Introduction: Recent developments in cyanobacterial research with special reference to aquatic habitats, molecular ecology and phylogenetic taxonomy

Abstract

The global importance of cyanobacteria is well known from their worldwide distribution and abundance as well as their contribution to atmospheric oxygen. In spite of a long history of cyanobacterial research in microbiology and botany, only a small portion of their high diversity has been recovered and only recently been addressed by molecular and phylogenetic methods. Controversies in traditional and modern approaches to cyanobacterial taxonomy still persist, which has stimulated their discussion within the 20th IAC Symposium. In this special section, we present a set of nine contributions, selecting the most interesting outcomes of the meeting. The molecular approaches applied deal on one hand, with classical single and multilocus phylogenetic taxonomy methods, on the other hand with high-throughput next generation sequencing methods to rapidly identify diversity of cyanobacteria in environmental samples without the possibility to investigate their taxonomic status in depth. The studied ecosystems include a variety of freshwater, brackish and marine, planktonic and benthic habitats from which cyanobacteria were sampled. Study regions comprise temperate, arctic, alpine and tropical environments from four continents. We discuss the salient points of the contributions from this volume and formulate four main issues from which conclusions are drawn in order to contribute to future progress in cyanobacterial research.

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

“…The phenotypic flexibility of some standard diagnostic features in the taxonomy of cyanoprokaryotes-including the shape and structure of colonies, presence/absence of gas vesicles, akinetes, or heterocytes [5][6][7][8]-has promoted the parallel use of both morphological and molecular phylogenetic data in a common polyphasic approach [9][10][11]. This approach includes different molecular techniques and is increasingly employed for the analysis of environmental samples (e.g., [12][13][14][15][16][17][18][19]). However, the assignment of taxa to sequences is often a challenge in molecular-based classification methods applied to environmental samples [19,20].…”

“…This approach includes different molecular techniques and is increasingly employed for the analysis of environmental samples (e.g., [12][13][14][15][16][17][18][19]). However, the assignment of taxa to sequences is often a challenge in molecular-based classification methods applied to environmental samples [19,20]. For early detection of potentially toxigenic cyanobacteria and cyanotoxins, rapid, reliable, and economically effective molecular approaches based on a PCR (polymerase chain reaction) targeting genes involved in the biosynthesis of cyanotoxins have been developed in the past 15 years [21].…”

Analysis of molecular diversity within single cyanobacterial colonies from environmental samples

“…In particular, in cyanobacteria, as in other prokaryotes, the 16S rDNA gene is currently the most commonly used marker for molecular and phylogenetic studies 51 , 52 . The information obtained from 16S rDNA gene phylogenetic reconstructions, together with morphological, ultrastructural, and ecological data, led Komárek et al 53 to propose the current accepted classification of cyanobacteria.…”

Morphological characterization and phylogenetic analysis of aeroterrestrial Vischeria/Eustigmatos strains with industrial potential

“…This approach exploits simultaneously conventional and molecular identification techniques [51] and is known mainly in the taxonomy of prokaryotes [52]. Among algae, the term was commonly used in the studies of cyanoprokaryotes/cyanobacteria [53][54][55][56][57][58] and rarer was applied in the taxonomy of eukaryotic algae [59][60][61][62].…”