BIOCHEMICAL TAXONOMY AND MOLECULAR PHYLOGENY OF THE GENUS CHLORELLA SENSU LATO (CHLOROPHYTA)

Abstract

A multimethod approach was used to characterize unicellular green algae that were traditionally assigned to the genus Chlorella Beijerinck and to resolve their phylogenetic relationships within the Chlorophyta. Biochemical, physiological, and ultrastructural characters, together with molecular data such as DNA base composition and DNA hybridization values, were compared with a molecular phylogeny based on complete 18S rRNA sequences. Our results show that Chlorella taxa are dispersed over two classes of chlorophytes, the Trebouxiophyceae and the Chlorophyceae. We propose that only four species should be kept in the genus Chlorella (Chlorophyta, Trebouxiophyceae)

Hidden levels of phylodiversity in Antarctic green algae: further evidence for the existence of glacial refugia

“…Numbers at nodes indicate statistical support: ML bootstrap proportions (more than 50) and BI posterior probabilities (more than 85). (Huss et al 1999) and are intermixed with temperate members of the clade. Likewise, the remaining trebouxiophycean Antarctic isolates are scattered among temperate freshwater green algae.…”

“…At least one strain from each ARDRA group (identical patterns) or morphological group (based on general characteristics such as size, shape and pigmentation) from each region was selected for sequencing. Sequencing of the 18S rRNA gene was performed using the primers P2 and P4 (see above) and the internal primers P5, P12, P14, P15 and P16 (respectively, 300., 1055,, 528., 960. and 536,;Huss et al 1999). Sequences were automatically assembled and visually checked in BIONUMERICS 4.6 and were deposited in GenBank under accession numbers FJ946881-FJ946908.…”

“…Several cases of incorrect taxon delineation and cryptic species diversity are being disclosed by application of molecular phylogeny. A well-known example is that of the coccoid alga Chlorella, which has been shown to be polyphyletic, with the different taxa placed in separate green algal classes (Huss et al 1999). DNA sequence data are therefore well placed to provide more insight into the green algal diversity on the Antarctic continent.…”

One step closer to eliminating the nomenclatural problems of minute coccoid green algae: Pseudochloris wilhelmii, gen. et sp. nov. (Trebouxiophyceae, Chlorophyta)

“…minutissima' SAG 1.80 (in the Sammlung von Algenkulturen der Universität Göttingen, Germany) and 'Nannochloris eucaryotum' UTEX 2502 (in the Culture Collection of Algae at the University of Texas at Austin, USA). These strains have nearly identical 18S rRNA gene sequences but are distantly related to the 'true' Chlorella or Nannochloris species (Huss et al, 1999;Krienitz et al, 1999;Henley et al, 2004). The closest known relative of this group was recently described as Chloroparva pannonica (Somogyi et al, 2011).…”

Morphology, ultrastructure and ecology of Muriella decolor (Chlorophyta) from subaerial habitats in Poland and the Antarctic

“…The samples from the caves and from the ice de− nuded areas demonstrated morphological similarities, likewise the habitats. In this study the scheme of Graham et al (2009) was followed, supported by a number of recent phylogenetic studies (Friedl and Zeltner 1994;Huss et al 1999).…”