Difference without distinction? Gaps in cyanobacterial systematics; when more is just too much

Dvořák, Petr; Jahodářová, Eva; Casamatta, Dale A.; Hašler, Petr; Poulíčková, Aloisie

doi:10.5507/fot.2017.023

Cited by 18 publications

(16 citation statements)

References 43 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…On the one hand, the low number of affiliations was due to the recent general low availability of genomic sequences from cyanobacteria when compared to other prokaryotes [47]. In the same time, five of the NCBI sequences used in the obtained phylogenetic tree (Figure 9) were based on metagenomic data (genetic material recovered directly from uncultured organisms from environmental samples- [48]). Despite the increased application of these data in modern studies based on the common difficulties, or even impossibility, to culture some cyanobacteria [47], their use in identification work is problematic because of the lack of morphological descriptions for most of the sequenced uncultured strains.…”

Section: Discussionmentioning

confidence: 99%

Morphological and Molecular Identification of Microcystin-Producing Cyanobacteria in Nine Shallow Bulgarian Water Bodies

Radkova

Stefanova

Uzunov

et al. 2020

Toxins

View full text Add to dashboard Cite

The paper presents results from the first application of polyphasic approach in studies of field samples from Bulgaria. This approach, which combined the conventional light microscopy (LM) and molecular-genetic methods (based on PCR amplified fragments of microcystin synthetase gene mcyE), revealed that almost all microcystin-producers in the studied eutrophic waterbodies belong to the genus Microcystis. During the molecular identification of toxin-producing strains by use of HEPF × HEPR pair of primers, we obtained 57 sequences, 56 of which formed 28 strains of Microcystis, spread in six clusters of the phylogenetic tree. By LM, seven Microcystis morphospecies were identified (M. aeruginosa, M. botrys, M. flos-aquae, M. natans, M. novacekii, M. smithii, and M. wesenbergii). They showed significant morphological variability and contributed from <1% to 98% to the total biomass. All data support the earlier opinions that taxonomic revision of Microcystis is needed, proved the presence of toxigenic strains in M. aeruginosa and M. wesenbergii, and suppose their existence in M. natans. Our results demonstrated also that genetic sequencing, and the use of HEPF × HEPR pair in particular, can efficiently serve in water quality monitoring for identifying the potential risk from microcystins, even in cases of low amounts of Microcystis in the water.

show abstract

Section: Discussionmentioning

confidence: 99%

Morphological and Molecular Identification of Microcystin-Producing Cyanobacteria in Nine Shallow Bulgarian Water Bodies

Radkova

Stefanova

Uzunov

et al. 2020

Toxins

View full text Add to dashboard Cite

show abstract

“…In this study, we used tree-based methods (GMYC, bPTP) on the 16S rRNA dataset [96][97][98][99], and found that the results of the similarity method were almost in accord with those of tree-based analyses. Dvořa ´k et al [100] only used the PTP method, and proved that it could adequately delimit the cyanobacterial species. In the current study, the GMYC approach was more adept at recognizing species than the bPTP and ABGD approaches.…”

Section: Plos Onementioning

confidence: 99%

Thainema gen. nov. (Leptolyngbyaceae, Synechococcales): A new genus of simple trichal cyanobacteria isolated from a solar saltern environment in Thailand

et al. 2022

View full text Add to dashboard Cite

Simple trichal types constitute a group of cyanobacteria with an abundance of novel, often cryptic taxa. Here, we investigated material collected from wet surface-soil in a saline environment in Petchaburi Province, central Thailand. A morphological comparison of the isolated strain with similar known species, as well as its phylogenetic and species delimitation analyses based on the combined datasets of other related organisms, especially simple trichal cyanobacteria, revealed that the material of this study represented an independent taxon. Using a multifaceted method, we propose that this material represents a new genus, Thainema gen. nov., belonging to the family Leptolyngbyaceae, with the type species Thainema salinarum sp. nov. This novel taxon shares similar ecological habitats with strains previously placed in the same lineage.

show abstract

“…Identity in 16S rRNA should be more than 97% after Stackebrandt et al [71], or 95-96% of the whole-genome average nucleotide identity (ANI) [72]. Despite remarking the lack of a generally accepted quantitative threshold of genetic distance to describe a prokaryotic species, Willis and Woodhouse [16] showed that species delimitation in the cyanobacterial genera Raphidiopsis and Microcystis could be assessed with species boundaries occurring at ∼96% average nucleotide identity at the genomic level, together with a constrained homologous recombination capability.…”

Section: Do the Nomenclatural Entities That We Recognize As Differentmentioning

confidence: 99%

“…HGT events would be more frequent between species sharing a common particular environment and higher phylogenetic affinity, while the frequency of HGT events would be proportionally inverse with respect to the genomes genetic distance [16,60]. Therefore, the differential capability of DNA exchange through HGT may be the most important factor for species delimitation in cyanobacteria.…”

Section: Do the Nomenclatural Entities That We Recognize As Differentmentioning

confidence: 99%

“…Cyanobacteria show species delimitation issues similar to those of other prokaryotes. Species delimitation in prokaryotes is a more difficult task with respect to eukaryotes, since a common theoretical ground about the species concept such as the biological species concept in eukaryotes is of difficult application due to the lack of sexual reproduction processes [15,16]. As in other prokaryotes, cyanobacteria diversification occurred by adaptation to different environmental contexts thanks to their high phenotypic plasticity and niche adaptability [17].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Taxonomy and Species Delimitation in Cyanobacteria

Papini¹,

Falsini²,

Th³

2021

Preprint

View full text Add to dashboard Cite

Cyanobacteria are prokaryotes whose taxonomy follows the same rules of a code (the International Botanical Nomenclature Code, IBNC) built for eukaryotic photosynthetic organisms. Hence, names of cyanobacteria follow the same rules and are assigned to biological entities (species) that should correspond to eukaryotic species. The main difficulty in the current situation is that the species concept in eukaryotes is based theoretically mainly on the biological species concept, that is centered on genetic exchange through sexual reproduction or lack of them. However, as shown, this difference is important from a theoretical point of view, but also in eukaryotes, the boundaries between different species are very rarely checked experimentally by direct observation of sexual barriers and hybridization events. The main concept for species delimitation is hence that related to morphology and, more recently and always in relation to morphology, DNA sequences. The introduction of distances obtained from matrixes of aligned sequences in the framework of a barcoding project provides a quantitative interpretation of species delimitation in relation to genetic distance that can be used both in eukaryotes and prokaryotes. However, the introduction of quantitative criteria needs the definition of distance thresholds to identify the boundaries between different species and, for doing that, it is necessary to test the distance thresholds in models of traditionally defined and recognized species. An alternative approach may be the comparison of the molecular distance (quantitative approach) to data about the capability of strains/species to exchange genetic information. Unfortunately data about this last question is still scarce. The adoption of molecular criteria to check species boundaries based on morphological characters has proved particularly challenging in cyanobacteria: a known example is provided. In conclusion, the only possible approach appears to be the association of molecular data to the increase of available data about the cell structure and the variation thereof in different physiological situations, particularly at the ultrastructural level. A further necessity is the check of the typus for a large number of cyanobacteria species, often based on old basionyms. In many of these cases the typus is often a drawing and more rarely a herbarium specimen or a microscope slide. In many cases an epitypification or a neotypification appears to be necessary.

show abstract

Difference without distinction? Gaps in cyanobacterial systematics; when more is just too much

Cited by 18 publications

References 43 publications

Morphological and Molecular Identification of Microcystin-Producing Cyanobacteria in Nine Shallow Bulgarian Water Bodies

Morphological and Molecular Identification of Microcystin-Producing Cyanobacteria in Nine Shallow Bulgarian Water Bodies

Thainema gen. nov. (Leptolyngbyaceae, Synechococcales): A new genus of simple trichal cyanobacteria isolated from a solar saltern environment in Thailand

Taxonomy and Species Delimitation in Cyanobacteria

Contact Info

Product

Resources

About