Abstract
Most marine coccoid and sarcinoid green algal species have traditionally been placed within genera dominated by species from freshwater or soil habitats. For example, the genera Chlorocystis and Halochlorococcum contain exclusively marine species; however, their familial and ordinal affinities are unclear. They are characterized by a vegetative cell with lobated or reticulated chloroplast, formation of quadriflagellated zoospores and living epi- or endophytically within benthic macroalgae. They were integrated into the family Chlorochytriaceae which embraces all coccoid green algae with epi- or endophytic life phases. Later, they were excluded from the family of Chlorococcales based on studies of their life histories in culture, and transferred to their newly described order, Chlorocystidales of the Ulvophyceae. Both genera form a “Codiolum”-stage that serves as the unicellular sporophyte in their life cycles. Phylogenetic analyses of SSU and ITS rDNA sequences confirmed that these coccoid taxa belong to the Chlorocystidales, together with the sarcinoid genus Desmochloris. The biflagellated coccoid strains were members of the genus Sykidion, which represented its own order, Sykidiales, among the Ulvophyceae. Considering these results and the usage of the ITS-2/CBC approach revealed three species of Desmochloris, six of Chlorocystis, and three of Sykidion. Three new species and several new combinations were proposed.
Highlights
Successful invasion of the land by marine organisms, or of the sea by freshwater organisms, is generally considered as a relatively rare event in evolution
The SSU and ITS rDNA were sequenced after DNA extraction, and PCR protocols were published in Darienko et al [6]
The initial goal of this study was to present a comprehensive analysis of the phylogeny and taxonomy of coccoid and sarcinoid green algae found in marine habitats
Summary
Successful invasion of the land by marine organisms, or of the sea by freshwater organisms, is generally considered as a relatively rare event in evolution. Among the coccoid green algae, once placed together in the order Chlorococcales, there are a number of marine forms amongst the overwhelming freshwater majority. Most marine coccoid green algal species have traditionally been placed within genera dominated by species from freshwater or soil habitats [3]. The type species of Chlorella (C. vulgaris Beijerinck) is positioned within the Trebouxiophyceae, but the marine species described as Halochlorella rubescens Dangeard (authentic strain SAG 5.95) is a member of the Chlorophyceae [4] and was transferred to Scenedesmus (S. rubescens) by Kessler et al [5].
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
