Coccomyxa

Abstract: Peltigera (Peltigerineae, lichenized Ascomycota) is one of the most widespread lichen genera incorporating bi‐ and trimembered associations involving fungi, green algae (cf. Coccomyxa), and cyanobacteria (cf. Nostoc). A wide range of morphological and chemical (secondary compounds) variation at both the intra‐ and interspecific levels is present in this genus. Compared to many other genera of macrolichens, its taxonomy, including chemotaxonomy, still remains poorly understood. Existing infrageneric classifications of Peltigera are almost exclusively based on photobiont composition of the thallus. These classifications assumed that bi‐ and trimembered taxa were distinct monophyletic entities. The genus Peltigera has never been the focus of a comprehensive phylogenetic study. The most recent and widely accepted subdivision of the genus into seven groups is based mainly on morphological and chemical characters. Relationships among species of Peltigera are investigated here using chemical, morphological, and ...

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.

Abstract: The identity of the carbohydrate moving between the symbionts of a lichen depends on the genus of alga present. Twenty-seven lichen species, involving eight different genera of algae, have been examined. In lichens containing five genera of Chlorophyceae, carbohydrates move to the fungus as polyols (ribitol in Trebouxia, Myrmecia and Coccomyxa; erythritol in Trentepohlia; and sorbitol in Hyalococcus). In lichens containing three genera of Cyanophyceae (Nostoc, Calothrix and Scytonema) glucose was the carbohydrate moving, although there is a possibility that in the one lichen with Calothrix which was investigated, it may have been a glucan.