About this Research Topic
Cyanobacteria are an immensely evolutionarily diverse group of photosynthesizing prokaryotes. They have significantly impacted the global ecosystem as primary producers and as the direct ancestor of the chloroplasts found in plants and algae. Moreover, with ongoing global environmental changes, cyanobacterial water blooms have become more frequent, which may cause health and environmental hazards.
The origin of cyanobacteria can be dated to 2.7 - 3.5 billion years ago. During this time, cyanobacteria have evolved to become incredibly diverse; they number at least 3000 species with additional species discovered virtually every week, but only a fraction of these have whole genome sequences available. Since cyanobacteria show extensive variability in a relatively high number of morphological features, their taxonomy was based on morphological characters. However, patterns of genome diversification do not often concur with patterns of morphological evolution. This may be exemplified by extreme polyphyly within morphologically uniform genera such as Synechococcus, Leptolygbya and Cylindrospermum. Thus, the convergence of morphological characters is very frequent and present among all major cyanobacterial lineages and, as a result, taxonomy of cyanobacteria has been experiencing significant changes. Horizontal gene transfer seem to be a significant factor in convergence, but we are still far from completely understanding the evolutionary forces responsible for evolutionary diversification within cyanobacteria. Moreover, genome variability (both structural and nucleotide) is extensive between species and populations and is not reflected in morphological or environmental variability. Nevertheless, genomic data from closely related species are scarce, with the exception of marine Prochlorococcus/Synechococcus cyanobacteria and freshwater Microcystis. Thus, it is difficult to draw any general patterns applicable to all cyanobacteria.
This Research Topic is focused on extending the coverage of cyanobacterial phylogeny with newly sequenced genomes from any kind of environment. We especially welcome submissions which will help to further elucidate genome-wide phylogenetic relationships among cyanobacteria and factors responsible for the convergence of morphotypes. This may include taxonomic studies erecting new taxa (studies based on single or few gene phylogenies will not be considered). Furthermore, studies concentrated on microevolutionary patterns in any cyanobacterial group are encouraged, particularly those aimed at discovering speciation patterns in cyanobacteria.
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