Fig 1 - uploaded by Petr Dvorak
Content may be subject to copyright.
Illustration of morphological diversity in cyanobacteria. Groups (orders) follow Rippka et al. (1979). I. Chroococcales: a Chroococcus subnudus, b Ch. limneticus, c Cyanothece aeruginosa, d Snowella litoralis, e Microcystis aeruginosa. II. Pleurocapsales: f Pleurocapsa minor. III. Oscillatoriales: g Planktothrix agardhii, h Limnothrix redekei, i Arthrospira jenneri, j Johanseninema constricum, k Phormidium sp., l, m Oscillatoria sp., n Schizothrix sp., o Tolypothrix sp., p Katagnymene accurata., IV. Nostocales: q Dolichospermum planctonicum, r Dolichospermum sp., s Nostoc sp., t Nodularia moravica. V. Stigonematales: u, v Stigonema sp. Scale bar a–u = 10 lm, v = 20 lm. (Color figure online)
Source publication
The cyanobacteria are the most important prokaryotic primary producers on Earth, inhabiting a great diversity of aquatic and terrestrial environments exposed to light. However, the evolutionary forces leading to their divergence and speciation remain largely enigmatic compared to macroorganisms due to their prokaryotic nature, including vast popula...
Citations
... Some of these polyphyletic lineages have already been transferred into new genera (Dvořák, Hindák, et al., 2014;Komárek et al., 2020). This phenomenon is widely spread across most of the cyanobacterial lineages, and it has led to the boom of more than a hundred new genera within the last decade (Dvořák et al., 2015(Dvořák et al., , 2021Komárek et al., 2014). Second, the new monophyletic genera that have been defined based on the 16S rRNA gene phylogeny are often composed of several cryptic species, that is, no morphological features distinguish them. ...
Cyanobacterial taxonomy is entering the genomic era, but only a few taxo-
nomic studies have employed population genomics, which provides a frame-
work and a multitude of tools to understand species boundaries. Phylogenomic
and population genomic analyses previously suggested that several cryptic
lineages emerged within the genus Laspinema. Here, we apply population
genomics to define boundaries between these lineages and propose two new
cryptic species, Laspinema olomoucense and L. palackyanum. Moreover,
we sampled soil and puddles across Central Europe and sequenced the
16S rRNA gene and 16S-23S ITS region of the isolated Laspinema strains.
Together with database mining of 16S rRNA gene sequences, we determined
that the genus Laspinema has a cosmopolitan distribution and inhabits a
wide variety of habitats, including freshwater,
... Accurate identification of cyanobacteria is important to optimize biodiversity management and strategies for agricultural, ecological, industrial and other important purposes. However, identification of cyanobacterial genera and species based on morphology alone is difficult due to overlapping morphological characteristics among species (Dvořák et al. 2015, Komárek 2016, Brown et al. 2021. Previous studies suggested that the modern taxonomic identification method known as the polyphasic approach should be based not only on morphological features but also prepared as described by Tawong et al. (2022b) and used for solid and liquid cultures. ...
In this study, novel Calothrix-like strains NUACC09 and NUACC10 were isolated from the surfaces of rocks in Phayao Lake, Thailand. Morphological, molecular and ecological comparisons were investigated to characterize the taxonomic status of these novel strains. Under the light microscope, morphological studies indicated that these two strains were morphologically similar to Calothrix but could be differentiated by production of a non-hyaline hair at the terminal end, a low degree of tapering, twisted or loop-forming filaments, a knotted growth form, intertwined trichomes and presenting more than one trichome within the single sheath. In the 16S rRNA and rbcLX gene phylogenetic tree analyses, our strains formed a monophyletic clade with former freshwater/terrestrial Calothrix-like taxa separating distantly from other Calothrix-like genera. Furthermore, low 16S rRNA gene sequence similarity (<94.9%) to the closely related genera and species delimitation analyses (PTP/bPTP, GMYC, ABGD and ASAP methods) indicated that this clade should be considered as a different cyanobacterial lineage. The phylogenetic tree and secondary structures (D1–D1′, V2, Box-B and V3 helix) based on 16S–23S rRNA ITS regions suggested that multiple species might be contained in this clade. Therefore, here, Phayaothrix was proposed as a novel cyanobacterial genus with Phayaothrix lacustris sp. nov. as the type species following the International Code of Nomenclature for algae, fungi and plants.
... Additionally, phylogenetic reconstructions demonstrated that a large number of genera previously regarded to have consistent morphological traits were polyphyletic [6,7]. These polyphyletic genera, sometimes referred to as cryptogenera, may have resulted from multiple lineages of cyanobacteria undergoing frequent evolutionary convergence [8][9][10]. ...
During the study of diversity in filamentous cyanobacteria in China, two strains (WZU0719 and WZU0723) with the form of thin filaments were isolated from the surface of Qiandao Lake, a large freshwater lake in Zhejiang Province, China. A comprehensive analysis was conducted, incorporating morphological, ecological, and molecular data. The morphological examination provided an initial identification as a Leptolyngbya-like cyanobacterium. Genetic characterization was also performed by amplifying the 16S rRNA gene and the 16S-23S rRNA internal transcribed spacer (ITS) region. The phylogenetic grouping based on the 16S rRNA gene demonstrates that the examined strain is unequivocally assigned to the Pegethrix genus. However, it possesses distinct phylogenetic divergence from the six described Pegethrix species. Additionally, discrepancies in habitat further differentiate it from other members of this genus. Employing the polyphasic approach, we present a comprehensive account of the newly discovered taxa: Pegethrix qiandaoensis sp. nov. The novel taxonomic finding in this research significantly contributes to enhancing the comprehension of Pegethrix diversity across various habitats.
... The 16S rRNA marker simply is not sensitive enough to distinguish between closely related species within the speciation continuum. 21,40,41 The commonly used genome-similarity ANI value also proved ineffective for the Microcoleus species. 6 The ANI value, like other similarity-based methods, does not take into account the dynamic processes of speciation, and the set boundaries between species are often arbitrary. ...
The filamentous cyanobacterium Microcoleus is among the most important global primary producers, especially in hot and cold desert ecosystems. This taxon represents a continuum consisting of a minimum of 12 distinct species with varying levels of gene flow and divergence. The notion of a species continuum is poorly understood in most lineages but is especially challenging in cyanobacteria. Here we show that genomic diversification of the Microcoleus continuum is reflected by morphological adaptation. We compiled a dataset of morphological data from 180 cultured strains and 300 whole genome sequences, including eight herbarium specimens and the type specimen of Microcoleus. We employed a combination of phylogenomic, population genomic, and population-level morphological data analyses to delimit species boundaries. Finally, we suggest that the shape of the filament apices may have an adaptive function to environmental conditions in the soil.
... Some of these polyphyletic lineages have already been transferred into the new genera (Dvořák et al. 2014b, Komarek et al. 2020). This phenomenon is widely spread across most of the cyanobacterial lineages and it has led to the boom of more than a hundred of new genera within the last decade (Komárek et al. 2014, Dvořák et al. 2015. Second, the new monophyletic genera defined based on the 16S rRNA phylogeny are often composed of several cryptic species, i.e., no morphological features distinguishing them. ...
Cyanobacterial taxonomy is entering the genomic era, but only a few taxonomic studies have employed population genomics, which provides a framework and a multitude of tools to understand species boundaries. Phylogenomic and population genomic analyses previously suggested that several cryptic lineages emerged within the genus Laspinema. Here, we apply population genomics to define boundaries between these lineages and propose new cryptic species, Laspinema olomoucense and Laspinema palackyanum. Moreover, we sampled soil and puddles across Central Europe and sequenced the 16S rRNA and 16S-23S ITS of the isolated Laspinema strains. Together with database mining of 16S rRNA sequences, we found that the genus Laspinema has a cosmopolitan distribution and inhabits a wide variety of habitats, including freshwater, saline water, mangroves, soil crusts, soils, puddles, and the human body.
... Measurements were carried out with Sigma-Scan Image analytical software (Sausalito, CA, USA) and Motic Images Plus (Motic Group, Hong Kong, China), using a calibrated ocular micrometer and in-scale projections and photomicrographs. Phenotype determination was performed using the available monographs and identification manuals (see [94]) as well as more recent publications, e.g., [95][96][97][98][99][100]. Some taxonomic revisions with designation changes were introduced following our phylogenetic reconstructions. ...
Located in the heart of the South Pacific Ocean, the French Polynesian islands represent a remarkable setting for biological colonization and diversification, because of their isolation. Our knowledge of this region’s biodiversity is nevertheless still incomplete for many groups of organisms. In the late 1990s and 2000s, a series of publications provided the first checklists of French Polynesian marine algae, including the Chlorophyta, Rhodophyta, Ochrophyta, and Cyanobacteria, established mostly on traditional morphology-based taxonomy. We initiated a project to systematically DNA barcode the marine flora of French Polynesia. Based on a large collection of ~2452 specimens, made between 2014 and 2023, across the five French Polynesian archipelagos, we re-assessed the marine floral species diversity (Alismatales, Cyanobacteria, Rhodophyta, Ochrophyta, Chlorophyta) using DNA barcoding in concert with morphology-based classification. We provide here a major revision of French Polynesian marine flora, with an updated listing of 702 species including 119 Chlorophyta, 169 Cyanobacteria, 92 Ochrophyta, 320 Rhodophyta, and 2 seagrass species—nearly a two-fold increase from previous estimates. This study significantly improves our knowledge of French Polynesian marine diversity and provides a valuable DNA barcode reference library for identification purposes and future taxonomic and conservation studies. A significant part of the diversity uncovered from French Polynesia corresponds to unidentified lineages, which will require careful future taxonomic investigation.
... Morphological diversity of cyanobacteria(Dvořák et al., 2015) ...
... These prokaryote organisms are termed cyanophytes, cyanoprokaryotes, and blue-green algae. Cyanobacteria exist in environments in different morphologies such as unicellular, colonial, ranched filamentous, and unbranched filamentous with trichomes, as shown inFigure 1(Dvořák et al., 2015). These microorganisms occur in diverse environments, from aquatic (freshwater and marine) to terrestrial, and they can inhabit in different extreme environments such as high salinity, geothermal springs, and deserts(Nandagopal et al., 2021). ...
Cyanobacteria a group of photosynthetic
microorganisms, exist in almost all ecosystems in the
world. Regarding health and disease prevention,
cyanobacteria have been cited as a promising natural
source of diverse secondary metabolites that exhibit
significant bioactivities with potential pharmacological
uses. Presently, great attention has been concentrated on
the anticancer role of aquatic cyanobacteria that
comprise an important source of bioactive compounds.
Cyanobacteria-derived natural compounds and their
synthetic analogs exhibited attractive results and showed
remarkable activity by reaching phase II and III clinical
trials successfully. Therefore, natural products from
cyanobacteria might represent promising sources for
novel anticancer therapy. Besides, microbial infections
and infectious diseases from antimicrobial resistance
(AMR) pose a direct threat to health and well-being
because of the increase in antimicrobial resistance and
the evolution of novel pathogenic strains. The search for
novel antibiotics become increasingly urgent. Extensive
efforts have been invested to find antimicrobial
compounds from cyanobacteria to limit the misuse of commercial antibiotics. The development of natural
anticancer and antimicrobial compounds from fresh
water and marine cyanobacterial metabolites is a
valuable trial. This review article summarizes the
reported anticancer, antiviral, antifungal, and
antibacterial properties of cyanobacteria and their
mechanisms of action.
... These species concepts are an everlasting topic of discussion and confusion among many biologists. Alternately, some biologists do not seek species concepts, and they identify species subjectively; they do not specify any species concept (summarized in [79]), which floods the taxonomy of cyanobacteria with a fuzziness together with other reasons e.g., cryptic diversity and not curated names in databases such as GenBank (see Section 5) [20,80,81]. Thus, we will focus on species concepts that are the most frequently applied to cyanobacteria or which can be applied via population genomics. ...
... Thus, most species descriptions before the advent of the sequencing were based on the phenotype (cell dimensions, sheath characteristics, etc.). However, scant morphological diversity may actually conceal enormous genetic diversity, leading to cryptic diversity (more details in Section 5) [34,80,82,83]. ...
... Since there is no sexual reproduction in cyanobacteria, the biological species concept (BSC) was long omitted in the species debate [80]. Homologous recombination (HR), though, may produce similar patterns of evolution as seen with meiotic recombination during sexual reproduction of eukaryotes. ...
The emergence of cyanobacterial species (speciation) is driven by mutation, selection, gene flow, and geographical and ecological isolation. Population genomics explores the process of speciation and in turn provides information for our understanding of evolution, diversity, and systematics. However, very little is known about speciation in cyanobacteria, and no framework exists to apply population genomics to taxonomy. Here we review the forces driving the speciation of cyanobacteria and the application of population genomics to taxonomy. We start by discussing species divergence, selection, gene flow, and the phases of speciation. Then we focus on the most frequently used species concepts and their application using population genomics and methods of species delimitation using examples of Prochlorococcus, Microcystis, and Laspinema. Finally, we present guidelines for the methods and techniques of population genomics and their application in the taxonomy of cyanobacteria. Population genomics provides the tools and approaches to bridge species' biology, evolution, and delimitation. Ultimately, this brings taxonomic decisions as close as possible to natural processes.
... However, we employed molecular markers which are relatively conservative and reflect only a small portion of the genome. Still, this is in sharp contrast to the frequently observed cryptic species unrecognizable based on their morphological characters but possessing large genomic differences (Dvořák et al. 2015;Stanojković et al. 2022). In any case, the divergence in the bacterial genome is uneven during the speciation and many phenotypic changes can be coded in the accessory genome (reviewed in Shapiro and Polz 2015). ...
Our observations of natural mats composed of Kamptonema animale (C.Agardh ex Gomont) Strunecký, Komárek et J. Šmarda brings new knowledge about its morphological characteristics. The black fertile parts of the geoglossoid fungus Trichoglossum octopartitum (Geoglossaceae), collected in grassland in Rojkov, Central Slovakia, were overgrown with motile violet to purple filaments that were well visible mainly in subcultures due to color predominance of the fungi. The original description of the genus Kamptonema, a filamentous cyanobacterium of the family Microcoleaceae, order Oscillatoriales, was most recently supplemented based on the cytomorphological and molecular markers of clonal populations obtained from cultures, largely from Culture Collection of Autotrophic Organisms (CCALA). We propose an extension of the original diagnosis based on the morphological characteristics of the studied natural populations, as molecular studies (analyses of 16S rRNA and 16S-23S ITS region) showed an agreement with the species K. animale, the type species of the genus Kamptonema Strunecký, Komárek et J. Šmarda.
... In modern cyanobacterial taxonomy, the genus should be a monophyletic cluster, and the species should be well characterized using a polyphasic approach. The polyphasic approach has become the gold standard in cyanobacterial taxonomy by providing all available informative data on morphology, cell ultrastructure, ecology, physiology, and biochemical traits [30][31][32][33]. ...
The Chroococcales is one of the least studied cyanobacterial orders comprising the non-baeocyte-producing coccoids cyanobacteria with stacked and fasciculated thylakoids. During a survey of aquatic biodiversity in Caohai Lake in Guizhou Province, China, a coccoid-like cyanobacterium was isolated. It was characterized using a polyphasic approach, based on morphology, electron microscopy, and molecular phylogenetic analyses. This species’ colonies exhibited morphological similarity to those of Microcystis species but differed in their larger colony sizes and widely oval cells. The 16S rRNA gene sequence of this species had the maximum homology, corresponding to 93.10%, to that of the genus Microcystis. The results of 16S rRNA gene threshold value and 16S rRNA phylogenetic analyses confirmed that the studied species belongs to the family Microcystaceae but is phylogenetically distinct from the other species of Microcystaceae. Furthermore, The D1–D1′, Box–B helix, and V3 helix of the 16S–23S ITS region were also different from those previously described in Microcystaceae taxa. Combining the morphological, ecological, and molecular features of the coccoid-like cyanobacterium, we here propose the establishment of the Cyanodorina gen. nov. and the Cyanodorina ovale sp. nov.
