title: Molecular identification of Nucleophaga terricolae sp. nov. (Rozellomycota), and new insights on the origin of the Microsporidia.
abstract: Microsporidia are widespread endoparasites of animals, including humans. They are characterized by highly modified morphological and genetic features that cause difficulties in elucidating their enigmatic origin and evolution. Recent advances, however, indicate that the Microsporidia have emerged from the Rozellomycota, forming together either the most basal lineage of the Fungi or its closer relative. The Rozellomycota comprise a huge diversity of uncultured environmental clones, with a very few known species endoparasitic of algae and water moulds, like the chytrid-like Rozella, and of free-living amoebae, like Nucleophaga and the microsporidia-like Paramicrosporidium. A possible ancestral microsporidium, Mitosporidium, has recently been described from the water flea Daphnia, since the phylogenomic reconstruction showed that it branches to the root of the microsporidian tree, while the genome analysis revealed a fungal-like nuclear genome and the persistence of a mitochondrial genome. Here we report the 18S rDNA molecular phylogeny of an additional microsporidium-like endoparasite of amoebae, which has a developmental cycle almost identical to that of Nucleophaga amoebae. Our results show that the endoparasite is closely related to N. amoebae, forming a distinct species, for which we propose the name Nucleophaga terricolae. Furthermore, the Nucleophaga lineage is recovered as sister to the Microsporidia while Mitosporidium turns out to be member of a well-supported group of environmental clones. These results raise the question about the actual ancestry of the Microsporidia within the Rozellomycota. A precise and robust phylogeny will require further comparative genomic studies of these various strains, and should also consider the primitive microsporidia, for which genetic data are still lacking, because all these organisms are essentially morphologically similar.
authors.affiliation: CHLAREAS Chlamydia Research Association Nancy, 12 rue du Maconnais, F-54500, Vandoeuvre-lès-Nancy, France. corsaro@gmx.fr.
authors.forename: Daniele
authors.initials: D
authors.lastname: Corsaro
authors.affiliation: Central Institute of the Federal Armed Forces Medical Services, P.O. Box 7340, 56070, Koblenz, Germany.
authors.forename: Rolf
authors.initials: R
authors.lastname: Michel
authors.affiliation: Molecular Parasitology, Institute of Specific Prophylaxis and Tropical Medicine, Medical University of Vienna, Kinderspitalgasse 15, 1095, Vienna, Austria.
authors.forename: Julia
authors.initials: J
authors.lastname: Walochnik
authors.affiliation: CHLAREAS Chlamydia Research Association Nancy, 12 rue du Maconnais, F-54500, Vandoeuvre-lès-Nancy, France.|Faculty of Medecine, Tredi Research Department, Technopôle de Nancy-Brabois, 9, Avenue de la Forêt de Haye, B.P. 184, 54505, Vandœuvre-lès-Nancy, France.
authors.forename: Danielle
authors.initials: D
authors.lastname: Venditti
authors.affiliation: Institut of Medical Microbiology, University of Duisburg-Essen, Virchowstr.179, 45147, Essen, Germany.
authors.forename: Karl-Dieter
authors.initials: KD
authors.lastname: Müller
authors.affiliation: Central Institute of the Federal Armed Forces Medical Services, P.O. Box 7340, 56070, Koblenz, Germany.
authors.forename: Bärbel
authors.initials: B
authors.lastname: Hauröder
authors.affiliation: IOW-Leibniz-Institute for Baltic Sea Research Warnemünde, Seestr. 15, Rostock, Germany.|Friedrich-Loeffler-Institute, Federal Research Institute for Animal Health, Institute of Diagnostic Virology, Südufer 10, 17493, Greifswald-Insel Riems, Germany.
authors.forename: Claudia
authors.initials: C
authors.lastname: Wylezich
mesh_terms: D000656:Amoeba / Q000382:microbiology*; D000818:Animals; D005075:Biological Evolution; D004275:DNA, Ribosomal / Q000235:genetics; D003621:Daphnia / Q000382:microbiology*; D019143:Evolution, Molecular; D023281:Genomics; D021861:Microsporidia, Unclassified / Q000145:classification* / Q000235:genetics*; D010802:Phylogeny; D012337:RNA, Ribosomal, 18S / Q000235:genetics
chemical_list: D004275:DNA, Ribosomal; D012337:RNA, Ribosomal, 18S
keywords: Amoebae; Endoparasite; Microsporidia; Nucleophaga; Rozellomycota