1a) confirms what others have found in the heterocytous cyanobacterial taxa: typical cut-offs for taxon recognition (<95% for genera, <97.5% for species; Stackebrandt and Goebel 1994, Ludwig et al. 1998) are much too conservative for recognizing taxonomic diversity in this clade (Lyra et al. 2001, Flechtner et al. 2002, Rajaniemi et al. 2005, Řeháková et al. 2007, Kaštovský and Johansen 2008, Lukešová et al. 2009, Vaccarino and Johansen 2012).
For example, Aulosira bohemensis is as high as 97.8% similar LBH589 price to species in Cylindrospermum sensu stricto, well above the cut-off for different species within a single genus. We conclude that 16S rRNA gene similarity fails as a criterion for recognizing taxonomic diversity in the Nostocaceae, at least at above mentioned levels suggested for bacteria. This study is the first to examine Cylindrospermum using a polyphasic approach. It is evident that the combination of morphological and molecular data sets permits a clearer recognition of evolutionary diversity within the cyanobacteria. The high similarity of the ribosomal genes suggests recent rapid divergence within the genus, as morphological diversity exceeds variation observable in the housekeeping genes. GSI-IX Certainly, further study in Cylindrospermum and related genera in the Nostocaceae
is necessary to reveal the diversity within this important family. The research was supported by grants MŠMT/AMVIS LH12100, and a long-term research development project no. RVO67985939 (Academy of click here Sciences of the Czech Republic). Collection, isolation and sequencing of Cylindrospermum HA04236-MV2, as well as other cyanobacteria in our phylogenetic analysis from Hawaii were completed with support from National Science Foundation grant number DEB–0842702. Any opinions, findings, conclusions, or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation. Access to the MetaCentrum
computing facility provided under the program National Grid Infrastructure MetaCentrum (LM2010005) is greatly appreciated. Table S1. Summary of Cylindrospermum strains newly isolated in course of this study. Strains CCALA 988-1000 are kept in parallel at the Institute of Soil Biology of the Academy of Science of the Czech Republic in České Budějovice, Czech Republic under strain codes including information on year of isolation. Herbarium and sequence accession numbers are also provided. Table S2. Habitat type and locality of origin for the Cylindrospermum strains included in the study (where known). Table S3. Annotated alignment of 16S-23S ITS regions used in phylogenetic analyses of Cylindrospermum species in this study. Operons with both tRNA genes are aligned separately from operons lacking tRNA genes. Table S4. Similarity (P-distance) among representative strains of Cylindrospermum and diverse Nostocaceae in this study. Table S5.