, Volume 438, Issue 1, pp 99-105

First online:

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

  • Renhui LiAffiliated withDepartment of Biological Sciences, Wright State University
  • , Wayne W. CarmichaelAffiliated withDepartment of Biological Sciences, Wright State University Email author 
  • , Yongding LiuAffiliated withInstitute of Hydrobiology, the Chinese Academy of Sciences
  • , Makoto M. WatanabeAffiliated withNational Institute for Environmental Studies

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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.

Aphanizomenon Cyanobacteria 16S rRNA morphology sequences taxonomy