Phylogenetic relationships of some filamentous cyanoprokaryotic species

Abstract

Te polyphasic approach is the most progressive system that has been suggested for distinguishing and phylogenetically classifying Cyanoprokaryota (Cyanobacteria/Cyanophyta). Several oscillatorialean genera (Lyngbya, Phormidium, Plectonema, and Leptolyngbya) have problematic phylo genetic position and taxonomic state because of their heterogeneity and polyphyletic nature. To accurately resolve the phylogenetic relationship of some flamentous species (Nodosilinea bijugata, Phormidium molle, Phormidium papyraceum), we have performed phylogenetic analyses based on 16S rRNA gene and the phycocyanin operon (PC-IGS) by using maximum-likelihood (ML) tree inference methods. Tese analyses were combined with morphological re-evaluation. Our phylogenetic analyses support the taxonomic separation of genus Nodosilinea from the polyphyletic genus Leptolyngbya. Investigated Nodosilinea strains always formed a coherent genetic cluster supported with a high bootstrap value. Te molecular phylogeny confrmed also the monophyly of the Wilmottia group. In addition, data reveal that although P. papyraceum is morphologically similar to Wilmottia murrayi, this species is genetically distinct. Strains from the newly formed genus Phormidesmis and some Phormidium priestleyi strains were clustered in a separate clade diferent from the typical Phormidium species, but without strong bootstrap support. © the authors, publisher and licensee libertas academica limited. this is an open-access article distributed under the terms of the creative commons cc-By-nc 3.0 license. © the authors, publisher and licensee Libertas Academica Limited.