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Citation for Study 13318

About Citation title: "Morphology and phylogenetic position of the freshwater green microalgae Chlorochytrium (Chlorophyceae) and Scotinosphaera (Scotinosphaerales, ord. nov., Ulvophyceae)".
About Study name: "Morphology and phylogenetic position of the freshwater green microalgae Chlorochytrium (Chlorophyceae) and Scotinosphaera (Scotinosphaerales, ord. nov., Ulvophyceae)".
About This study is part of submission 13318 (Status: Published).

Citation

Skaloud P., Kalina T., Nemjova K., De clerck O., & Leliaert F. 2013. Morphology and phylogenetic position of the freshwater green microalgae Chlorochytrium (Chlorophyceae) and Scotinosphaera (Scotinosphaerales, ord. nov., Ulvophyceae). Journal of Phycology, 49(1): 115?129.

Authors

  • Skaloud P.
  • Kalina T.
  • Nemjova K.
  • De clerck O.
  • Leliaert F.

Abstract

The green algal family Chlorochytriaceae comprises relatively large coccoid algae with secondarily thickened cell walls. Despite its morphological distinctness, the family remained molecularly uncharacterized. In this study, we investigated the morphology and phylogenetic position of 16 strains determined as members of two Chlorochytriaceae genera, Chlorochytrium and Scotinosphaera. The phylogenetic reconstructions were based on the analyses of two datasets, including a broad, concatenated alignment of SSU rDNA and rbcL sequences, and a 10-gene alignment of 32 selected taxa. All analyses revealed the distant relation of the two genera, segregated in two different classes: Chlorophyceae and Ulvophyceae. Chlorochytrium strains were inferred in two distinct clades of the Stephanosphaerinia clade within the Chlorophyceae. Whereas clade A morphologically fits the description of Chlorochytrium, the strains of clade B coincide with the circumscription of the genus Neospongiococcum. The Scotinosphaera strains formed a distinct and highly divergent clade within the Ulvophyceae, warranting the recognition of a new order, Scotinosphaerales. Morphologically, the order is characterized by large cells bearing local cell wall thickenings, pyrenoid matrix dissected by numerous anastomosing cytoplasmatic channels, sporogenesis comprising the accumulation of secondary carotenoids in the cell periphery and almost simultaneous cytokinesis. The close relationship of the Scotinosphaerales with other early diverging ulvophycean orders enforces the notion that non-motile unicellular freshwater organisms have played an important role in the early diversification of the Ulvophyceae.

Keywords

Chlorochytrium, Chlorophyceae, chloroplast, Kentrosphaera, phylogeny, Scotinosphaera, taxonomy, ultrastructure, Ulvophyceae

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  • Canonical resource URI: http://purl.org/phylo/treebase/phylows/study/TB2:S13318
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