Generic and species concepts in<i>Microglena</i>(previously the<i>Chlamydomonas monadina</i>group) revised using an integrative approach

Sutherland

European Journal of Phycology

et al. 2013

The status of the green algal genera Haematococcus and Stephanosphaera has been a source of debate among algal systematists. A phylogenetic alliance between Haematococcus (sensu lato) and the colonial Stephanosphaera was affirmed by earlier molecular phylogenetic investigations. Although the data suggested that the genus Haematococcus may not be a monophyletic group, taxon sampling limited the scope of any potential taxonomic revision. Results from new molecular phylogenetic analyses of data from the 18S and 26S rRNA genes support the establishment of a separate genus, Balticola, as originally proposed by Droop in 1956. Haematococcus remains as a valid genus, with H. pluvialis as its only member. The monotypic status of H. pluvialis is supported both by molecular phylogenetic analyses of the ribosomal RNA genes and assessments of molecular evolution in the ITS2 sequences of H. pluvialis strains. The near-complete absence of compensatory base changes in a sequencestructure analysis of the highly variable ITS2 gene from more than 40 geographically diverse isolates of H. pluvialis corroborates the unity of the species inferred from molecular phylogenetic analyses of 18S and 26S rRNA gene sequence data.

Section: Introductionmentioning

confidence: 97%

Section: Convergent or Ancestral Traitsmentioning

confidence: 99%

See 1 more Smart Citation

The blood alga: phylogeny ofHaematococcus(Chlorophyceae) inferred from ribosomal RNA gene sequence data

Sutherland

European Journal of Phycology

et al. 2013

“…The chlorophyte Chlamydomonas monoica (59), one of an interfertile group that includes Chlamydomonas noctigama and Chlamydomonas geitleri, is a member of the Moewusii clade that also includes Chlamydomonas eugametos; this lineage is only distantly related to the Reinhardtinia clade that includes the wellstudied species Chlamydomonas reinhardtii (60)(61)(62). The eisosomes of C. eugametos have been imaged previously (37,38).…”

Section: Resultsmentioning

confidence: 99%

“…9) (37,38). In contrast, the eisosomes of two members of the branching Chloromonas clade (61,88), Chlamydomonas nivalis/augusta and Chlamydomonas yellowstoniensis, display a standard, nonreversed orientation (3). (ii) Among the trebouxiophytes, Auxenochlorella protothecoides, in the Chlorella lineage clade (54), has a broad-banded eisosomal concave face (Fig.…”

Section: Discussionmentioning

confidence: 99%

Eisosome Ultrastructure and Evolution in Fungi, Microalgae, and Lichens

et al. 2015

Eisosomes are among the few remaining eukaryotic cellular differentations that lack a defined function(s). These trough-shaped invaginations of the plasma membrane have largely been studied in Saccharomyces cerevisiae, in which their associated proteins, including two BAR domain proteins, have been identified, and homologues have been found throughout the fungal radiation. Using quick-freeze deep-etch electron microscopy to generate high-resolution replicas of membrane fracture faces without the use of chemical fixation, we report that eisosomes are also present in a subset of red and green microalgae as well as in the cysts of the ciliate Euplotes. Eisosome assembly is closely correlated with both the presence and the nature of cell walls. Microalgal eisosomes vary extensively in topology and internal organization. Unlike fungi, their convex fracture faces can carry lineagespecific arrays of intramembranous particles, and their concave fracture faces usually display fine striations, also seen in fungi, that are pitched at lineage-specific angles and, in some cases, adopt a broad-banded patterning. The conserved genes that encode fungal eisosome-associated proteins are not found in sequenced algal genomes, but we identified genes encoding two algal lineage-specific families of predicted BAR domain proteins, called Green-BAR and Red-BAR, that are candidate eisosome organizers. We propose a model for eisosome formation wherein (i) positively charged recognition patches first establish contact with target membrane regions and (ii) a (partial) unwinding of the coiled-coil conformation of the BAR domains then allows interactions between the hydrophobic faces of their amphipathic helices and the lipid phase of the inner membrane leaflet, generating the striated patterns.

Contemporary integrative taxonomy for sexually deprived protists: A case study of Trachelomonas (Euglenaceae) from western Ukraine

Čalasan

Kretschmann

Gottschling

2020

TAXON

As many other protist groups, euglenophytes are prone to false identification based solely on morphology because of a limited amount of morphological features and cryptic speciation. One of the supposedly completely asexual groups within the freshwater phototrophic representatives of euglenophytes is Trachelomonas, capable of forming an inorganic shell around its cell (i.e., the lorica). The International Code of Nomenclature for algae, fungi, and plants regulates the taxonomy not only of flowering plants, but explicitly also of phototrophic protists, and provides powerful tools to resolve various taxonomic challenges. To exemplify some of the problems and potential solutions, a number of Trachelomonas strains were collected from the muddy, lake-rich region of Dobrostany and cultivated under stable laboratory conditions. Being a type locality of 58 unclarified Trachelomonas names, this region in western Ukraine is of great taxonomic importance. Based on light and electron microscopy, and on RAxML and MrBayes phylogenetics using multiple loci and a representative taxon sample, a detailed description of investigated strains and their systematic placement is provided. Morphologically, the strains differed slightly but consistently in minute characters such as size, lorica shape and ornamentation. The presently most comprehensive molecular tree of the Euglenaceae indicated to the existence of at least five different species present in the newly investigated samples, although they were collected from localities in very close vicinity to each other and at the same date. Based on morphological comparisons with type illustrations of species validly described 100 or more years ago, biological material was used to epitypify three names of Trachelomonas, eternally linking morphology with reliable genetic information. This taxonomic application is one of the powerful methods to clarify ambiguous scientific names, which has particular importance in characterpoor protists such as the euglenophytes.