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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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2
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Angst P, Pombert JF, Ebert D, Fields PD. Near chromosome-level genome assembly of the microsporidium Hamiltosporidium tvaerminnensis. G3 (BETHESDA, MD.) 2023; 13:jkad185. [PMID: 37565496 PMCID: PMC10542269 DOI: 10.1093/g3journal/jkad185] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Accepted: 08/05/2023] [Indexed: 08/12/2023]
Abstract
Microsporidia are intracellular parasitic fungi whose genomes rank among the smallest of all known eukaryotes. A number of outstanding questions remain concerning the evolution of their large-scale variation in genome architecture, responsible for genome size variation of more than an order of magnitude. This genome report presents the first near-chromosomal assembly of a large-genome microsporidium, Hamiltosporidium tvaerminnensis. Combined Oxford Nanopore, Pacific Biosciences (PacBio), and Illumina sequencing led to a genome assembly of 17 contigs, 11 of which represent complete chromosomes. Our assembly is 21.64 Mb in length, has an N50 of 1.44 Mb, and consists of 39.56% interspersed repeats. We introduce a novel approach in microsporidia, PacBio Iso-Seq, as part of a larger annotation pipeline for obtaining high-quality annotations of 3,573 protein-coding genes. Based on direct evidence from the full-length Iso-Seq transcripts, we present evidence for alternative polyadenylation and variation in splicing efficiency, which are potential regulation mechanisms for gene expression in microsporidia. The generated high-quality genome assembly is a necessary resource for comparative genomics that will help elucidate the evolution of genome architecture in response to intracellular parasitism.
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Affiliation(s)
- Pascal Angst
- Department of Environmental Sciences, Zoology, University of Basel, Basel 4051, Switzerland
| | | | - Dieter Ebert
- Department of Environmental Sciences, Zoology, University of Basel, Basel 4051, Switzerland
| | - Peter D Fields
- Department of Environmental Sciences, Zoology, University of Basel, Basel 4051, Switzerland
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3
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Mascarenhas Dos Santos AC, Julian AT, Liang P, Juárez O, Pombert JF. Telomere-to-Telomere genome assemblies of human-infecting Encephalitozoon species. BMC Genomics 2023; 24:237. [PMID: 37142951 PMCID: PMC10158259 DOI: 10.1186/s12864-023-09331-3] [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: 01/19/2023] [Accepted: 04/25/2023] [Indexed: 05/06/2023] Open
Abstract
BACKGROUND Microsporidia are diverse spore forming, fungal-related obligate intracellular pathogens infecting a wide range of hosts. This diversity is reflected at the genome level with sizes varying by an order of magnitude, ranging from less than 3 Mb in Encephalitozoon species (the smallest known in eukaryotes) to more than 50 Mb in Edhazardia spp. As a paradigm of genome reduction in eukaryotes, the small Encephalitozoon genomes have attracted much attention with investigations revealing gene dense, repeat- and intron-poor genomes characterized by a thorough pruning of molecular functions no longer relevant to their obligate intracellular lifestyle. However, because no Encephalitozoon genome has been sequenced from telomere-to-telomere and since no methylation data is available for these species, our understanding of their overall genetic and epigenetic architectures is incomplete. METHODS In this study, we sequenced the complete genomes from telomere-to-telomere of three human-infecting Encephalitozoon spp. -E. intestinalis ATCC 50506, E. hellem ATCC 50604 and E. cuniculi ATCC 50602- using short and long read platforms and leveraged the data generated as part of the sequencing process to investigate the presence of epigenetic markers in these genomes. We also used a mixture of sequence- and structure-based computational approaches, including protein structure prediction, to help identify which Encephalitozoon proteins are involved in telomere maintenance, epigenetic regulation, and heterochromatin formation. RESULTS The Encephalitozoon chromosomes were found capped by TTAGG 5-mer telomeric repeats followed by telomere associated repeat elements (TAREs) flanking hypermethylated ribosomal RNA (rRNA) gene loci featuring 5-methylcytosines (5mC) and 5-hemimethylcytosines (5hmC), themselves followed by lesser methylated subtelomeres and hypomethylated chromosome cores. Strong nucleotide biases were identified between the telomeres/subtelomeres and chromosome cores with significant changes in GC/AT, GT/AC and GA/CT contents. The presence of several genes coding for proteins essential to telomere maintenance, epigenetic regulation, and heterochromatin formation was further confirmed in the Encephalitozoon genomes. CONCLUSION Altogether, our results strongly support the subtelomeres as sites of heterochromatin formation in Encephalitozoon genomes and further suggest that these species might shutdown their energy-consuming ribosomal machinery while dormant as spores by silencing of the rRNA genes using both 5mC/5hmC methylation and facultative heterochromatin formation at these loci.
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Affiliation(s)
| | | | - Pingdong Liang
- Department of Biology, Illinois Institute of Technology, Chicago, IL, USA
| | - Oscar Juárez
- Department of Biology, Illinois Institute of Technology, Chicago, IL, USA
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4
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Bunn DC, Miller N. Natural Occurrence and Analysis of Nosema sp. Infection in the Adult Population of Western Bean Cutworm in Michigan. ENVIRONMENTAL ENTOMOLOGY 2023; 52:39-46. [PMID: 36469425 DOI: 10.1093/ee/nvac102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Indexed: 06/17/2023]
Abstract
An understanding of population dynamics and insect biology is important for effective crop management strategies. Biotic factors such as pathogens play a large role on the fitness and dynamics of insect populations. Microsporidia are obligate intracellular parasites that infect more than 150 insect species and range from sublethal and chronic to fast acting and deadly. The western bean cutworm, Striacosta albicosta (Smith) (Lepidoptera: Noctuidae), is a pest of both corn (Zea maize L. [Poales: Poaceae]) and dry beans (Phaseolus sp L. [Fabales: Fabaceae]) that is infected by a microsporidian parasite from the genus Nosema (Microsporidia: Nosematidae). Unfortunately, little is known about the interactions between the Nosema sp. (Microsporidia: Nosematidae) infecting the western bean cutworm and its prevalence and effects on the host population. This is especially true for the western bean cutworm population that has settled in the Great Lakes region over the last two decades. Using field caught samples and phase contrast microscopy, no consistent trends in pathogen load were observed over the course of the western bean cutworm flight season. A weak, but statistically significant relationship was observed between male body weight and pathogen load. Overall, we found a 100% prevalence of infection in the adult western bean cutworm population in Michigan.
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Affiliation(s)
- Dakota C Bunn
- Department of Biological Sciences, Illinois Institute of Technology, Chicago, IL 60616, USA
| | - Nicholas Miller
- Department of Biological Sciences, Illinois Institute of Technology, Chicago, IL 60616, USA
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5
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High genetic variability of Nosema ceranae populations in Apis mellifera from East Asia compared to central Asia and the Americas. Biol Invasions 2022. [DOI: 10.1007/s10530-022-02835-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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6
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de Albuquerque NRM, Haag KL, Fields PD, Cabalzar A, Ben-Ami F, Pombert JF, Ebert D. A new microsporidian parasite, Ordospora pajunii sp. nov (Ordosporidae), of Daphnia longispina highlights the value of genomic data for delineating species boundaries. J Eukaryot Microbiol 2022; 69:e12902. [PMID: 35279911 DOI: 10.1111/jeu.12902] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Revised: 03/03/2022] [Accepted: 03/03/2022] [Indexed: 11/27/2022]
Abstract
Speciation is a complex and continuous process that makes the delineation of species boundaries a challenging task in particular in species with little morphological differentiation, such as parasites. In this case, the use of genomic data is often necessary, such as for the intracellular Microsporidian parasites. Here we characterize the genome of a gut parasite of the cladoceran Daphnia longispina (isolate FI-F-10), which we propose as a new species within the genus Ordospora: O. pajunii sp. nov (Ordosporidae). FI-F-10 closest relative, O. colligata is only found in D. magna. Both microsporidian species share several morphological features. Although it is not possible to estimate divergence times for Microsporidia due to the lack of fossil records and accelerated evolutionary rates, we base our proposal on the phylogenomic and genomic distances between both microsporidian lineages. Phylogenomic reconstruction shows that FI-F-10 forms an early diverging branch basal to the cluster that contains all known O. colligata strains. Whole-genome comparisons show that FI-F-10 presents a greater divergence at the sequence level than observed among O. colligata strains, and its genomic Average Nucleotide Identity (ANI) values against O. colligata are beyond the intra-specific range previously established for yeast and prokaryotes. Our data confirm that the ANI metrics are useful for fine genetic divergence calibration across Microsporidia taxa. In combination with phylogenetic and ecological data, genome-based metrics provide a powerful approach to delimitate species boundaries.
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Affiliation(s)
- Nathalia R M de Albuquerque
- Department of Genetics and Post-Graduation Program of Genetics and Molecular Biology, Federal University of Rio Grande do Sul, Av. Bento Gonçalves 9500, Porto Alegre, RS, 91501-970, Brazil
| | - Karen L Haag
- Department of Genetics and Post-Graduation Program of Genetics and Molecular Biology, Federal University of Rio Grande do Sul, Av. Bento Gonçalves 9500, Porto Alegre, RS, 91501-970, Brazil
| | - Peter D Fields
- Department of Environmental Sciences, Zoology, Basel University, Vesalgasse 1, 4051, Basel, Switzerland
| | - Andrea Cabalzar
- Department of Environmental Sciences, Zoology, Basel University, Vesalgasse 1, 4051, Basel, Switzerland
| | - Frida Ben-Ami
- School of Zoology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Jean-François Pombert
- Department of Biology, Illinois Institute of Technology, 3105 S Dearborn St, Chicago, IL, 60616, USA
| | - Dieter Ebert
- Department of Environmental Sciences, Zoology, Basel University, Vesalgasse 1, 4051, Basel, Switzerland
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7
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Angst P, Ebert D, Fields PD. Demographic history shapes genomic variation in an intracellular parasite with a wide geographic distribution. Mol Ecol 2022; 31:2528-2544. [DOI: 10.1111/mec.16419] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Revised: 02/14/2022] [Accepted: 02/28/2022] [Indexed: 11/27/2022]
Affiliation(s)
- Pascal Angst
- Department of Environmental Sciences, Zoology University of Basel Vesalgasse 1 4051 Basel Switzerland
| | - Dieter Ebert
- Department of Environmental Sciences, Zoology University of Basel Vesalgasse 1 4051 Basel Switzerland
| | - Peter D. Fields
- Department of Environmental Sciences, Zoology University of Basel Vesalgasse 1 4051 Basel Switzerland
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8
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Weng M, Xie D, Zhang Q, Li A, Zhang J. First report of Ovipleistophora ovariae and O. diplostomuri in China provides new insights into the intraspecific genetic variation and extends their distribution. Parasitology 2022; 149:314-324. [PMID: 35264262 PMCID: PMC11010532 DOI: 10.1017/s0031182021001852] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2021] [Revised: 10/07/2021] [Accepted: 10/17/2021] [Indexed: 11/07/2022]
Abstract
Microsporidia of the genus Ovipleistophora are generally parasites of fishes and aquatic crustaceans. In the current study, Ovipleistophora diplostomuri and O. ovariae were firstly reported from Culter alburnus and Xenocypris argentea and Parabramis pekinensis, respectively. Both of them exclusively infected fish ovary and were morphologically, ultrastructurally and genetically characterized. Sporogony occurred in direct contact with the host cell cytoplasm and sporophorous vesicles were not observed for the new isolates of these two Ovipleistophora species. Spores of O. ovariae were for the first time observed to be dimorphic. Genetic analysis indicated that the genetic variation in the ITS and LSU sequences was distinct among between-host O. diplostomuri isolates. High sequence variation in ITS sequence suggests that it can be a reliable molecular marker to explore the population genetics of O. diplostomuri. This is the first report of these two Ovipleistophora species in China which extends their host and geographical range.
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Affiliation(s)
- Meiqi Weng
- The Laboratory of Aquatic Parasitology, School of Marine Science and Engineering, Qingdao Agricultural University, 266237Qingdao, China
- Key Laboratory of Aquaculture Diseases Control, Ministry of Agriculture and State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan430072, China
- College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing10049, China
| | - Derong Xie
- The Laboratory of Aquatic Parasitology, School of Marine Science and Engineering, Qingdao Agricultural University, 266237Qingdao, China
- Key Laboratory of Aquaculture Diseases Control, Ministry of Agriculture and State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan430072, China
- College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing10049, China
| | - Qianqian Zhang
- Key Laboratory of Aquaculture Diseases Control, Ministry of Agriculture and State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan430072, China
| | - Aihua Li
- Key Laboratory of Aquaculture Diseases Control, Ministry of Agriculture and State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan430072, China
| | - Jinyong Zhang
- The Laboratory of Aquatic Parasitology, School of Marine Science and Engineering, Qingdao Agricultural University, 266237Qingdao, China
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9
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Williams BAP, Williams TA, Trew J. Comparative Genomics of Microsporidia. EXPERIENTIA SUPPLEMENTUM (2012) 2022; 114:43-69. [PMID: 35543998 DOI: 10.1007/978-3-030-93306-7_2] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The microsporidia are a phylum of intracellular parasites that represent the eukaryotic cell in a state of extreme reduction, with genomes and metabolic capabilities embodying eukaryotic cells in arguably their most streamlined state. Over the past 20 years, microsporidian genomics has become a rapidly expanding field starting with sequencing of the genome of Encephalitozoon cuniculi, one of the first ever sequenced eukaryotes, to the current situation where we have access to the data from over 30 genomes across 20+ genera. Reaching back further in evolutionary history, to the point where microsporidia diverged from other eukaryotic lineages, we now also have genomic data for some of the closest known relatives of the microsporidia such as Rozella allomycis, Metchnikovella spp. and Amphiamblys sp. Data for these organisms allow us to better understand the genomic processes that shaped the emergence of the microsporidia as a group. These intensive genomic efforts have revealed some of the processes that have shaped microsporidian cells and genomes including patterns of genome expansions and contractions through gene gain and loss, whole genome duplication, differential patterns of invasion and purging of transposable elements. All these processes have been shown to occur across short and longer time scales to give rise to a phylum of parasites with dynamic genomes with a diversity of sizes and organisations.
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Affiliation(s)
| | - Tom A Williams
- School of Biological Sciences, University of Bristol, Bristol, UK
| | - Jahcub Trew
- School of Biosciences, University of Exeter, Exeter, UK
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10
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Abstract
DNA repair is an important component of genome integrity and organisms with reduced repair capabilities tend to accumulate mutations at elevated rates. Microsporidia are intracellular parasites exhibiting high levels of genetic divergence postulated to originate from the lack of several proteins, including the heterotrimeric Rad9–Rad1–Hus1 DNA repair clamp. Microsporidian species from the Encephalitozoonidae have undergone severe streamlining with small genomes coding for about 2,000 proteins. The highly divergent sequences found in Microsporidia render functional inferences difficult such that roughly half of these 2,000 proteins have no known function. Using a structural homology-based annotation approach combining protein structure prediction and tridimensional similarity searches, we found that the Rad9–Rad1–Hus1 DNA clamp is present in Microsporidia, together with many other components of the DNA repair machinery previously thought to be missing from these organisms. Altogether, our results indicate that the DNA repair machinery is present and likely functional in Microsporidia.
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11
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Abstract
Microsporidia are obligate intracellular pathogens identified ∼150 years ago as the cause of pébrine, an economically important infection in silkworms. There are about 220 genera and 1,700 species of microsporidia, which are classified based on their ultrastructural features, developmental cycle, host-parasite relationship, and molecular analysis. Phylogenetic analysis suggests that microsporidia are related to the fungi, being grouped with the Cryptomycota as a basal branch or sister group to the fungi. Microsporidia can be transmitted by food and water and are likely zoonotic, as they parasitize a wide range of invertebrate and vertebrate hosts. Infection in humans occurs in both immunocompetent and immunodeficient hosts, e.g., in patients with organ transplantation, patients with advanced human immunodeficiency virus (HIV) infection, and patients receiving immune modulatory therapy such as anti-tumor necrosis factor alpha antibody. Clusters of infections due to latent infection in transplanted organs have also been demonstrated. Gastrointestinal infection is the most common manifestation; however, microsporidia can infect virtually any organ system, and infection has resulted in keratitis, myositis, cholecystitis, sinusitis, and encephalitis. Both albendazole and fumagillin have efficacy for the treatment of various species of microsporidia; however, albendazole has limited efficacy for the treatment of Enterocytozoon bieneusi. In addition, immune restoration can lead to resolution of infection. While the prevalence rate of microsporidiosis in patients with AIDS has fallen in the United States, due to the widespread use of combination antiretroviral therapy (cART), infection continues to occur throughout the world and is still seen in the United States in the setting of cART if a low CD4 count persists.
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12
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Huang Q, Wu ZH, Li WF, Guo R, Xu JS, Dang XQ, Ma ZG, Chen YP, Evans JD. Genome and Evolutionary Analysis of Nosema ceranae: A Microsporidian Parasite of Honey Bees. Front Microbiol 2021; 12:645353. [PMID: 34149635 PMCID: PMC8206274 DOI: 10.3389/fmicb.2021.645353] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Accepted: 04/29/2021] [Indexed: 01/18/2023] Open
Abstract
Microsporidia comprise a phylum of single cell, intracellular parasites and represent the earliest diverging branch in the fungal kingdom. The microsporidian parasite Nosema ceranae primarily infects honey bee gut epithelial cells, leading to impaired memory, suppressed host immune responses and colony collapse under certain circumstances. As the genome of N. ceranae is challenging to assembly due to very high genetic diversity and repetitive region, the genome was re-sequenced using long reads. We present a robust 8.8 Mbp genome assembly of 2,280 protein coding genes, including a high number of genes involved in transporting nutrients and energy, as well as drug resistance when compared with sister species Nosema apis. We also describe the loss of the critical protein Dicer in approximately half of the microsporidian species, giving new insights into the availability of RNA interference pathway in this group. Our results provided new insights into the pathogenesis of N. ceranae and a blueprint for treatment strategies that target this parasite without harming honey bees. The unique infectious apparatus polar filament and transportation pathway members can help to identify treatments to control this parasite.
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Affiliation(s)
- Qiang Huang
- Honeybee Research Institute, Jiangxi Agricultural University, Nanchang, China.,Jiangxi Province Key Laboratory of Honeybee Biology and Beekeeping, Jiangxi Agricultural University, Nanchang, China
| | - Zhi Hao Wu
- Honeybee Research Institute, Jiangxi Agricultural University, Nanchang, China.,Jiangxi Province Key Laboratory of Honeybee Biology and Beekeeping, Jiangxi Agricultural University, Nanchang, China
| | - Wen Feng Li
- Guangdong Key Laboratory of Animal Conservation and Resource Utilization, Guangdong Public Laboratory of Wild Animal Conservation and Utilization, Institute of Zoology, Guangdong Academy of Sciences, Guangzhou, China
| | - Rui Guo
- College of Animal Sciences (College of Bee Science), Fujian Agriculture and Forestry University, Fuzhou, China
| | - Jin Shan Xu
- College of Life Sciences, Chongqing Normal University, Chongqing, China
| | - Xiao Qun Dang
- College of Life Sciences, Chongqing Normal University, Chongqing, China
| | - Zheng Gang Ma
- College of Life Sciences, Chongqing Normal University, Chongqing, China
| | - Yan Ping Chen
- US Department of Agriculture-Aricultural Research Service (USDA-ARS) Bee Research Laboratory, Beltsville, MD, United States
| | - Jay D Evans
- US Department of Agriculture-Aricultural Research Service (USDA-ARS) Bee Research Laboratory, Beltsville, MD, United States
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13
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Wadi L, Reinke AW. Evolution of microsporidia: An extremely successful group of eukaryotic intracellular parasites. PLoS Pathog 2020; 16:e1008276. [PMID: 32053705 PMCID: PMC7017984 DOI: 10.1371/journal.ppat.1008276] [Citation(s) in RCA: 63] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Affiliation(s)
- Lina Wadi
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Aaron W. Reinke
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- * E-mail:
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14
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Haag KL, Pombert JF, Sun Y, de Albuquerque NRM, Batliner B, Fields P, Lopes TF, Ebert D. Microsporidia with Vertical Transmission Were Likely Shaped by Nonadaptive Processes. Genome Biol Evol 2020; 12:3599-3614. [PMID: 31825473 PMCID: PMC6944219 DOI: 10.1093/gbe/evz270] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/05/2019] [Indexed: 12/14/2022] Open
Abstract
Microsporidia have the leanest genomes among eukaryotes, and their physiological and genomic simplicity has been attributed to their intracellular, obligate parasitic life-style. However, not all microsporidia genomes are small or lean, with the largest dwarfing the smallest ones by at least an order of magnitude. To better understand the evolutionary mechanisms behind this genomic diversification, we explore here two clades of microsporidia with distinct life histories, Ordospora and Hamiltosporidium, parasitizing the same host species, Daphnia magna. Based on seven newly assembled genomes, we show that mixed-mode transmission (the combination of horizontal and vertical transmission), which occurs in Hamiltosporidium, is found to be associated with larger and AT-biased genomes, more genes, and longer intergenic regions, as compared with the exclusively horizontally transmitted Ordospora. Furthermore, the Hamiltosporidium genome assemblies contain a variety of repetitive elements and long segmental duplications. We show that there is an excess of nonsynonymous substitutions in the microsporidia with mixed-mode transmission, which cannot be solely attributed to the lack of recombination, suggesting that bursts of genome size in these microsporidia result primarily from genetic drift. Overall, these findings suggest that the switch from a horizontal-only to a mixed mode of transmission likely produces population bottlenecks in Hamiltosporidium species, therefore reducing the effectiveness of natural selection, and allowing their genomic features to be largely shaped by nonadaptive processes.
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Affiliation(s)
- Karen L Haag
- Department of Genetics and Post-Graduation Program of Genetics and Molecular Biology, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
| | | | - Yukun Sun
- Department of Biology, Illinois Institute of Technology
| | - Nathalia Rammé M de Albuquerque
- Department of Genetics and Post-Graduation Program of Genetics and Molecular Biology, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
| | | | - Peter Fields
- Department of Environmental Sciences, Zoology, Basel University, Switzerland
| | - Tiago Falcon Lopes
- Department of Genetics and Post-Graduation Program of Genetics and Molecular Biology, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
| | - Dieter Ebert
- Department of Environmental Sciences, Zoology, Basel University, Switzerland
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15
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Peters MJ, Suwannapong G, Pelin A, Corradi N. Genetic and Genome Analyses Reveal Genetically Distinct Populations of the Bee Pathogen Nosema ceranae from Thailand. MICROBIAL ECOLOGY 2019; 77:877-889. [PMID: 30288544 DOI: 10.1007/s00248-018-1268-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Accepted: 09/25/2018] [Indexed: 06/08/2023]
Abstract
The recent global decline in Western honeybee (Apis mellifera) populations is of great concern for pollination and honey production worldwide. Declining honeybee populations are frequently infected by the microsporidian pathogen Nosema ceranae. This species was originally described in the Asiatic honeybee (Apis cerana), and its identification in global A. mellifera hives could result from a recent host transfer. Recent genome studies have found that global populations of this parasite are polyploid and that humans may have fueled their global expansion. To better understand N. ceranae biology, we investigated its genetic diversity within part of their native range (Thailand) and among different hosts (A. mellifera, A. cerana) using both PCR and genome-based methods. We find that Thai N. ceranae populations share many SNPs with other global populations and appear to be clonal. However, in stark contrast with previous studies, we found that these populations also carry many SNPs not found elsewhere, indicating that these populations have evolved in their current geographic location for some time. Our genome analyses also indicate the potential presence of diploidy within Thai populations of N. ceranae.
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Affiliation(s)
- Melissa J Peters
- Department of Biology, University of Ottawa, Ottawa, Ontario, Canada
| | | | - Adrian Pelin
- Department of Biochemistry, University of Ottawa, Ottawa, Ontario, Canada
- Center for Cancer Therapeutics, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
| | - Nicolas Corradi
- Department of Biology, University of Ottawa, Ottawa, Ontario, Canada.
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Li W, Xiao L. Multilocus Sequence Typing and Population Genetic Analysis of Enterocytozoon bieneusi: Host Specificity and Its Impacts on Public Health. Front Genet 2019; 10:307. [PMID: 31001333 PMCID: PMC6454070 DOI: 10.3389/fgene.2019.00307] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Accepted: 03/20/2019] [Indexed: 01/13/2023] Open
Abstract
Microsporidia comprise a large class of unicellular eukaryotic pathogens that are medically and agriculturally important, but poorly understood. There have been nearly 1,500 microsporidian species described thus far, which are variable in biology, genetics, genomics, and host specificity. Among those, Enterocytozoon bieneusi is the well-known species responsible for the most recorded cases of human microsporidian affections. The pathogen can colonize a broad range of mammals and birds and most of the animals surveyed share some genotypes with humans, posing a threat to public health. Based on DNA sequence analysis of the ribosomal internal transcribed spacer (ITS) and phylogenetic analysis, several hundreds of E. bieneusi genotypes have been defined and clustered into different genetic groups with varied levels of host specificity. However, single locus-based typing using ITS might have insufficient resolution to discriminate among E. bieneusi isolates with complex genetic or hereditary characteristics and to assess the elusive reproduction or transmission modes of the organism, highlighting the need for exploration and application of multilocus sequence typing (MLST) and population genetic tools. The present review begins with a primer on microsporidia and major microsporidian species, briefly introduces the recent advances on E. bieneusi ITS genotyping and phylogeny, summarizes recent MLST and population genetic data, analyzes the inter- and intragroup host specificity at the MLST level, and interprets the public health implications of host specificity in zoonotic or cross-species transmission of this ubiquitous fungus.
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Affiliation(s)
- Wei Li
- Heilongjiang Key Laboratory for Zoonosis, College of Veterinary Medicine, Northeast Agricultural University, Harbin, China
| | - Lihua Xiao
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
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Petkova I, Abbey-Lee RN, Løvlie H. Parasite infection and host personality: Glugea-infected three-spined sticklebacks are more social. Behav Ecol Sociobiol 2018; 72:173. [PMID: 30369708 PMCID: PMC6182751 DOI: 10.1007/s00265-018-2586-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Revised: 09/20/2018] [Accepted: 09/24/2018] [Indexed: 01/04/2023]
Abstract
Abstract The existence of animal personality is now well-documented, although the causes and consequences of this phenomenon are still largely unclear. Parasite infection can have pervasive effects on hosts, including altering host behaviour, and may thus contribute to differences in host personality. We investigated the relationship between the three-spined stickleback and its common parasite Glugea anomala, with focus on differences in host personality. Naturally infected and uninfected individuals were assayed for the five personality traits activity, exploration, boldness, sociability, and aggression. If infected fish behaved differently from uninfected, to benefit this parasite with horizontal transmission, we predicted behaviour increasing interactions with other sticklebacks to increase. Infection status explained differences in host personality. Specifically, Glugea-infected individuals were more social than uninfected fish. This confirms a link between parasite infection and host behaviour, and a relationship which may improve the horizontal transmission of Glugea. However, future studies need to establish the consequences of this for the parasite, and the causality of the parasite-host personality relationship. Significance statement Parasite infection that alters host behaviour could be a possible avenue of research into the causes of animal personality. We studied the link between infection and personality using the three-spined stickleback and its parasite Glugea anomala. We predicted that infected individuals would be more prone to interact with other sticklebacks, since this would improve transmission of this parasite. The personality of uninfected and naturally infected fish was measured and we observed that Glugea-infected sticklebacks were more social. Our results confirm a link between parasitism and variation in host personality. Electronic supplementary material The online version of this article (10.1007/s00265-018-2586-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Irina Petkova
- Department of Physics, Chemistry and Biology, IFM Biology, Linköping University, SE-581 83 Linköping, Sweden
- School of Biological Sciences, Centre for Ecology, Evolution and Behaviour, Royal Holloway University of London, Egham, TW20 0EX UK
| | - Robin N. Abbey-Lee
- Department of Physics, Chemistry and Biology, IFM Biology, Linköping University, SE-581 83 Linköping, Sweden
| | - Hanne Løvlie
- Department of Physics, Chemistry and Biology, IFM Biology, Linköping University, SE-581 83 Linköping, Sweden
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Huang Q. Evolution of Dicer and Argonaute orthologs in microsporidian parasites. INFECTION GENETICS AND EVOLUTION 2018; 65:329-332. [PMID: 30142384 DOI: 10.1016/j.meegid.2018.08.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Revised: 07/18/2018] [Accepted: 08/13/2018] [Indexed: 11/28/2022]
Abstract
Microsporidia are a group of intracellular parasites which infect animal hosts. The infection can broadly influence the hosts' metabolism, growth as well as immune responses. Recently, a functional RNAi pathway was suggested from the microsporidia parasite Nosema ceranae, whereby the gene Dicer showed strong impact on spore proliferation. Based on sequenced microsporidian species, the RNAi gene orthologs have only been annotated for a few species. In order to study the selection of RNAi gene Dicer and Argonaute orthologs from microsporidian genomes, a phylogenetic analysis was performed based on single copy orthologs of 21 microsporidian parasite species. Of the 21 studied parasite species, 11 parasite species maintained Dicer and Argonaute orthologs, which were further used to build the gene trees. The gene Dicer and Argonaute orthologs were either both maintained or both lost. The topology structures between the phylogenetic Dicer, Argonaute and species trees were consistent. The results suggest that the gene Dicer and Argonaute were selected as a unit, which were selectively maintained/lost during the lineage divergence. The study provides general insights on the selection of RNAi pathway in microsporidian parasites and the evolution of parasitism.
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Affiliation(s)
- Qiang Huang
- Institute of Bee Health, Vetsuisse Faculty, University of Bern, Schwarzenburgstrasse 161, CH-3097 Liebefeld, Switzerland; Honey Bee Research Institute, Jiangxi Agricultural University, Zhimin Avenue 1101, 330045 Nanchang, China.
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Abstract
The kingdom Fungi comprises species that inhabit nearly all ecosystems. Fungi exist as both free-living and symbiotic unicellular and multicellular organisms with diverse morphologies. The genomes of fungi encode genes that enable them to thrive in diverse environments, invade plant and animal cells, and participate in nutrient cycling in terrestrial and aquatic ecosystems. The continuously expanding databases of fungal genome sequences have been generated by individual and large-scale efforts such as Génolevures, Broad Institute's Fungal Genome Initiative, and the 1000 Fungal Genomes Project (http://1000.fungalgenomes.org). These efforts have produced a catalog of fungal genes and genomic organization. The genomic datasets can be utilized to better understand how fungi have adapted to their lifestyles and ecological niches. Large datasets of fungal genomic and transcriptomic data have enabled the use of novel methodologies and improved the study of fungal evolution from a molecular sequence perspective. Combined with microscopes, petri dishes, and woodland forays, genome sequencing supports bioinformatics and comparative genomics approaches as important tools in the study of the biology and evolution of fungi.
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Buddenborg SK, Bu L, Zhang SM, Schilkey FD, Mkoji GM, Loker ES. Transcriptomic responses of Biomphalaria pfeifferi to Schistosoma mansoni: Investigation of a neglected African snail that supports more S. mansoni transmission than any other snail species. PLoS Negl Trop Dis 2017; 11:e0005984. [PMID: 29045404 PMCID: PMC5685644 DOI: 10.1371/journal.pntd.0005984] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Revised: 11/14/2017] [Accepted: 09/20/2017] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Biomphalaria pfeifferi is highly compatible with the widespread human-infecting blood fluke Schistosoma mansoni and transmits more cases of this parasite to people than any other snail species. For these reasons, B. pfeifferi is the world's most important vector snail for S. mansoni, yet we know relatively little at the molecular level regarding the interactions between B. pfeifferi and S. mansoni from early-stage sporocyst transformation to the development of cercariae. METHODOLOGY/PRINCIPAL FINDINGS We sought to capture a portrait of the response of B. pfeifferi to S. mansoni as it occurs in nature by undertaking Illumina dual RNA-Seq on uninfected control B. pfeifferi and three intramolluscan developmental stages (1- and 3-days post infection and patent, cercariae-producing infections) using field-derived west Kenyan specimens. A high-quality, well-annotated de novo B. pfeifferi transcriptome was assembled from over a half billion non-S. mansoni paired-end reads. Reads associated with potential symbionts were noted. Some infected snails yielded fewer normalized S. mansoni reads and showed different patterns of transcriptional response than others, an indication that the ability of field-derived snails to support and respond to infection is variable. Alterations in transcripts associated with reproduction were noted, including for the oviposition-related hormone ovipostatin and enzymes involved in metabolism of bioactive amines like dopamine or serotonin. Shedding snails exhibited responses consistent with the need for tissue repair. Both generalized stress and immune factors immune factors (VIgLs, PGRPs, BGBPs, complement C1q-like, chitinases) exhibited complex transcriptional responses in this compatible host-parasite system. SIGNIFICANCE This study provides for the first time a large sequence data set to help in interpreting the important vector role of the neglected snail B. pfeifferi in transmission of S. mansoni, including with an emphasis on more natural, field-derived specimens. We have identified B. pfeifferi targets particularly responsive during infection that enable further dissection of the functional role of these candidate molecules.
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Affiliation(s)
- Sarah K. Buddenborg
- Department of Biology, Center for Evolutionary and Theoretical Immunology, University of New Mexico, Albuquerque, New Mexico, United States of America
| | - Lijing Bu
- Department of Biology, Center for Evolutionary and Theoretical Immunology, University of New Mexico, Albuquerque, New Mexico, United States of America
| | - Si-Ming Zhang
- Department of Biology, Center for Evolutionary and Theoretical Immunology, University of New Mexico, Albuquerque, New Mexico, United States of America
| | - Faye D. Schilkey
- National Center for Genome Resources, Santa Fe, New Mexico, United States of America
| | - Gerald M. Mkoji
- Center for Biotechnology Research and Development, Kenya Medical Research Institute, Nairobi, KEN
| | - Eric S. Loker
- Department of Biology, Center for Evolutionary and Theoretical Immunology, University of New Mexico, Albuquerque, New Mexico, United States of America
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Dynamics of parasitophorous vacuoles formed by the microsporidian pathogen Encephalitozoon cuniculi. Fungal Genet Biol 2017; 107:20-23. [PMID: 28754285 DOI: 10.1016/j.fgb.2017.07.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Revised: 07/10/2017] [Accepted: 07/24/2017] [Indexed: 12/28/2022]
Abstract
It has been a long-standing debate if sexual development occurs in the microsporidian lineages. Previous studies, including morphological observations, ploidy analysis, and the presence of a sex-related locus, provided evidence of possible extant of sexual development. This study presents another line of evidence by monitoring the parasitophorous vacuoles (PVs) formed by Encephalitozoon cuniculi. Time lapse observations of infection cycles of E. cuniculi revealed that multiple PVs can be formed in a single host cell and the PVs in the single cell can merge (fusion) or split (fission). The dynamics of PVs may provide a route for interactions between genetically distinct microsporidian isolates during host infections.
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Abstract
Although at the level of resolution of genes and molecules most information about mating in fungi is from a single lineage, the Dikarya, many fundamental discoveries about mating in fungi have been made in the earlier branches of the fungi. These are nonmonophyletic groups that were once classified into the chytrids and zygomycetes. Few species in these lineages offer the potential of genetic tractability, thereby hampering the ability to identify the genes that underlie those fundamental insights. Research performed during the past decade has now established the genes required for mating type determination and pheromone synthesis in some species in the phylum Mucoromycota, especially in the order Mucorales. These findings provide striking parallels with the evolution of mating systems in the Dikarya fungi. Other discoveries in the Mucorales provide the first examples of sex-cell type identity being driven directly by a gene that confers mating type, a trait considered more of relevance to animal sex determination but difficult to investigate in animals. Despite these discoveries, there remains much to be gleaned about mating systems from these fungi.
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Li J, Gu F, Wu R, Yang J, Zhang KQ. Phylogenomic evolutionary surveys of subtilase superfamily genes in fungi. Sci Rep 2017; 7:45456. [PMID: 28358043 PMCID: PMC5371821 DOI: 10.1038/srep45456] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Accepted: 02/28/2017] [Indexed: 01/10/2023] Open
Abstract
Subtilases belong to a superfamily of serine proteases which are ubiquitous in fungi and are suspected to have developed distinct functional properties to help fungi adapt to different ecological niches. In this study, we conducted a large-scale phylogenomic survey of subtilase protease genes in 83 whole genome sequenced fungal species in order to identify the evolutionary patterns and subsequent functional divergences of different subtilase families among the main lineages of the fungal kingdom. Our comparative genomic analyses of the subtilase superfamily indicated that extensive gene duplications, losses and functional diversifications have occurred in fungi, and that the four families of subtilase enzymes in fungi, including proteinase K-like, Pyrolisin, kexin and S53, have distinct evolutionary histories which may have facilitated the adaptation of fungi to a broad array of life strategies. Our study provides new insights into the evolution of the subtilase superfamily in fungi and expands our understanding of the evolution of fungi with different lifestyles.
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Affiliation(s)
- Juan Li
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming, 650091, P.R. China
| | - Fei Gu
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming, 650091, P.R. China
| | - Runian Wu
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming, 650091, P.R. China
| | - JinKui Yang
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming, 650091, P.R. China
| | - Ke-Qin Zhang
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming, 650091, P.R. China
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Laurent B, Moinard M, Spataro C, Ponts N, Barreau C, Foulongne-Oriol M. Landscape of genomic diversity and host adaptation in Fusarium graminearum. BMC Genomics 2017; 18:203. [PMID: 28231761 PMCID: PMC5324198 DOI: 10.1186/s12864-017-3524-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Accepted: 01/27/2017] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Fusarium graminearum is one of the main causal agents of the Fusarium Head Blight, a worldwide disease affecting cereal cultures, whose presence can lead to contaminated grains with chemically stable and harmful mycotoxins. Resistant cultivars and fungicides are frequently used to control this pathogen, and several observations suggest an adaptation of F. graminearum that raises concerns regarding the future of current plant disease management strategies. To understand the genetic basis as well as the extent of its adaptive potential, we investigated the landscape of genomic diversity among six French isolates of F. graminearum, at single-nucleotide resolution using whole-genome re-sequencing. RESULTS A total of 242,756 high-confidence genetic variants were detected when compared to the reference genome, among which 96% are single nucleotides polymorphisms. One third of these variants were observed in all isolates. Seventy-seven percent of the total polymorphism is located in 32% of the total length of the genome, comprising telomeric/subtelomeric regions as well as discrete interstitial sections, delineating clear variant enriched genomic regions- 7.5 times in average. About 80% of all the F. graminearum protein-coding genes were found polymorphic. Biological functions are not equally affected: genes potentially involved in host adaptation are preferentially located within polymorphic islands and show greater diversification rate than genes fulfilling basal functions. We further identified 29 putative effector genes enriched with non-synonymous effect mutation. CONCLUSIONS Our results highlight a remarkable level of polymorphism in the genome of F. graminearum distributed in a specific pattern. Indeed, the landscape of genomic diversity follows a bi-partite organization of the genome according to polymorphism and biological functions. We measured, for the first time, the level of sequence diversity for the entire gene repertoire of F. graminearum and revealed that the majority are polymorphic. Those assumed to play a role in host-pathogen interaction are discussed, in the light of the subsequent consequences for host adaptation. The annotated genetic variants discovered for this major pathogen are valuable resources for further genetic and genomic studies.
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Affiliation(s)
- Benoit Laurent
- INRA, UR1264 Mycologie et Sécurité des Aliments, bâtiment Qualis, 71 avenue Edouard Bourlaux, CS 20032, F-33882, Villenave d'Ornon cedex, France
| | - Magalie Moinard
- INRA, UR1264 Mycologie et Sécurité des Aliments, bâtiment Qualis, 71 avenue Edouard Bourlaux, CS 20032, F-33882, Villenave d'Ornon cedex, France
| | - Cathy Spataro
- INRA, UR1264 Mycologie et Sécurité des Aliments, bâtiment Qualis, 71 avenue Edouard Bourlaux, CS 20032, F-33882, Villenave d'Ornon cedex, France
| | - Nadia Ponts
- INRA, UR1264 Mycologie et Sécurité des Aliments, bâtiment Qualis, 71 avenue Edouard Bourlaux, CS 20032, F-33882, Villenave d'Ornon cedex, France
| | - Christian Barreau
- INRA, UR1264 Mycologie et Sécurité des Aliments, bâtiment Qualis, 71 avenue Edouard Bourlaux, CS 20032, F-33882, Villenave d'Ornon cedex, France
| | - Marie Foulongne-Oriol
- INRA, UR1264 Mycologie et Sécurité des Aliments, bâtiment Qualis, 71 avenue Edouard Bourlaux, CS 20032, F-33882, Villenave d'Ornon cedex, France.
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Friedman S, Freitag M. Centrochromatin of Fungi. PROGRESS IN MOLECULAR AND SUBCELLULAR BIOLOGY 2017; 56:85-109. [PMID: 28840234 DOI: 10.1007/978-3-319-58592-5_4] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The centromere is an essential chromosomal locus that dictates the nucleation point for assembly of the kinetochore and subsequent attachment of spindle microtubules during chromosome segregation. Research over the last decades demonstrated that centromeres are defined by a combination of genetic and epigenetic factors. Recent work showed that centromeres are quite diverse and flexible and that many types of centromere sequences and centromeric chromatin ("centrochromatin") have evolved. The kingdom of the fungi serves as an outstanding example of centromere plasticity, including organisms with centromeres as diverse as 0.15-300 kb in length, and with different types of chromatin states for most species examined thus far. Some of the species in the less familiar taxa provide excellent opportunities to help us better understand centromere biology in all eukaryotes, which may improve treatment options against fungal infection, and biotechnologies based on fungi. This review summarizes the current knowledge of fungal centromeres and centrochromatin, including an outlook for future research.
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Affiliation(s)
- Steven Friedman
- Department of Biochemistry and Biophysics, Oregon State University, 2011 ALS Bldg, Corvallis, OR, 97331, USA
| | - Michael Freitag
- Department of Biochemistry and Biophysics, Oregon State University, 2011 ALS Bldg, Corvallis, OR, 97331, USA.
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26
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Frenette AP, Eydal M, Hansen H, Burt MDB, Duffy MS. Integrative Approach for the Reliable Detection and Specific Identification of the Microsporidium Loma morhua in Atlantic Cod (Gadus morhua). J Eukaryot Microbiol 2016; 64:67-77. [PMID: 27317934 DOI: 10.1111/jeu.12339] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Revised: 06/04/2016] [Accepted: 06/14/2016] [Indexed: 11/29/2022]
Abstract
Microsporidia are fungal parasites that infect diverse invertebrate and vertebrate hosts. Finfish aquaculture supports epizootics due to high host density and the high biotic potential of these parasites. Reliable methods for parasite detection and identification are a necessary precursor to empirical assessment of strategies to mitigate the effects of these pathogens during aquaculture. We developed an integrative approach to detect and identify Loma morhua infecting Atlantic cod. We show that the spleen is more reliable than the commonly presumed gills as best organ for parasite detection in spite of substantial morphological plasticity in xenoma complexes. We developed rDNA primers with 100% sensitivity in detecting L. morhua and with utility in distinguishing some congeneric Loma species. ITS sequencing is necessary to distinguish L. morhua from other congeneric microsporidia due to intraspecific nucleotide variation. 64% of L. morhua ITS variants from Atlantic cod have a 9-nucleotide motif that distinguishes it from Loma spp. infecting non-Gadus hosts. The remaining 36% of ITS variants from Atlantic cod are distinguished from currently represented Loma spp., particularly those infecting Gadus hosts, based on a 14-nucleotide motif. This research approach is amenable to developing templates in support of reliable detection and identification of other microsporidian parasites in fishes.
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Affiliation(s)
- Aaron P Frenette
- Department of Biology, University of New Brunswick, Fredericton, NB, E3B 5A3, Canada
| | - Matthías Eydal
- Institute for Experimental Pathology at Keldur, University of Iceland, Keldnavegur 3, 112, Reykjavik, Iceland
| | - Haakon Hansen
- Norwegian Veterinary Institute, Ullevalsveien 68, Pb 750 Sentrum, N-0106, Oslo, Norway
| | - Michael D B Burt
- Department of Biology, University of New Brunswick, Fredericton, NB, E3B 5A3, Canada
| | - Michael S Duffy
- Department of Biology, University of New Brunswick, Fredericton, NB, E3B 5A3, Canada
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27
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González-Tortuero E, Rusek J, Maayan I, Petrusek A, Piálek L, Laurent S, Wolinska J. Genetic diversity of two Daphnia-infecting microsporidian parasites, based on sequence variation in the internal transcribed spacer region. Parasit Vectors 2016; 9:293. [PMID: 27206473 PMCID: PMC4875737 DOI: 10.1186/s13071-016-1584-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Accepted: 05/10/2016] [Indexed: 11/12/2022] Open
Abstract
Background Microsporidia are spore-forming obligate intracellular parasites that include both emerging pathogens and economically important disease agents. However, little is known about the genetic diversity of microsporidia. Here, we investigated patterns of geographic population structure, intraspecific genetic variation, and recombination in two microsporidian taxa that commonly infect cladocerans of the Daphnia longispina complex in central Europe. Taken together, this information helps elucidate the reproductive mode and life-cycles of these parasite species. Methods Microsporidia-infected Daphnia were sampled from seven drinking water reservoirs in the Czech Republic. Two microsporidia species (Berwaldia schaefernai and microsporidium lineage MIC1) were sequenced at the internal transcribed spacer (ITS) region, using the 454 pyrosequencing platform. Geographical structure analyses were performed applying Fisher’s exact tests, analyses of molecular variance, and permutational MANOVA. To evaluate the genetic diversity of the ITS region, the number of polymorphic sites and Tajima’s and Watterson’s estimators of theta were calculated. Tajima’s D was also used to determine if the ITS in these taxa evolved neutrally. Finally, neighbour similarity score and pairwise homology index tests were performed to detect recombination events. Results While there was little variation among Berwaldia parasite strains infecting different host populations, the among-population genetic variation of MIC1 was significant. Likewise, ITS genetic diversity was lower in Berwaldia than in MIC1. Recombination signals were detected only in Berwaldia. Conclusion Genetic tests showed that parasite populations could have expanded recently after a bottleneck or that the ITS could be under negative selection in both microsporidia species. Recombination analyses might indicate cryptic sex in Berwaldia and pure asexuality in MIC1. The differences observed between the two microsporidian species present an exciting opportunity to study the genetic basis of microsporidia-Daphnia coevolution in natural populations, and to better understand reproduction in these parasites. Electronic supplementary material The online version of this article (doi:10.1186/s13071-016-1584-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Enrique González-Tortuero
- Department of Ecosystem Research, Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Müggelseedamm 301, 12587, Berlin, Germany. .,Berlin Centre for Genomics in Biodiversity Research (BeGenDiv), Königin-Luise-Straße 6-8, 14195, Berlin, Germany. .,Department of Biology II, Ludwig Maximilians University, Großhaderner Straße 2, 82512, Planegg-Martinsried, Germany.
| | - Jakub Rusek
- Department of Biology II, Ludwig Maximilians University, Großhaderner Straße 2, 82512, Planegg-Martinsried, Germany
| | - Inbar Maayan
- Department of Biology II, Ludwig Maximilians University, Großhaderner Straße 2, 82512, Planegg-Martinsried, Germany
| | - Adam Petrusek
- Department of Ecology, Faculty of Science, Charles University in Prague, Viničná 7, 128 44, Prague, Czech Republic
| | - Lubomír Piálek
- Department of Ecology, Faculty of Science, Charles University in Prague, Viničná 7, 128 44, Prague, Czech Republic.,Department of Zoology, Faculty of Science, University of South Bohemia, Branišovská 31, 370 05, České Budějovice, Czech Republic
| | - Stefan Laurent
- School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland.,Swiss Institute of Bioinformatics (SIB), 1015, Lausanne, Switzerland
| | - Justyna Wolinska
- Department of Ecosystem Research, Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Müggelseedamm 301, 12587, Berlin, Germany.,Department of Biology, Chemistry and Pharmacy, Institute of Biology, Free University of Berlin, Königin-Luise-Straße 1-3, 14195, Berlin, Germany
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28
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Williams TA, Nakjang S, Campbell SE, Freeman MA, Eydal M, Moore K, Hirt RP, Embley TM, Williams BAP. A Recent Whole-Genome Duplication Divides Populations of a Globally Distributed Microsporidian. Mol Biol Evol 2016; 33:2002-15. [PMID: 27189558 PMCID: PMC4948709 DOI: 10.1093/molbev/msw083] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The Microsporidia are a major group of intracellular fungi and important parasites of animals including insects, fish, and immunocompromised humans. Microsporidian genomes have undergone extreme reductive evolution but there are major differences in genome size and structure within the group: some are prokaryote-like in size and organisation (<3 Mb of gene-dense sequence) while others have more typically eukaryotic genome architectures. To gain fine-scale, population-level insight into the evolutionary dynamics of these tiny eukaryotic genomes, we performed the broadest microsporidian population genomic study to date, sequencing geographically isolated strains of Spraguea, a marine microsporidian infecting goosefish worldwide. Our analysis revealed that population structure across the Atlantic Ocean is associated with a conserved difference in ploidy, with American and Canadian isolates sharing an ancestral whole genome duplication that was followed by widespread pseudogenisation and sorting-out of paralogue pairs. While past analyses have suggested de novo gene formation of microsporidian-specific genes, we found evidence for the origin of new genes from noncoding sequence since the divergence of these populations. Some of these genes experience selective constraint, suggesting the evolution of new functions and local host adaptation. Combining our data with published microsporidian genomes, we show that nucleotide composition across the phylum is shaped by a mutational bias favoring A and T nucleotides, which is opposed by an evolutionary force favoring an increase in genomic GC content. This study reveals ongoing dramatic reorganization of genome structure and the evolution of new gene functions in modern microsporidians despite extensive genomic streamlining in their common ancestor.
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Affiliation(s)
- Tom A Williams
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Sirintra Nakjang
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Scott E Campbell
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Devon, United Kingdom
| | - Mark A Freeman
- Ross University School of Veterinary Medicine, St. Kitts, West Indies
| | - Matthías Eydal
- Institute for Experimental Pathology, University of Iceland, Keldur, Iceland
| | - Karen Moore
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Devon, United Kingdom
| | - Robert P Hirt
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - T Martin Embley
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Bryony A P Williams
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Devon, United Kingdom
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Pelin A, Moteshareie H, Sak B, Selman M, Naor A, Eyahpaise MÈ, Farinelli L, Golshani A, Kvac M, Corradi N. The genome of an Encephalitozoon cuniculi type III strain reveals insights into the genetic diversity and mode of reproduction of a ubiquitous vertebrate pathogen. Heredity (Edinb) 2016; 116:458-65. [PMID: 26837273 DOI: 10.1038/hdy.2016.4] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Revised: 12/10/2015] [Accepted: 12/18/2015] [Indexed: 02/07/2023] Open
Abstract
Encephalitozoon cuniculi is a model microsporidian species with a mononucleate nucleus and a genome that has been extensively studied. To date, analyses of genome diversity have revealed the existence of four genotypes in E. cuniculi (EcI, II, III and IV). Genome sequences are available for EcI, II and III, and are all very divergent, possibly diploid and genetically homogeneous. The mechanisms that cause low genetic diversity in E. cuniculi (for example, selfing, inbreeding or a combination of both), as well as the degree of genetic variation in their natural populations, have been hard to assess because genome data have been so far gathered from laboratory-propagated strains. In this study, we aim to tackle this issue by analyzing the complete genome sequence of a natural strain of E. cuniculi isolated in 2013 from a steppe lemming. The strain belongs to the EcIII genotype and has been designated EcIII-L. The EcIII-L genome sequence harbors genomic features intermediate to known genomes of II and III lab strains, and we provide primers that differentiate the three E. cuniculi genotypes using a single PCR. Surprisingly, the EcIII-L genome is also highly homogeneous, harbors signatures of heterozygosity and also one strain-specific single-nucleotide polymorphism (SNP) that introduces a stop codon in a key meiosis gene, Spo11. Functional analyses using a heterologous system demonstrate that this SNP leads to a deficient meiosis in a model fungus. This indicates that EcIII-L meiotic machinery may be presently broken. Overall, our findings reveal previously unsuspected genome diversity in E. cuniculi, some of which appears to affect genes of primary importance for the biology of this pathogen.
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Affiliation(s)
- A Pelin
- Department of Biology, Canadian Institute for Advanced Research, University of Ottawa, Ottawa, ON, Canada
| | - H Moteshareie
- Department of Biology, Carleton University, Ottawa, Ontario, Canada.,Ottawa Institute of Systems Biology, Carleton University, Ottawa, Ontario, Canada
| | - B Sak
- Institute of Parasitology, Biology Centre of the Academy of Sciences of the Czech Republic, České Budějovice, Czech Republic
| | - M Selman
- Department of Biology, Canadian Institute for Advanced Research, University of Ottawa, Ottawa, ON, Canada
| | - A Naor
- Department of Biology, Canadian Institute for Advanced Research, University of Ottawa, Ottawa, ON, Canada
| | - M-È Eyahpaise
- Department of Biology, Canadian Institute for Advanced Research, University of Ottawa, Ottawa, ON, Canada
| | - L Farinelli
- FASTERIS S.A., Ch. du Pont-du-Centenaire 109, Plan-les-Ouates, Switzerland
| | - A Golshani
- Department of Biology, Carleton University, Ottawa, Ontario, Canada.,Ottawa Institute of Systems Biology, Carleton University, Ottawa, Ontario, Canada
| | - M Kvac
- Institute of Parasitology, Biology Centre of the Academy of Sciences of the Czech Republic, České Budějovice, Czech Republic
| | - N Corradi
- Department of Biology, Canadian Institute for Advanced Research, University of Ottawa, Ottawa, ON, Canada
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30
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Bernal CE, Zorro MM, Sierra J, Gilchrist K, Botero JH, Baena A, Ramirez-Pineda JR. Encephalitozoon intestinalis Inhibits Dendritic Cell Differentiation through an IL-6-Dependent Mechanism. Front Cell Infect Microbiol 2016; 6:4. [PMID: 26870700 PMCID: PMC4735406 DOI: 10.3389/fcimb.2016.00004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 01/12/2016] [Indexed: 01/03/2023] Open
Abstract
Microsporidia are a group of intracellular pathogens causing self-limited and severe diseases in immunocompetent and immunocompromised individuals, respectively. A cellular type 1 adaptive response, mediated by IL-12, IFNγ, CD4+, and CD8+ T cells has been shown to be essential for host resistance, and dendritic cells (DC) play a key role at eliciting anti-microsporidial immunity. We investigated the in vitro response of DC and DC precursors/progenitors to infection with Encephalitozoon intestinalis (Ei), a common agent of human microsporidosis. Ei-exposed DC cultures up-regulated the surface expression of MHC class II and the costimulatory molecules CD86 and CD40, only when high loads of spores were used. A vigorous secretion of IL-6 but not of IL-1β or IL-12p70 was also observed in these cultures. Ei-exposed DC cultures consisted of immature infected and mature bystander DC, as assessed by MHC class II and costimulatory molecules expression, suggesting that intracellular Ei spores deliver inhibitory signals in DC. Moreover, Ei selectively inhibited the secretion of IL-12p70 in LPS-stimulated DC. Whereas Ei-exposed DC promoted allogeneic naïve T cell proliferation and IL-2 and IFNγ secretion in DC-CD4+ T cell co-cultures, separated co-cultures with bystander or infected DCs showed stimulation or inhibition of IFNγ secretion, respectively. When DC precursors/progenitors were exposed to Ei spores, a significant inhibition of DC differentiation was observed without shifting the development toward cells phenotypically or functionally compatible with myeloid-derived suppressor cells. Neutralization experiments demonstrated that this inhibitory effect is IL-6-dependent. Altogether this investigation reveals a novel potential mechanism of immune escape of microsporidian parasites through the modulation of DC differentiation and maturation.
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Affiliation(s)
- Carmen E Bernal
- Grupo Inmunomodulación, Universidad de AntioquiaMedellín, Colombia; Grupo de Parasitología, Universidad de AntioquiaMedellín, Colombia
| | - Maria M Zorro
- Grupo Inmunomodulación, Universidad de Antioquia Medellín, Colombia
| | - Jelver Sierra
- Grupo Inmunomodulación, Universidad de Antioquia Medellín, Colombia
| | | | - Jorge H Botero
- Grupo de Parasitología, Universidad de Antioquia Medellín, Colombia
| | - Andres Baena
- Grupo de Inmunología Celular e Inmunogenética, Universidad de AntioquiaMedellín, Colombia; Departamento de Microbiología y Parasitología, Universidad de AntioquiaMedellín, Colombia
| | - Jose R Ramirez-Pineda
- Grupo Inmunomodulación, Universidad de AntioquiaMedellín, Colombia; Corporación Académica para el Estudio de Patologías Tropicales, Facultad de Medicina, Universidad de AntioquiaMedellín, Colombia
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31
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Dia N, Lavie L, Faye N, Méténier G, Yeramian E, Duroure C, Toguebaye BS, Frutos R, Niang MN, Vivarès CP, Ben Mamoun C, Cornillot E. Subtelomere organization in the genome of the microsporidian Encephalitozoon cuniculi: patterns of repeated sequences and physicochemical signatures. BMC Genomics 2016; 17:34. [PMID: 26744270 PMCID: PMC4704409 DOI: 10.1186/s12864-015-1920-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Accepted: 09/11/2015] [Indexed: 12/23/2022] Open
Abstract
Background The microsporidian Encephalitozoon cuniculi is an obligate intracellular eukaryotic pathogen with a small nuclear genome (2.9 Mbp) consisting of 11 chromosomes. Although each chromosome end is known to contain a single rDNA unit, the incomplete assembly of subtelomeric regions following sequencing of the genome identified only 3 of the 22 expected rDNA units. While chromosome end assembly remains a difficult process in most eukaryotic genomes, it is of significant importance for pathogens because these regions encode factors important for virulence and host evasion. Results Here we report the first complete assembly of E. cuniculi chromosome ends, and describe a novel mosaic structure of segmental duplications (EXT repeats) in these regions. EXT repeats range in size between 3.5 and 23.8 kbp and contain four multigene families encoding membrane associated proteins. Twenty-one recombination sites were identified in the sub-terminal region of E. cuniculi chromosomes. Our analysis suggests that these sites contribute to the diversity of chromosome ends organization through Double Strand Break repair mechanisms. The region containing EXT repeats at chromosome extremities can be differentiated based on gene composition, GC content, recombination sites density and chromosome landscape. Conclusion Together this study provides the complete structure of the chromosome ends of E. cuniculi GB-M1, and identifies important factors, which could play a major role in parasite diversity and host-parasite interactions. Comparison with other eukaryotic genomes suggests that terminal regions could be distinguished precisely based on gene content, genetic instability and base composition biais. The diversity of processes assciated with chromosome extremities and their biological consequences, as they are presented in the present study, emphasize the fact that great effort will be necessary in the future to characterize more carefully these regions during whole genome sequencing efforts. Electronic supplementary material The online version of this article (doi:10.1186/s12864-015-1920-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Ndongo Dia
- Unité de Virologie Médicale, Institut Pasteur de Dakar, 36 Avenue Pasteur, B.P. 220, Dakar, Sénégal.
| | - Laurence Lavie
- Clermont Université, Université Blaise Pascal, Laboratoire Microorganismes, Génome et Environnement, UMR 6023, CNRS, 63177, Aubière, France.
| | - Ngor Faye
- Laboratoire de Parasitologie Générale, Département de Biologie Animale, Faculté des Sciences et Technologies, Université Cheikh Anta Diop, Dakar, Sénégal.
| | - Guy Méténier
- Clermont Université, Université Blaise Pascal, Laboratoire Microorganismes, Génome et Environnement, UMR 6023, CNRS, 63177, Aubière, France.
| | - Edouard Yeramian
- Unité de Bioinformatique Structurale, UMR 3528 CNRS, Institut Pasteur, 25-28, rue du Dr Roux, 75015, Paris, France.
| | - Christophe Duroure
- Laboratoire de Météorologie Physique, OPGC UMR 6016 CNRS-Université Blaise Pascal, 24 Avenue des Landais, 63177, Aubière Cedex, France.
| | - Bhen S Toguebaye
- Laboratoire de Parasitologie Générale, Département de Biologie Animale, Faculté des Sciences et Technologies, Université Cheikh Anta Diop, Dakar, Sénégal.
| | - Roger Frutos
- CIRAD, UMR 17, Cirad-Ird, TA-A17/G, Campus International de Baillarguet, 34398, Montpellier, France.
| | - Mbayame N Niang
- Unité de Virologie Médicale, Institut Pasteur de Dakar, 36 Avenue Pasteur, B.P. 220, Dakar, Sénégal.
| | - Christian P Vivarès
- Clermont Université, Université Blaise Pascal, Laboratoire Microorganismes, Génome et Environnement, UMR 6023, CNRS, 63177, Aubière, France.
| | - Choukri Ben Mamoun
- Section of Infectious Disease and Department of Microbial Pathogenesis, Winchester Building WWW403D, Yale School of Medicine, 15 York St., New Haven, CT, 06520, USA.
| | - Emmanuel Cornillot
- Institut de Recherche en Cancérologie de Montpellier, IRCM - INSERM U1194 & Université de Montpellier & ICM, Institut régional du Cancer Montpellier, Campus Val d'Aurelle, 34298, Montpellier cedex 5, France. .,Institut de Biologie Computationnelle, IBC, Campus Saint Priest, 34090, Montpellier, France.
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Schill KM, Wang Y, Butler RR, Pombert JF, Reddy NR, Skinner GE, Larkin JW. Genetic Diversity of Clostridium sporogenes PA 3679 Isolates Obtained from Different Sources as Resolved by Pulsed-Field Gel Electrophoresis and High-Throughput Sequencing. Appl Environ Microbiol 2016; 82:384-93. [PMID: 26519392 PMCID: PMC4702626 DOI: 10.1128/aem.02616-15] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Accepted: 10/21/2015] [Indexed: 12/27/2022] Open
Abstract
Clostridium sporogenes PA 3679 is a nonpathogenic, nontoxic model organism for proteolytic Clostridium botulinum used in the validation of conventional thermal food processes due to its ability to produce highly heat-resistant endospores. Because of its public safety importance, the uncertain taxonomic classification and genetic diversity of PA 3679 are concerns. Therefore, isolates of C. sporogenes PA 3679 were obtained from various sources and characterized using pulsed-field gel electrophoresis (PFGE) and whole-genome sequencing. The phylogenetic relatedness and genetic variability were assessed based on 16S rRNA gene sequencing and whole-genome single nucleotide polymorphism (SNP) analysis. All C. sporogenes PA 3679 isolates were categorized into two clades (clade I containing ATCC 7955 NCA3679 isolates 1961-2, 1990, and 2007 and clade II containing PA 3679 isolates NFL, UW, FDA, and Campbell and ATCC 7955 NCA3679 isolate 1961-4). The 16S maximum likelihood (ML) tree clustered both clades within proteolytic C. botulinum strains, with clade I forming a distinct cluster with other C. sporogenes non-PA 3679 strains. SNP analysis revealed that clade I isolates were more similar to the genomic reference PA 3679 (NCTC8594) genome (GenBank accession number AGAH00000000.1) than clade II isolates were. The genomic reference C. sporogenes PA 3679 (NCTC8594) genome and clade I C. sporogenes isolates were genetically distinct from those obtained from other sources (University of Wisconsin, National Food Laboratory, U.S. Food and Drug Administration, and Campbell's Soup Company). Thermal destruction studies revealed that clade I isolates were more sensitive to high temperature than clade II isolates were. Considering the widespread use of C. sporogenes PA 3679 and its genetic information in numerous studies, the accurate identification and genetic characterization of C. sporogenes PA 3679 are of critical importance.
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Affiliation(s)
- Kristin M Schill
- Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration, Bedford Park, Illinois, USA
| | - Yun Wang
- Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration, Bedford Park, Illinois, USA
| | - Robert R Butler
- Illinois Institute of Technology, Department of Biology, Chicago, Illinois, USA
| | | | - N Rukma Reddy
- Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration, Bedford Park, Illinois, USA
| | - Guy E Skinner
- Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration, Bedford Park, Illinois, USA
| | - John W Larkin
- Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration, Bedford Park, Illinois, USA
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33
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Maside X, Gómez-Moracho T, Jara L, Martín-Hernández R, De la Rúa P, Higes M, Bartolomé C. Population Genetics of Nosema apis and Nosema ceranae: One Host (Apis mellifera) and Two Different Histories. PLoS One 2015; 10:e0145609. [PMID: 26720131 PMCID: PMC4699903 DOI: 10.1371/journal.pone.0145609] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Accepted: 12/07/2015] [Indexed: 12/26/2022] Open
Abstract
Two microsporidians are known to infect honey bees: Nosema apis and Nosema ceranae. Whereas population genetics data for the latter have been released in the last few years, such information is still missing for N. apis. Here we analyze the patterns of nucleotide polymorphism at three single-copy loci (PTP2, PTP3 and RPB1) in a collection of Apis mellifera isolates from all over the world, naturally infected either with N. apis (N = 22) or N. ceranae (N = 23), to provide new insights into the genetic diversity, demography and evolution of N. apis, as well as to compare them with evidence from N. ceranae. Neutral variation in N. apis and N. ceranae is of the order of 1%. This amount of diversity suggests that there is no substantial differentiation between the genetic content of the two nuclei present in these parasites, and evidence for genetic recombination provides a putative mechanism for the flow of genetic information between chromosomes. The analysis of the frequency spectrum of neutral variants reveals a significant surplus of low frequency variants, particularly in N. ceranae, and suggests that the populations of the two pathogens are not in mutation-drift equilibrium and that they have experienced a population expansion. Most of the variation in both species occurs within honey bee colonies (between 62%-90% of the total genetic variance), although in N. apis there is evidence for differentiation between parasites isolated from distinct A. mellifera lineages (20%-34% of the total variance), specifically between those collected from lineages A and C (or M). This scenario is consistent with a long-term host-parasite relationship and contrasts with the lack of differentiation observed among host-lineages in N. ceranae (< 4% of the variance), which suggests that the spread of this emergent pathogen throughout the A. mellifera worldwide population is a recent event.
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Affiliation(s)
- Xulio Maside
- Medicina Xenómica, CIMUS, Universidade de Santiago de Compostela, Santiago de Compostela, Galicia, Spain
- Xenómica Comparada de Parásitos Humanos, IDIS, Santiago de Compostela, Galicia, Spain
- Departamento de Anatomía Patolóxica e Ciencias Forenses, Universidade de Santiago de Compostela, Santiago de Compostela, Galicia, Spain
| | - Tamara Gómez-Moracho
- Medicina Xenómica, CIMUS, Universidade de Santiago de Compostela, Santiago de Compostela, Galicia, Spain
- Xenómica Comparada de Parásitos Humanos, IDIS, Santiago de Compostela, Galicia, Spain
- Laboratorio de Patología Apícola. Centro de Investigación Apícola y Agroambiental (CIAPA), Instituto Regional de Investigación y Desarrollo Agroalimentario y Forestal (IRIAF), Consejería de Agricultura de la Junta de Comunidades de Castilla-La Mancha, Marchamalo, Guadalajara, Spain
| | - Laura Jara
- Departamento de Zoología y Antropología Física, Facultad de Veterinaria, Universidad de Murcia, Murcia, Spain
| | - Raquel Martín-Hernández
- Laboratorio de Patología Apícola. Centro de Investigación Apícola y Agroambiental (CIAPA), Instituto Regional de Investigación y Desarrollo Agroalimentario y Forestal (IRIAF), Consejería de Agricultura de la Junta de Comunidades de Castilla-La Mancha, Marchamalo, Guadalajara, Spain
- Instituto de Recursos Humanos para la Ciencia y la Tecnología (INCRECYT-FEDER), Fundación Parque Científico y Tecnológico de Albacete, Albacete, Spain
| | - Pilar De la Rúa
- Departamento de Zoología y Antropología Física, Facultad de Veterinaria, Universidad de Murcia, Murcia, Spain
| | - Mariano Higes
- Laboratorio de Patología Apícola. Centro de Investigación Apícola y Agroambiental (CIAPA), Instituto Regional de Investigación y Desarrollo Agroalimentario y Forestal (IRIAF), Consejería de Agricultura de la Junta de Comunidades de Castilla-La Mancha, Marchamalo, Guadalajara, Spain
| | - Carolina Bartolomé
- Medicina Xenómica, CIMUS, Universidade de Santiago de Compostela, Santiago de Compostela, Galicia, Spain
- Xenómica Comparada de Parásitos Humanos, IDIS, Santiago de Compostela, Galicia, Spain
- * E-mail:
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Xiang H, Zhang R, Butler RR, Liu T, Zhang L, Pombert JF, Zhou Z. Comparative Analysis of Codon Usage Bias Patterns in Microsporidian Genomes. PLoS One 2015; 10:e0129223. [PMID: 26057384 PMCID: PMC4461291 DOI: 10.1371/journal.pone.0129223] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Accepted: 05/06/2015] [Indexed: 12/29/2022] Open
Abstract
The sub-3 Mbp genomes from microsporidian species of the Encephalitozoon genus are the smallest known among eukaryotes and paragons of genomic reduction and compaction in parasites. However, their diminutive stature is not characteristic of all Microsporidia, whose genome sizes vary by an order of magnitude. This large variability suggests that different evolutionary forces are applied on the group as a whole. In this study, we have compared the codon usage bias (CUB) between eight taxonomically distinct microsporidian genomes: Encephalitozoon intestinalis, Encephalitozoon cuniculi, Spraguea lophii, Trachipleistophora hominis, Enterocytozoon bieneusi, Nematocida parisii, Nosema bombycis and Nosema ceranae. While the CUB was found to be weak in all eight Microsporidia, nearly all (98%) of the optimal codons in S. lophii, T. hominis, E. bieneusi, N. parisii, N. bombycis and N. ceranae are fond of A/U in third position whereas most (64.6%) optimal codons in the Encephalitozoon species E. intestinalis and E. cuniculi are biased towards G/C. Although nucleotide composition biases are likely the main factor driving the CUB in Microsporidia according to correlation analyses, directed mutational pressure also likely affects the CUB as suggested by ENc-plots, correspondence and neutrality analyses. Overall, the Encephalitozoon genomes were found to be markedly different from the other microsporidians and, despite being the first sequenced representatives of this lineage, are uncharacteristic of the group as a whole. The disparities observed cannot be attributed solely to differences in host specificity and we hypothesize that other forces are at play in the lineage leading to Encephalitozoon species.
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Affiliation(s)
- Heng Xiang
- College of Animal Science and Technology, Southwest University, Chongqing 400715, China
- * E-mail: (HX); (ZYZ)
| | - Ruizhi Zhang
- Biotechnology Research Center, Southwest University, Chongqing 400715, China
| | - Robert R. Butler
- Department of Biological and Chemical Sciences, Illinois Institute of Technology, Chicago, Illinois, United States of America
| | - Tie Liu
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400715, China
| | - Li Zhang
- Department of Math and Information, China West Normal University, Nanchong, Sichuan 637000, China
| | - Jean-François Pombert
- Department of Biological and Chemical Sciences, Illinois Institute of Technology, Chicago, Illinois, United States of America
| | - Zeyang Zhou
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400715, China
- * E-mail: (HX); (ZYZ)
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Desjardins CA, Sanscrainte ND, Goldberg JM, Heiman D, Young S, Zeng Q, Madhani HD, Becnel JJ, Cuomo CA. Contrasting host-pathogen interactions and genome evolution in two generalist and specialist microsporidian pathogens of mosquitoes. Nat Commun 2015; 6:7121. [PMID: 25968466 PMCID: PMC4435813 DOI: 10.1038/ncomms8121] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Accepted: 04/07/2015] [Indexed: 12/14/2022] Open
Abstract
Obligate intracellular pathogens depend on their host for growth yet must also evade detection by host defenses. Here we investigate host adaptation in two Microsporidia, the specialist Edhazardia aedis and the generalist Vavraia culicis, pathogens of disease vector mosquitoes. Genomic analysis and deep RNA-Seq across infection time courses reveal fundamental differences between these pathogens. E. aedis retains enhanced cell surface modification and signalling capacity, upregulating protein trafficking and secretion dynamically during infection. V. culicis is less dependent on its host for basic metabolites and retains a subset of spliceosomal components, with a transcriptome broadly focused on growth and replication. Transcriptional profiling of mosquito immune responses reveals that response to infection by E. aedis differs dramatically depending on the mode of infection, and that antimicrobial defensins may play a general role in mosquito defense against Microsporidia. This analysis illuminates fundamentally different evolutionary paths and host interplay of specialist and generalist pathogens.
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Affiliation(s)
| | - Neil D Sanscrainte
- USDA, ARS, Center for Medical, Agricultural and Veterinary Entomology, 1600 SW 23rd Drive, Gainesville, Florida 32608, USA
| | | | - David Heiman
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, USA
| | - Sarah Young
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, USA
| | - Qiandong Zeng
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, USA
| | - Hiten D Madhani
- Department of Biochemistry and Biophysics, University of California-San Francisco, San Francisco, California 94158, USA
| | - James J Becnel
- USDA, ARS, Center for Medical, Agricultural and Veterinary Entomology, 1600 SW 23rd Drive, Gainesville, Florida 32608, USA
| | - Christina A Cuomo
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, USA
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The Ordospora colligata genome: Evolution of extreme reduction in microsporidia and host-to-parasite horizontal gene transfer. mBio 2015; 6:mBio.02400-14. [PMID: 25587016 PMCID: PMC4313915 DOI: 10.1128/mbio.02400-14] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
UNLABELLED Microsporidia are a group of obligate intracellular parasites that are best known for their unique infection mechanism and their unparalleled levels of genomic reduction and compaction. We sequenced the genome of Ordospora colligata, a gut parasite of the microcrustacean Daphnia sp. and the closest known relative to the microsporidia characterized by the most extreme genomic reduction, the model genus Encephalitozoon. We found that the O. colligata genome is as compact as those of Encephalitozoon spp., featuring few introns and a similar complement of about 2,000 genes, altogether showing that the extreme reduction took place before the origin of Encephalitozoon spp. and their adaptation to vertebrate hosts. We also found that the O. colligata genome has acquired by horizontal transfer from its animal host a septin that is structurally analogous to septin 7, a protein that plays a major role in the endocytosis-based invasion mechanism of the fungal pathogen Candida albicans. Microsporidian invasion is most often characterized by injection through a projectile tube, but microsporidia are also known to invade cells by inducing endocytosis. Given the function of septins in other systems, we hypothesize that the acquired septin could help O. colligata induce its uptake by mimicking host receptors. IMPORTANCE The smallest known eukaryotic genomes are found in members of the Encephalitozoon genus of microsporidian parasites. Their extreme compaction, however, is not characteristic of the group, whose genomes can differ by an order of magnitude. The processes and evolutionary forces that led the Encephalitozoon genomes to shed so much of their ancestral baggage are unclear. We sequenced the genome of Ordospora colligata, a parasite of the water flea Daphnia sp. and the closest known relative of Encephalitozoon species, and show that this extreme reduction predated the split between the two lineages. We also found that O. colligata has acquired a septin gene by host-to-parasite horizontal transfer and predicted that the encoded protein folds like a septin 7, which plays a major role in endocytosis. We hypothesize that this acquisition could help O. colligata parasitize its hosts by facilitating endocytic infection, a mechanism that occurs in microsporidia but that is not yet well understood.
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Variability in minimal genomes: analysis of tandem repeats in the microsporidia Encephalitozoon intestinalis. INFECTION GENETICS AND EVOLUTION 2013; 20:26-33. [PMID: 23917025 DOI: 10.1016/j.meegid.2013.07.024] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2013] [Revised: 07/23/2013] [Accepted: 07/24/2013] [Indexed: 12/25/2022]
Abstract
Microsporidia are ubiquitous fungi with genomes that have undergone a strong reduction to the extreme cases of Encephalitozoon cuniculi and Encephalitozoon intestinalis. Genetic variability within species of the Encephalitozoon genus has been reported, with most of the studies based on the internal transcribed spacer (ITS) of the rDNA. However, in contrast to the picture of E. cuniculi and Encephalitozoon hellem, where different strains have been identified, no genetic variability has yet been observed in E. intestinalis. We have analysed tandem repeats included in putative coding sequences which could be used as polymorphic markers in E. intestinalis. Eight candidate loci (M2, M2A, M3, M5, M7, M7A, M8 and PTP1) were established and 9 E. intestinalis cultured strains from North America, South America and Europe were analysed. M2, M7 and PTP1 nucleotide sequences were identical among the different strains and the GenBank sequence. In contrast, we observed variants in 4 markers (M2A, M3, M7A and M8) which did not correspond to their respective reference sequences. The most noticeable finding was that with the M5 marker two genotypes were defined among the different strains studied, demonstrating genotypic variability of E. intestinalis. Although the diversity described is certainly not high, which can be explained by a lower chance of genetic variability in its minimal genome, we have demonstrated that polymorphisms actually exist in E. intestinalis. Epidemiological studies using this genetic marker should now be conducted to elucidate the genetic variability in E. intestinalis and improve our knowledge of the epidemiology of this microsporidia.
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Polonais V, Belkorchia A, Roussel M, Peyretaillade E, Peyret P, Diogon M, Delbac F. Identification of two new polar tube proteins related to polar tube protein 2 in the microsporidian Antonospora locustae. FEMS Microbiol Lett 2013; 346:36-44. [PMID: 23763358 DOI: 10.1111/1574-6968.12198] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2013] [Revised: 05/28/2013] [Accepted: 06/07/2013] [Indexed: 01/25/2023] Open
Abstract
Microsporidia are obligate intracellular eukaryotic parasites with a broad host spectrum characterized by a unique and highly sophisticated invasion apparatus, the polar tube (PT). In a previous study, two PT proteins, named AlPTP1 (50 kDa) and AlPTP2 (35 kDa), were identified in Antonospora locustae, an orthoptera parasite that is used as a biological control agent against locusts. Antibodies raised against AlPTP2 cross-reacted with a band migrating at ~70 kDa, suggesting that this 70-kDa antigen is closely related to AlPTP2. A blastp search against the A. locustae genome database allowed the identification of two further PTP2-like proteins named AlPTP2b (568 aa) and AlPTP2c (599 aa). Both proteins are characterized by a specific serine- and glycine-rich N-terminal extension with elastomeric structural features and share a common C-terminal end conserved with AlPTP2 (~88% identity for the last 250 aa). MS analysis of the 70-kDa band revealed the presence of AlPTP2b. Specific anti-AlPTP2b antibodies labelled the extruded PTs of the A. locustae spores, confirming that this antigen is a PT component. Finally, we showed that several PTP2-like proteins are also present in other phylogenetically related insect microsporidia, including Anncaliia algerae and Paranosema grylli.
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Affiliation(s)
- Valérie Polonais
- Clermont Université, Université d'Auvergne, Laboratoire Microorganismes: Génome et Environnement, Clermont-ferrand, France
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Grisdale CJ, Bowers LC, Didier ES, Fast NM. Transcriptome analysis of the parasite Encephalitozoon cuniculi: an in-depth examination of pre-mRNA splicing in a reduced eukaryote. BMC Genomics 2013; 14:207. [PMID: 23537046 PMCID: PMC3629993 DOI: 10.1186/1471-2164-14-207] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2012] [Accepted: 03/18/2013] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND The microsporidian Encephalitozoon cuniculi possesses one of the most reduced and compacted eukaryotic genomes. Reduction in this intracellular parasite has affected major cellular machinery, including the loss of over fifty core spliceosomal components compared to S. cerevisiae. To identify expression changes throughout the parasite's life cycle and also to assess splicing in the context of this reduced system, we examined the transcriptome of E. cuniculi using Illumina RNA-seq. RESULTS We observed that nearly all genes are expressed at three post-infection time-points examined. A large fraction of genes are differentially expressed between the first and second (37.7%) and first and third (43.8%) time-points, while only four genes are differentially expressed between the latter two. Levels of intron splicing are very low, with 81% of junctions spliced at levels below 50%. This is dramatically lower than splicing levels found in two other fungal species examined. We also describe the first case of alternative splicing in a microsporidian, an unexpected complexity given the reduction in spliceosomal components. CONCLUSIONS Low levels of splicing observed are likely the result of an inefficient spliceosome; however, at least in one case, splicing appears to be playing a functional role. Although several RNA decay genes are encoded in E. cuniculi, the lack of a few key players could be reducing decay levels and therefore increasing the proportion of unspliced transcripts. Significant proportions of genes are differentially expressed in the first forty-eight hours but not after, indicative of genetic changes that precede the intracellular to infective stage transition.
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Affiliation(s)
- Cameron J Grisdale
- Biodiversity Research Centre and Department of Botany, University of British Columbia, Vancouver, British Columbia, Canada
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Extremely reduced levels of heterozygosity in the vertebrate pathogen Encephalitozoon cuniculi. EUKARYOTIC CELL 2013; 12:496-502. [PMID: 23376943 DOI: 10.1128/ec.00307-12] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The genomes of microsporidia in the genus Encephalitozoon have been extensively studied for their minimalistic features, but they have seldom been used to investigate basic characteristics of the biology of these organisms, such as their ploidy or their mode of reproduction. In the present study, we aimed to tackle this issue by mapping Illumina sequence reads against the genomes of four strains of E. cuniculi. This approach, combined with more conventional molecular biology techniques, resulted in the identification of heterozygosity in all strains investigated, a typical signature of a diploid nuclear state. In sharp contrast with similar studies recently performed on a distant microsporidian lineage (Nematocida spp.), the level of heterozygosity that we identified across the E. cuniculi genomes was found to be extremely low. This reductive intraindividual genetic variation could result from the long-term propagation of these strains under laboratory conditions, but we propose that it could also reflect an intrinsic capacity of these vertebrate pathogens to self-reproduce.
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