1
|
Abstract
Microsporidia have drastically modified genomes and cytology resulting from their high level of adaptation to intracytoplasmic parasitism. Their origins, which had long remained enigmatic, were placed within the line of Rozella, a primitive endoparasitic chytrid. These origins became more and more refined with the discovery of various parasites morphologically similar to the primitive lines of microsporidia (Metchnikovellids and Chytridiopsids) but which possess fungal-like genomes and functional mitochondria. These various parasites turn out to be distinct missing links between a large assemblage of chytrid-like rozellids and the true microsporidians, which are actually a very evolved branch of the rozellids themselves. The question of how to consider the historically known Microsporidia and the various microsporidia-like organisms within paraphyletic rozellids is discussed.
Collapse
Affiliation(s)
- Daniele Corsaro
- CHLAREAS Chlamydia Research Association, Vandoeuvre-lès-Nancy, France.
| |
Collapse
|
2
|
Bass D, Czech L, Williams BAP, Berney C, Dunthorn M, Mahé F, Torruella G, Stentiford GD, Williams TA. Clarifying the Relationships between Microsporidia and Cryptomycota. J Eukaryot Microbiol 2018; 65:773-782. [PMID: 29603494 PMCID: PMC6282948 DOI: 10.1111/jeu.12519] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Revised: 03/02/2018] [Accepted: 03/20/2018] [Indexed: 01/27/2023]
Abstract
Some protists with microsporidian-like cell biological characters, including Mitosporidium, Paramicrosporidium, and Nucleophaga, have SSU rRNA gene sequences that are much less divergent than canonical Microsporidia. We analysed the phylogenetic placement and environmental diversity of microsporidian-like lineages that group near the base of the fungal radiation and show that they group in a clade with metchnikovellids and canonical microsporidians, to the exclusion of the clade including Rozella, in line with what is currently known of their morphology and cell biology. These results show that the phylogenetic scope of Microsporidia has been greatly underestimated. We propose that much of the lineage diversity previously thought to be cryptomycotan/rozellid is actually microsporidian, offering new insights into the evolution of the highly specialized parasitism of canonical Microsporidia. This insight has important implications for our understanding of opisthokont evolution and ecology, and is important for accurate interpretation of environmental diversity. Our analyses also demonstrate that many opisthosporidian (aphelid+rozellid+microsporidian) SSU V4 OTUs from Neotropical forest soils group with the short-branching Microsporidia, consistent with the abundance of their protist and arthropod hosts in soils. This novel diversity of Microsporidia provides a unique opportunity to investigate the evolutionary origins of a highly specialized clade of major animal parasites.
Collapse
Affiliation(s)
- David Bass
- Pathology and Microbial Systematics Theme, Centre for Environment, Fisheries and Aquaculture Science (Cefas), Barrack Road, The Nothe, Weymouth, DT4 8UB, UK.,Department of Life Sciences, The Natural History Museum, London, SW7 5BD, UK
| | - Lucas Czech
- Heidelberg Institute for Theoretical Studies, Schloß-Wolfsbrunnenweg, Heidelberg, 69118, Germany
| | - Bryony A P Williams
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter, EX4 4QD, UK
| | - Cédric Berney
- Sorbonne Université & CNRS, UMR 7144 (AD2M), Station Biologique de Roscoff, Place Georges Teissier, Roscoff, 29680, France
| | - Micah Dunthorn
- Department of Ecology, University of Kaiserslautern, Kaiserslautern, Germany
| | | | - Guifré Torruella
- Ecologie Systématique Evolution, CNRS, Université Paris-Sud, AgroParisTech, Université Paris-Saclay, Orsay, France
| | - Grant D Stentiford
- Pathology and Microbial Systematics Theme, Centre for Environment, Fisheries and Aquaculture Science (Cefas), Barrack Road, The Nothe, Weymouth, DT4 8UB, UK
| | - Tom A Williams
- School of Biological Sciences, University of Bristol, 24 Tyndall Avenue, Bristol, BS8 1TQ, UK
| |
Collapse
|
3
|
Corsaro D, Michel R, Walochnik J, Venditti D, Müller KD, Hauröder B, Wylezich C. Molecular identification of Nucleophaga terricolae sp. nov. (Rozellomycota), and new insights on the origin of the Microsporidia. Parasitol Res 2016; 115:3003-11. [PMID: 27075306 DOI: 10.1007/s00436-016-5055-9] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Accepted: 04/07/2016] [Indexed: 12/12/2022]
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.
Collapse
|