Stramenopiles are a diverse but relatively well-studied eukaryotic supergroup with considerable genomic information available (Sibbald and Archibald, 2017). Nevertheless, the relationships between major stramenopile subgroups remain unresolved, in part due to a lack of data from small nanoflagellates that make up a lot of the genetic diversity of the group. This is most obvious in Bigyromonadea, which is one of four major stramenopile subgroups but represented by a single transcriptome. To examine the diversity of Bigyromonadea and how the lack of data affects the tree, we generated transcriptomes from seven novel bigyromonada species described in this study: Develocauda condao n. gen. n. sp., Develocanicus komovi n. gen. n. sp., Develocanicus vyazemskyi n. sp., Cubaremonas variflagellatum n. gen. n. sp., Pirsonia chemainus nom. prov., Feodosia pseudopoda nom. prov., and Koktebelia satura nom. prov. Both maximum likelihood and Bayesian phylogenomic trees based on a 247 gene-matrix recovered a monophyletic Bigyromonadea that includes two diverse subgroups, Developea and Pirsoniales, that were not previously related based on single gene trees. Maximum likelihood analyses show Bigyromonadea related to oomycetes, whereas Bayesian analyses and topology testing were inconclusive. We observed similarities between the novel bigyromonad species and motile zoospores of oomycetes in morphology and the ability to self-aggregate. Rare formation of pseudopods and fused cells were also observed, traits that are also found in members of labyrinthulomycetes, another osmotrophic stramenopiles. Furthermore, we report the first case of eukaryovory in the flagellated stages of Pirsoniales. These analyses reveal new diversity of Bigyromonadea, and altogether suggest their monophyly with oomycetes, collectively known as Pseudofungi, is the most likely topology of the stramenopile tree.

Department of Botany University of British Columbia Vancouver V6T 1Z4 British Columbia Canada

Institute of Evolutionary Biology Faculty of Biology Biological and Chemical Research Centre University of Warsaw Warsaw 02 089 Poland

Ocean EcoSystems Biology Group GEOMAR Helmholtz Centre for Ocean Research Kiel 24105 Germany; Institute of Parasitology Biology Centre Czech Academy of Sciences 370 05 České Budějovice Czech Republic

Papanin Institute for Biology of Inland Waters Russian Academy of Sciences Borok 152742 Russia

Citace poskytuje Crossref.org

Integrated overview of stramenopile ecology, taxonomy, and heterotrophic origin