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Hiltunen Thorén M, Onuț-Brännström I, Alfjorden A, Pecková H, Swords F, Hooper C, Holzer AS, Bass D, Burki F. Comparative genomics of Ascetosporea gives new insight into the evolutionary basis for animal parasitism in Rhizaria. BMC Biol 2024; 22:103. [PMID: 38702750 PMCID: PMC11069148 DOI: 10.1186/s12915-024-01898-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Accepted: 04/22/2024] [Indexed: 05/06/2024] Open
Abstract
BACKGROUND Ascetosporea (Endomyxa, Rhizaria) is a group of unicellular parasites infecting aquatic invertebrates. They are increasingly being recognized as widespread and important in marine environments, causing large annual losses in invertebrate aquaculture. Despite their importance, little molecular data of Ascetosporea exist, with only two genome assemblies published to date. Accordingly, the evolutionary origin of these parasites is unclear, including their phylogenetic position and the genomic adaptations that accompanied the transition from a free-living lifestyle to parasitism. Here, we sequenced and assembled three new ascetosporean genomes, as well as the genome of a closely related amphizoic species, to investigate the phylogeny, origin, and genomic adaptations to parasitism in Ascetosporea. RESULTS Using a phylogenomic approach, we confirm the monophyly of Ascetosporea and show that Paramyxida group with Mikrocytida, with Haplosporida being sister to both groups. We report that the genomes of these parasites are relatively small (12-36 Mb) and gene-sparse (~ 2300-5200 genes), while containing surprisingly high amounts of non-coding sequence (~ 70-90% of the genomes). Performing gene-tree aware ancestral reconstruction of gene families, we demonstrate extensive gene losses at the origin of parasitism in Ascetosporea, primarily of metabolic functions, and little gene gain except on terminal branches. Finally, we highlight some functional gene classes that have undergone expansions during evolution of the group. CONCLUSIONS We present important new genomic information from a lineage of enigmatic but important parasites of invertebrates and illuminate some of the genomic innovations accompanying the evolutionary transition to parasitism in this lineage. Our results and data provide a genetic basis for the development of control measures against these parasites.
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Affiliation(s)
- Markus Hiltunen Thorén
- Department of Organismal Biology, Uppsala University, Norbyv. 18D, Uppsala, SE-752 36, Sweden.
- Present Address: Department of Ecology, Environment and Plant Sciences, Stockholm University, Svante Arrhenius V. 20 A, Stockholm, SE-114 18, Sweden.
- Present Address: The Royal Swedish Academy of Sciences, Stockholm, SE-114 18, Sweden.
| | - Ioana Onuț-Brännström
- Present Address: Department of Ecology and Genetics, Uppsala University, Norbyv. 18D, Uppsala, SE-752 36, Sweden
- Present Address: Natural History Museum, Oslo University, Oslo, 0562, Norway
| | - Anders Alfjorden
- Department of Organismal Biology, Uppsala University, Norbyv. 18D, Uppsala, SE-752 36, Sweden
| | - Hana Pecková
- Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, Branišovská 31, České Budějovice, 370 05, Czech Republic
| | - Fiona Swords
- Marine Institute, Rinville, Oranmore, H91R673, Ireland
| | - Chantelle Hooper
- Centre for Environment, Fisheries and Aquaculture Science (Cefas), Weymouth Laboratory, Weymouth, Dorset, DT4 8UB, UK
- Sustainable Aquaculture Futures, Biosciences, University of Exeter, Stocker Road, Exeter, EX4 4QD, UK
| | - Astrid S Holzer
- Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, Branišovská 31, České Budějovice, 370 05, Czech Republic
- Division of Fish Health, University of Veterinary Medicine, Veterinärplatz 1, Vienna, 1210, Austria
| | - David Bass
- Centre for Environment, Fisheries and Aquaculture Science (Cefas), Weymouth Laboratory, Weymouth, Dorset, DT4 8UB, UK
- Sustainable Aquaculture Futures, Biosciences, University of Exeter, Stocker Road, Exeter, EX4 4QD, UK
- Natural History Museum (NHM), Science, London, SW7 5BD, UK
| | - Fabien Burki
- Department of Organismal Biology, Uppsala University, Norbyv. 18D, Uppsala, SE-752 36, Sweden.
- Science for Life Laboratory, Uppsala University, Uppsala, Sweden.
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Khalaf A, Lawniczak MKN, Blaxter ML, Jaron KS. Polyploidy is widespread in Microsporidia. Microbiol Spectr 2024; 12:e0366923. [PMID: 38214524 PMCID: PMC10845963 DOI: 10.1128/spectrum.03669-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Accepted: 12/15/2023] [Indexed: 01/13/2024] Open
Abstract
Microsporidia are obligate intracellular eukaryotic parasites with an extremely broad host range. They have both economic and public health importance. Ploidy in microsporidia is variable, with a few species formally identified as diploid and one as polyploid. Given the increase in the number of studies sequencing microsporidian genomes, it is now possible to assess ploidy levels across all currently explored microsporidian diversity. We estimate ploidy for all microsporidian data sets available on the Sequence Read Archive using k-mer-based analyses, indicating that polyploidy is widespread in Microsporidia and that ploidy change is dynamic in the group. Using genome-wide heterozygosity estimates, we also show that polyploid microsporidian genomes are relatively homozygous, and we discuss the implications of these findings on the timing of polyploidization events and their origin.IMPORTANCEMicrosporidia are single-celled intracellular parasites, distantly related to fungi, that can infect a broad range of hosts, from humans all the way to protozoans. Exploiting the wealth of microsporidian genomic data available, we use k-mer-based analyses to assess ploidy status across the group. Understanding a genome's ploidy is crucial in order to assemble it effectively and may also be relevant for better understanding a parasite's behavior and life cycle. We show that tetraploidy is present in at least six species in Microsporidia and that these polyploidization events are likely to have occurred independently. We discuss why these findings may be paradoxical, given that Microsporidia, like other intracellular parasites, have extremely small, reduced genomes.
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Affiliation(s)
- Amjad Khalaf
- Tree of Life, Wellcome Sanger Institute, Cambridge, United Kingdom
| | | | - Mark L. Blaxter
- Tree of Life, Wellcome Sanger Institute, Cambridge, United Kingdom
| | - Kamil S. Jaron
- Tree of Life, Wellcome Sanger Institute, Cambridge, United Kingdom
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Senderskiy IV, Dolgikh VV, Ismatullaeva DA, Mirzakhodjaev BA, Nikitina AP, Pankratov DL. Treatment of Microsporidium Nosema bombycis Spores with the New Antiseptic M250 Helps to Avoid Bacterial and Fungal Contamination of Infected Cultures without Affecting Parasite Polar Tube Extrusion. Microorganisms 2024; 12:154. [PMID: 38257981 PMCID: PMC10819227 DOI: 10.3390/microorganisms12010154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Revised: 01/08/2024] [Accepted: 01/10/2024] [Indexed: 01/24/2024] Open
Abstract
Microsporidia are a group of widespread eukaryotic spore-forming intracellular parasites of great economic and scientific importance. Since microsporidia cannot be cultured outside of a host cell, the search for new antimicrosporidian drugs requires an effective antiseptic to sterilize microsporidian spores to infect cell lines. Here, we show that a new polyhexamethylene guanidine derivative M250, which is active against fungi and bacteria at a concentration of 0.5-1 mg/L, is more than 1000 times less effective against spores of the microsporidium Nosema bombycis, a highly virulent pathogen of the silkworm Bombyx mori (LC50 is 0.173%). Treatment of N. bombycis spores that were isolated non-sterilely from silkworm caterpillars with 0.1% M250 solution does not reduce the rate of spore polar tube extrusion. However, it completely prevents contamination of the Sf-900 III cell culture medium by microorganisms in the presence of antibiotics. The addition of untreated spores to the medium results in contamination, whether antibiotics are present or not. Since 0.1% M250 does not affect spore discharging, this compound may be promising for preventing bacterial and fungal contamination of microsporidia-infected cell cultures.
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Affiliation(s)
- Igor V. Senderskiy
- All-Russian Institute of Plant Protection, Podbelsky Chausse 3, 196608 Saint-Petersburg, Russia;
| | - Viacheslav V. Dolgikh
- All-Russian Institute of Plant Protection, Podbelsky Chausse 3, 196608 Saint-Petersburg, Russia;
| | - Diloram A. Ismatullaeva
- Scientific Research Institute of Sericulture, Ipakchi Str. 1, Tashkent 100069, Uzbekistan; (D.A.I.); (B.A.M.)
| | - Bakhtiyar A. Mirzakhodjaev
- Scientific Research Institute of Sericulture, Ipakchi Str. 1, Tashkent 100069, Uzbekistan; (D.A.I.); (B.A.M.)
| | - Anastasiia P. Nikitina
- Department of Microbiology and Virology, Pavlov First Saint-Petersburg State Medical University, L’vaTolstogo Str. 6-8, 197022 Saint-Petersburg, Russia; (A.P.N.); (D.L.P.)
| | - Danil L. Pankratov
- Department of Microbiology and Virology, Pavlov First Saint-Petersburg State Medical University, L’vaTolstogo Str. 6-8, 197022 Saint-Petersburg, Russia; (A.P.N.); (D.L.P.)
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