. Strain NH-5 was concluded to be improperly identified as Aph. flos-aquae based upon (1) lack of bundle formation in the trichomes, (2) location of akinetes next to heterocytes, (3) lower similarities (less than 97.5%) in the 16S rRNA gene sequences relative to Aph. flos-aquae strains, and (4) comparison within a phylogenetic tree constructed from 16S rRNA gene sequences. The Aphanizomenon strains investigated in this study are classified to four morphological groups as described by the classical taxonomy of Komárek & Kovácik (1989). This classification was supported from the phylogenetic results of 16S rRNA gene sequences. This study also discusses the generic boundaries between Aphanizomenon and Anabaena.

AphanizomenonCyanobacteria16S rRNAmorphologysequencestaxonomy

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© Kluwer Academic Publishers 2000