title: Evaluating the Species Boundaries of Green Microalgae (Coccomyxa, Trebouxiophyceae, Chlorophyta) Using Integrative Taxonomy and DNA Barcoding with Further Implications for the Species Identification in Environmental Samples.
abstract: Integrative taxonomy is an approach for defining species and genera by taking phylogenetic, morphological, physiological, and ecological data into account. This approach is appropriate for microalgae, where morphological convergence and high levels of morphological plasticity complicate the application of the traditional classification. Although DNA barcode markers are well-established for animals, fungi, and higher plants, there is an ongoing discussion about suitable markers for microalgae and protists because these organisms are genetically more diverse compared to the former groups. To solve these problems, we assess the usage of a polyphasic approach combining phenotypic and genetic parameters for species and generic characterization. The application of barcode markers for database queries further allows conclusions about the 'coverage' of culture-based approaches in biodiversity studies and integrates additional aspects into modern taxonomic concepts. Although the culture-dependent approach revealed three new lineages, which are described as new species in this paper, the culture-independent analyses discovered additional putative new species. We evaluated three barcode markers (V4, V9 and ITS-2 regions, nuclear ribosomal operon) and studied the morphological and physiological plasticity of Coccomyxa, which became a model organism because its whole genome sequence has been published. In addition, several biotechnological patents have been registered for Coccomyxa. Coccomyxa representatives are distributed worldwide, are free-living or in symbioses, and colonize terrestrial and aquatic habitats. We investigated more than 40 strains and reviewed the biodiversity and biogeographical distribution of Coccomyxa species using DNA barcoding. The genus Coccomyxa formed a monophyletic group within the Trebouxiophyceae separated into seven independent phylogenetic lineages representing species. Summarizing, the combination of different characteristics in an integrative approach helps to evaluate environmental data and clearly identifies microalgae at generic and species levels.
authors.affiliation: M. G. Kholodny Institute of Botany, National Academy Science of Ukraine, Kyiv 01601, Ukraine.
authors.forename: Tatyana
authors.initials: T
authors.lastname: Darienko
authors.affiliation: University of Rostock, Institute of Biological Sciences, Applied Ecology and Phycology, Albert-Einstein-Strasse 3, D-18059 Rostock, Germany.
authors.forename: Lydia
authors.initials: L
authors.lastname: Gustavs
authors.affiliation: Leibniz Institute for Baltic Sea Research Warnemünde, Physical Oceanography, D-18119 Rostock, Germany.
authors.forename: Anja
authors.initials: A
authors.lastname: Eggert
authors.affiliation: University of Rostock, Institute of Biological Sciences, Applied Ecology and Phycology, Albert-Einstein-Strasse 3, D-18059 Rostock, Germany.
authors.forename: Wiebke
authors.initials: W
authors.lastname: Wolf
authors.affiliation: University of Rostock, Institute of Biological Sciences, Applied Ecology and Phycology, Albert-Einstein-Strasse 3, D-18059 Rostock, Germany; University of Vienna, Department of Limnology and Biooceanography, A-1090 Vienna, Austria.
authors.forename: Thomas
authors.initials: T
authors.lastname: Pröschold
mesh_terms: D044822:Biodiversity; D000460:Chlorophyta / Q000145:classification / Q000235:genetics* / Q000254:growth & development; D002965:Classification / Q000379:methods; D058893:DNA Barcoding, Taxonomic; D005819:Genetic Markers; D014644:Genetic Variation; D058086:Microalgae / Q000145:classification / Q000235:genetics* / Q000254:growth & development; D010802:Phylogeny; D013045:Species Specificity
chemical_list: D005819:Genetic Markers