scholarly journals Comparative multi-omics analyses reveal differential expression of key genes relevant for parasitism between non-encapsulated and encapsulated Trichinella

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Xiaolei Liu ◽  
Yayan Feng ◽  
Xue Bai ◽  
Xuelin Wang ◽  
Rui Qin ◽  
...  
Keyword(s):  
Cell Formation ◽  
Invasion Biology ◽  
Gene Families ◽  
Dnase Ii ◽  
Genomic Correlation ◽  
Glutathione S Transferases ◽  
Differential Expansion ◽  
Genome Assemblies ◽  
Host Parasite ◽  
S Genes

AbstractGenome assemblies provide a powerful basis of comparative multi-omics analyses that offer insight into parasite pathogenicity, host-parasite interactions, and invasion biology. As a unique intracellular nematode, Trichinella consists of two clades, encapsulated and non-encapsulated. Genomic correlation of the distinct differences between the two clades is still unclear. Here, we report an annotated draft reference genome of non-encapsulated Trichinella, T. pseudospiralis, and perform comparative multi-omics analyses with encapsulated T. spiralis. Genome and methylome analyses indicate that, during Trichinella evolution, the two clades of Trichinella exhibit differential expansion and methylation of parasitism-related multi-copy gene families, especially for the DNase II members of the phospholipase D superfamily and Glutathione S-transferases. Further, methylome and transcriptome analyses revealed divergent key excretory/secretory (E/S) genes between the two clades. Among these key E/S genes, TP12446 is significantly more expressed across three life stages in T. pseudospiralis. Overexpression of TP12446 in the mouse C2C12 skeletal muscle cell line could induce inhibition of myotube formation and differentiation, further indicating its key role in parasitism of T. pseudospiralis. This multi-omics study provides a foundation for further elucidation of the mechanism of nurse cell formation and immunoevasion, as well as the identification of pharmacological and diagnostic targets of trichinellosis.

scholarly journals Molecular basis of differential parasitism between non-encapsulated and encapsulated Trichinella revealed by a high-quality genome assembly

2019 ◽  
Author(s):  
Xiaolei Liu ◽  
Yayan Feng ◽  
Xue Bai ◽  
Xuelin Wang ◽  
Rui Qin ◽  
...  
Keyword(s):  
Reference Genome ◽  
Repetitive Sequences ◽  
Cell Formation ◽  
Dnase Ii ◽  
Genomic Correlation ◽  
Glutathione S Transferases ◽  
Family Expansion ◽  
Epigenomic Regulation ◽  
Secretory Products ◽  
High Quality Genome

AbstractUnderstanding roles of repetitive sequences in genomes of parasites could offer insights into their evolution, speciation, and parasitism. As a unique intracellular nematode, Trichinella consists of two clades, encapsulated and non-encapsulated. Genomic correlation to the distinct differences between the two clades is still unclear. Here we report an annotated draft reference genome of non-encapsulated Trichinella, T. pseudospiralis, and performed comparative analyses with encapsulated T. spiralis. Genome analysis revealed that, during Trichinella evolution, repetitive sequence insertions played an important role in gene family expansion in synergy with DNA methylation, especially for the DNase II members of the phospholipase D superfamily and Glutathione S-transferases. We further identify the genomic and epigenomic regulation of excretory/secretory products in relation to differences in parasitism, pathology and immunology between the two clades Trichinella. The present study provided a foundation for further elucidation of mechanism of nurse cell formation and immunoevasion as well as identification of phamarcological and diagnostic targets of trichinellosis.

scholarly journals Improved Understanding of the Role of Gene and Genome Duplications in Chordate Evolution With New Genome and Transcriptome Sequences

2021 ◽  
Vol 9 ◽  
Author(s):  
Madeleine E. Aase-Remedios ◽  
David E. K. Ferrier
Keyword(s):  
Chromosomal Rearrangements ◽  
Expression Patterns ◽  
Gene Families ◽  
Evolutionary Transitions ◽  
Whole Genome Duplications ◽  
Chordate Evolution ◽  
Genome Duplications ◽  
The Many ◽  
Genome Assemblies ◽  
The Impact

Comparative approaches to understanding chordate genomes have uncovered a significant role for gene duplications, including whole genome duplications (WGDs), giving rise to and expanding gene families. In developmental biology, gene families created and expanded by both tandem and WGDs are paramount. These genes, often involved in transcription and signalling, are candidates for underpinning major evolutionary transitions because they are particularly prone to retention and subfunctionalisation, neofunctionalisation, or specialisation following duplication. Under the subfunctionalisation model, duplication lays the foundation for the diversification of paralogues, especially in the context of gene regulation. Tandemly duplicated paralogues reside in the same regulatory environment, which may constrain them and result in a gene cluster with closely linked but subtly different expression patterns and functions. Ohnologues (WGD paralogues) often diversify by partitioning their expression domains between retained paralogues, amidst the many changes in the genome during rediploidisation, including chromosomal rearrangements and extensive gene losses. The patterns of these retentions and losses are still not fully understood, nor is the full extent of the impact of gene duplication on chordate evolution. The growing number of sequencing projects, genomic resources, transcriptomics, and improvements to genome assemblies for diverse chordates from non-model and under-sampled lineages like the coelacanth, as well as key lineages, such as amphioxus and lamprey, has allowed more informative comparisons within developmental gene families as well as revealing the extent of conserved synteny across whole genomes. This influx of data provides the tools necessary for phylogenetically informed comparative genomics, which will bring us closer to understanding the evolution of chordate body plan diversity and the changes underpinning the origin and diversification of vertebrates.

scholarly journals Network-based microsynteny analysis identifies major differences and genomic outliers in mammalian and angiosperm genomes

2019 ◽  
Vol 116 (6) ◽  
pp. 2165-2174 ◽  
Author(s):  
Tao Zhao ◽  
M. Eric Schranz
Keyword(s):  
Gene Families ◽  
Single Copy ◽  
Specific Gene ◽  
Phylogenetic Groups ◽  
History Of ◽  
Mammalian Genomes ◽  
Syntenic Conservation ◽  
Genome Assemblies ◽  
Lineage Specific Gene ◽  
Relative Gene

A comprehensive analysis of relative gene order, or microsynteny, can provide valuable information for understanding the evolutionary history of genes and genomes, and ultimately traits and species, across broad phylogenetic groups and divergence times. We have used our network-based phylogenomic synteny analysis pipeline to first analyze the overall patterns and major differences between 87 mammalian and 107 angiosperm genomes. These two important groups have both evolved and radiated over the last ∼170 MYR. Secondly, we identified the genomic outliers or “rebel genes” within each clade. We theorize that rebel genes potentially have influenced trait and lineage evolution. Microsynteny networks use genes as nodes and syntenic relationships between genes as edges. Networks were decomposed into clusters using the Infomap algorithm, followed by phylogenomic copy-number profiling of each cluster. The differences in syntenic properties of all annotated gene families, including BUSCO genes, between the two clades are striking: most genes are single copy and syntenic across mammalian genomes, whereas most genes are multicopy and/or have lineage-specific distributions for angiosperms. We propose microsynteny scores as an alternative and complementary metric to BUSCO for assessing genome assemblies. We further found that the rebel genes are different between the two groups: lineage-specific gene transpositions are unusual in mammals, whereas single-copy highly syntenic genes are rare for flowering plants. We illustrate several examples of mammalian transpositions, such as brain-development genes in primates, and syntenic conservation across angiosperms, such as single-copy genes related to photosynthesis. Future experimental work can test if these are indeed rebels with a cause.

Laboulbeniomycetes: Intimate Fungal Associates of Arthropods

2021 ◽  
Vol 66 (1) ◽  
pp. 257-276 ◽  
Author(s):  
Danny Haelewaters ◽  
Meredith Blackwell ◽  
Donald H. Pfister
Keyword(s):  
Population Biology ◽  
Life Histories ◽  
Invasion Biology ◽  
Species Discovery ◽  
Phylogenetic Studies ◽  
Intimate Association ◽  
Red Algal ◽  
Molecular Phylogenetic ◽  
Parasitic Worms ◽  
Host Parasite

Arthropod–fungus interactions involving the Laboulbeniomycetes have been pondered for several hundred years. Early studies of Laboulbeniomycetes faced several uncertainties. Were they parasitic worms, red algal relatives, or fungi? If they were fungi, to which group did they belong? What was the nature of their interactions with their arthropod hosts? The historical misperceptions resulted from the extraordinary morphological features of these oddly constructed ectoparasitic fungi. More recently, molecular phylogenetic studies, in combination with a better understanding of life histories, have clearly placed these fungi among filamentous Ascomycota (subphylum Pezizomycotina). Species discovery and research on the classification of the group continue today as arthropods, and especially insects, are routinely collected and examined for the presence of Laboulbeniomycetes. Newly armed with molecular methods, mycologists are poisedto use Laboulbeniomycetes–insect associations as models for the study of a variety of basic evolutionary and ecological questions involving host–parasite relationships, modes of nutrient intake, population biology, host specificity, biological control, and invasion biology. Collaboration between mycologists and entomologists is essential to successfully advance knowledge of Laboulbeniomycetes and their intimate association with their hosts.

scholarly journals Structural rearrangements drive extensive genome divergence between symbiotic and free-living Symbiodinium

2019 ◽  
Author(s):  
Raúl A. González-Pech ◽  
Timothy G. Stephens ◽  
Yibi Chen ◽  
Amin R. Mohamed ◽  
Yuanyuan Cheng ◽  
...  
Keyword(s):  
Genome Size ◽  
Molecular Mechanisms ◽  
De Novo ◽  
Sequence Divergence ◽  
Gene Families ◽  
Homologous Gene ◽  
Structural Rearrangements ◽  
Free Living ◽  
Symbiotic Dinoflagellates ◽  
Genome Assemblies

AbstractSymbiodiniaceae are predominantly symbiotic dinoflagellates critical to corals and other reef organisms. Symbiodinium is a basal symbiodiniacean lineage and includes symbiotic and free-living taxa. However, the molecular mechanisms underpinning these distinct lifestyles remain little known. Here, we present high-quality de novo genome assemblies for the symbiotic Symbiodinium tridacnidorum CCMP2592 (genome size 1.3 Gbp) and the free-living Symbiodinium natans CCMP2548 (genome size 0.74 Gbp). These genomes display extensive sequence divergence, sharing only ~1.5% conserved regions (≥90% identity). We predicted 45,474 and 35,270 genes for S. tridacnidorum and S. natans, respectively; of the 58,541 homologous gene families, 28.5% are common to both genomes. We recovered a greater extent of gene duplication and higher abundance of repeats, transposable elements and pseudogenes in the genome of S. tridacnidorum than in that of S. natans. These findings demonstrate that genome structural rearrangements are pertinent to distinct lifestyles in Symbiodinium, and may contribute to the vast genetic diversity within the genus, and more broadly in Symbiodiniaceae. Moreover, the results from our whole-genome comparisons against a free-living outgroup support the notion that the symbiotic lifestyle is a derived trait in, and that the free-living lifestyle is ancestral to, Symbiodinium.

scholarly journals Gene Duplication and Gain in the Trematode Atriophallophorus Winterbourni Contributes to Adaptation to Parasitism

2021 ◽  
Author(s):  
Natalia Zajac ◽  
Stefan Zoller ◽  
Katri Seppälä ◽  
David Moi ◽  
Christophe Dessimoz ◽  
...  
Keyword(s):  
De Novo ◽  
Genomic Analysis ◽  
Enrichment Analysis ◽  
Gene Families ◽  
Comparative Genomic ◽  
Genomic Changes ◽  
Go Enrichment ◽  
Duplication Events ◽  
Parasitic Lifestyle ◽  
Host Parasite

Abstract Gene duplications and novel genes have been shown to play a major role in helminth adaptation to a parasitic lifestyle because they provide the novelty necessary for adaptation to a changing environment, such as living in multiple hosts. Here we present the de novo sequenced and annotated genome of the parasitic trematode Atriophallophorus winterbourni and its comparative genomic analysis to other major parasitic trematodes. First, we reconstructed the species phylogeny, and dated the split of A. winterbourni from the Opisthorchiata suborder to approximately 237.4 MYA (± 120.4 MY). We then addressed the question of which expanded gene families and gained genes are potentially involved in adaptation to parasitism. To do this, we used Hierarchical Orthologous Groups to reconstruct three ancestral genomes on the phylogeny leading to A. winterbourni and performed a GO enrichment analysis of the gene composition of each ancestral genome, allowing us to characterize the subsequent genomic changes. Out of the 11,499 genes in the A. winterbourni genome, as much as 24% have arisen through duplication events since the speciation of A. winterbourni from the Opisthorchiata, and as much as 31.9% appear to be novel, i.e. newly acquired. We found 13 gene families in A. winterbourni to have had more than 10 genes arising through these recent duplications; all of which have functions potentially relating to host behavioural manipulation, host tissue penetration, and hiding from host immunity through antigen presentation. We identified several families with genes evolving under positive selection. Our results provide a valuable resource for future studies on the genomic basis of adaptation to parasitism and point to specific candidate genes putatively involved in antagonistic host-parasite adaptation.

scholarly journals Reference Genome for the Highly Transformable Setaria viridis ME034V

2020 ◽  
Vol 10 (10) ◽  
pp. 3467-3478 ◽  
Author(s):  
Peter M. Thielen ◽  
Amanda L. Pendleton ◽  
Robert A. Player ◽  
Kenneth V. Bowden ◽  
Thomas J. Lawton ◽  
...  
Keyword(s):  
De Novo ◽  
Gene Families ◽  
Model Organisms ◽  
Phylogenomic Analysis ◽  
Setaria Viridis ◽  
Sequencing Technology ◽  
Protein Coding ◽  
Genotype Frequencies ◽  
Green Foxtail ◽  
Genome Assemblies

Setaria viridis (green foxtail) is an important model system for improving cereal crops due to its diploid genome, ease of cultivation, and use of C4 photosynthesis. The S. viridis accession ME034V is exceptionally transformable, but the lack of a sequenced genome for this accession has limited its utility. We present a 397 Mb highly contiguous de novo assembly of ME034V using ultra-long nanopore sequencing technology (read N50 = 41kb). We estimate that this genome is largely complete based on our updated k-mer based genome size estimate of 401 Mb for S. viridis. Genome annotation identified 37,908 protein-coding genes and >300k repetitive elements comprising 46% of the genome. We compared the ME034V assembly with two other previously sequenced Setaria genomes as well as to a diversity panel of 235 S. viridis accessions. We found the genome assemblies to be largely syntenic, but numerous unique polymorphic structural variants were discovered. Several ME034V deletions may be associated with recent retrotransposition of copia and gypsy LTR repeat families, as evidenced by their low genotype frequencies in the sampled population. Lastly, we performed a phylogenomic analysis to identify gene families that have expanded in Setaria, including those involved in specialized metabolism and plant defense response. The high continuity of the ME034V genome assembly validates the utility of ultra-long DNA sequencing to improve genetic resources for emerging model organisms. Structural variation present in Setaria illustrates the importance of obtaining the proper genome reference for genetic experiments. Thus, we anticipate that the ME034V genome will be of significant utility for the Setaria research community.

scholarly journals The Genome of the Great Gerbil Reveals Species-Specific Duplication of an MHCII Gene

2020 ◽  
Vol 12 (2) ◽  
pp. 3832-3849 ◽  
Author(s):  
Pernille Nilsson ◽  
Monica H Solbakken ◽  
Boris V Schmid ◽  
Russell J S Orr ◽  
Ruichen Lv ◽  
...  
Keyword(s):  
Gene Families ◽  
Meriones Unguiculatus ◽  
Comparative Genomic ◽  
Great Gerbil ◽  
Main Host ◽  
Rhombomys Opimus ◽  
Vector Borne ◽  
Species Specific ◽  
Close Relatives ◽  
Genome Assemblies

Abstract The great gerbil (Rhombomys opimus) is a social rodent living in permanent, complex burrow systems distributed throughout Central Asia, where it serves as the main host of several important vector-borne infectious pathogens including the well-known plague bacterium (Yersinia pestis). Here, we present a continuous annotated genome assembly of the great gerbil, covering over 96% of the estimated 2.47-Gb genome. Taking advantage of the recent genome assemblies of the sand rat (Psammomys obesus) and the Mongolian gerbil (Meriones unguiculatus), comparative immunogenomic analyses reveal shared gene losses within TLR gene families (i.e., TLR8, TLR10, and the entire TLR11-subfamily) for Gerbillinae, accompanied with signs of diversifying selection of TLR7 and TLR9. Most notably, we find a great gerbil-specific duplication of the MHCII DRB locus. In silico analyses suggest that the duplicated gene provides high peptide binding affinity for Yersiniae epitopes as well as Leishmania and Leptospira epitopes, putatively leading to increased capability to withstand infections by these pathogens. Our study demonstrates the power of whole-genome sequencing combined with comparative genomic analyses to gain deeper insight into the immunogenomic landscape of the great gerbil and its close relatives.

scholarly journals Comparison of 15 dinoflagellate genomes reveals extensive sequence and structural divergence in family Symbiodiniaceae and genus Symbiodinium

BMC Biology ◽  
2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Raúl A. González-Pech ◽  
Timothy G. Stephens ◽  
Yibi Chen ◽  
Amin R. Mohamed ◽  
Yuanyuan Cheng ◽  
...  
Keyword(s):  
De Novo ◽  
Gene Families ◽  
Specific Gene ◽  
Free Living ◽  
Microbial Eukaryotes ◽  
The Family ◽  
Structural Divergence ◽  
Genome Features ◽  
Genome Divergence ◽  
Genome Assemblies

Abstract Background Dinoflagellates in the family Symbiodiniaceae are important photosynthetic symbionts in cnidarians (such as corals) and other coral reef organisms. Breakdown of the coral-dinoflagellate symbiosis due to environmental stress (i.e. coral bleaching) can lead to coral death and the potential collapse of reef ecosystems. However, evolution of Symbiodiniaceae genomes, and its implications for the coral, is little understood. Genome sequences of Symbiodiniaceae remain scarce due in part to their large genome sizes (1–5 Gbp) and idiosyncratic genome features. Results Here, we present de novo genome assemblies of seven members of the genus Symbiodinium, of which two are free-living, one is an opportunistic symbiont, and the remainder are mutualistic symbionts. Integrating other available data, we compare 15 dinoflagellate genomes revealing high sequence and structural divergence. Divergence among some Symbiodinium isolates is comparable to that among distinct genera of Symbiodiniaceae. We also recovered hundreds of gene families specific to each lineage, many of which encode unknown functions. An in-depth comparison between the genomes of the symbiotic Symbiodinium tridacnidorum (isolated from a coral) and the free-living Symbiodinium natans reveals a greater prevalence of transposable elements, genetic duplication, structural rearrangements, and pseudogenisation in the symbiotic species. Conclusions Our results underscore the potential impact of lifestyle on lineage-specific gene-function innovation, genome divergence, and the diversification of Symbiodinium and Symbiodiniaceae. The divergent features we report, and their putative causes, may also apply to other microbial eukaryotes that have undergone symbiotic phases in their evolutionary history.

Complexity of the major surface protease (msp) gene organization inLeishmania (Viannia) braziliensis: evolutionary and functional implications

Parasitology ◽  
2005 ◽  
Vol 131 (2) ◽  
pp. 207-214 ◽  
Author(s):  
K. VICTOIR ◽  
J. AREVALO ◽  
S. DE DONCKER ◽  
D. C. BARKER ◽  
T. LAURENT ◽  
...  
Keyword(s):  
Gene Families ◽  
Adaptive Strategy ◽  
Gene Organization ◽  
Point Of View ◽  
T Cell Epitopes ◽  
Conserved Sequence ◽  
Functional Implications ◽  
Surface Domains ◽  
Major Surface ◽  
Host Parasite

The major surface protease (msp orgp63) ofLeishmaniaplays a major role in the host–parasite interaction. We analysed here the structure of the msp gene locus inLeishmania (Viannia) braziliensisand compared it to results obtained in other species. Physical mapping of cosmid contigs revealed a minimum of 37 genes per haploid genome and at least 8 different msp gene families. Within the same organism, these genes showed a nucleotide sequence varying in certain stretches from 3 to 34%, and a mosaic structure. From an evolutionary point of view, major differences were observed between subgeneraVianniaandLeishmania, both in terms of msp gene number and sequence. Within subgenusViannia, phenetic analysis revealed three clusters in which sequence variants ofL. (Viannia) braziliensisandL. (Viannia) guyanensiswere interspersed. Functional implications of our results were explored from predictedL. (Viannia) braziliensisprotein sequences: regions encoding the msp catalytic site showed a conserved sequence, while regions encoding surface domains possibly involved in the host–parasite interaction (macrophage adhesion sites and immunodominant B-cell and T-cell epitopes) were variable. We speculate that this would be an adaptive strategy of the parasite.

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