scholarly journals The genome of the plague-resistant great gerbil reveals species-specific duplication of an MHCII gene

2018 ◽  
Author(s):  
Pernille Nilsson ◽  
Monica H. Solbakken ◽  
Boris V. Schmid ◽  
Russell J. S. Orr ◽  
Ruichen Lv ◽  
...  

AbstractThe 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 diseases and is defined as a key reservoir species for plague (Yersinia pestis). Studies from the wild have shown that the great gerbil is largely resistant to plague but the genetic basis for resistance is yet to be determined. Here, we present a highly contiguous annotated genome assembly of great gerbil, covering over 96 % of the estimated 2.47 Gb genome. Comparative genomic analyses focusing on the immune gene repertoire, reveal shared gene losses within TLR gene families (i.e. TLR8, TLR10 and all members of TLR11-subfamily) for the Gerbillinae lineage, 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. The great gerbil genome provides new insights into the genomic landscape that confers immunological resistance towards plague. The high affinity for Yersinia epitopes could be key in our understanding of the high resistance in great gerbils, putatively conferring a faster initiation of the adaptive immune response leading to survival of the infection. Our study demonstrates the power of studying zoonosis in natural hosts through the generation of a genome resource for further comparative and experimental work on plague survival and evolution of host-pathogen interactions.


2020 ◽  
Vol 12 (2) ◽  
pp. 3832-3849 ◽  
Author(s):  
Pernille Nilsson ◽  
Monica H Solbakken ◽  
Boris V Schmid ◽  
Russell J S Orr ◽  
Ruichen Lv ◽  
...  

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.



2019 ◽  
Author(s):  
Mosè Manni ◽  
Felipe A. Simao ◽  
Hugh M. Robertson ◽  
Marco A. Gabaglio ◽  
Robert M. Waterhouse ◽  
...  

AbstractThe dipluran two-pronged bristletail Campodea augens is a blind ancestrally wingless hexapod with the remarkable capacity to regenerate lost body appendages such as its long antennae. As sister group to Insecta (sensu stricto), Diplura are key to understanding the early evolution of hexapods and the origin and evolution of insects. Here we report the 1.2-Gbp draft genome of C. augens and results from comparative genomic analyses with other arthropods. In C. augens we uncovered the largest chemosensory gene repertoire of ionotropic receptors in the animal kingdom, a massive expansion which might compensate for the loss of vision. We found a paucity of photoreceptor genes mirroring at the genomic level the secondary loss of an ancestral external photoreceptor organ. Expansions of detoxification and carbohydrate metabolism gene families might reflect adaptations for foraging behaviour, and duplicated apoptotic genes might underlie its high regenerative potential.The C. augens genome represents one of the key references for studying the emergence of genomic innovations in insects, the most diverse animal group, and opens up novel opportunities to study the under-explored biology of diplurans.



2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Lisong Hu ◽  
Zhongping Xu ◽  
Maojun Wang ◽  
Rui Fan ◽  
Daojun Yuan ◽  
...  

Abstract Black pepper (Piper nigrum), dubbed the ‘King of Spices’ and ‘Black Gold’, is one of the most widely used spices. Here, we present its reference genome assembly by integrating PacBio, 10x Chromium, BioNano DLS optical mapping, and Hi-C mapping technologies. The 761.2 Mb sequences (45 scaffolds with an N50 of 29.8 Mb) are assembled into 26 pseudochromosomes. A phylogenomic analysis of representative plant genomes places magnoliids as sister to the monocots-eudicots clade and indicates that black pepper has diverged from the shared Laurales-Magnoliales lineage approximately 180 million years ago. Comparative genomic analyses reveal specific gene expansions in the glycosyltransferase, cytochrome P450, shikimate hydroxycinnamoyl transferase, lysine decarboxylase, and acyltransferase gene families. Comparative transcriptomic analyses disclose berry-specific upregulated expression in representative genes in each of these gene families. These data provide an evolutionary perspective and shed light on the metabolic processes relevant to the molecular basis of species-specific piperine biosynthesis.



Genes ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 624 ◽  
Author(s):  
Rachele Antonacci ◽  
Serafina Massari ◽  
Giovanna Linguiti ◽  
Anna Caputi Jambrenghi ◽  
Francesco Giannico ◽  
...  

T lymphocytes are the principal actors of vertebrates’ cell-mediated immunity. Like B cells, they can recognize an unlimited number of foreign molecules through their antigen-specific heterodimer receptors (TRs), which consist of αβ or γδ chains. The diversity of the TRs is mainly due to the unique organization of the genes encoding the α, β, γ, and δ chains. For each chain, multi-gene families are arranged in a TR locus, and their expression is guaranteed by the somatic recombination process. A great plasticity of the gene organization within the TR loci exists among species. Marked structural differences affect the TR γ (TRG) locus. The recent sequencing of multiple whole genome provides an opportunity to examine the TR gene repertoire in a systematic and consistent fashion. In this review, we report the most recent findings on the genomic organization of TRG loci in mammalian species in order to show differences and similarities. The comparison revealed remarkable diversification of both the genomic organization and gene repertoire across species, but also unexpected evolutionary conservation, which highlights the important role of the T cells in the immune response.



2020 ◽  
Vol 7 (1) ◽  
Author(s):  
Li Huang ◽  
Yazhen Ma ◽  
Jiebei Jiang ◽  
Ting Li ◽  
Wenjie Yang ◽  
...  

AbstractLobularia maritima (L.) Desv. is an ornamental plant cultivated across the world. It belongs to the family Brassicaceae and can tolerate dry, poor and contaminated habitats. Here, we present a chromosome-scale, high-quality genome assembly of L. maritima based on integrated approaches combining Illumina short reads and Hi–C chromosome conformation data. The genome was assembled into 12 pseudochromosomes with a 197.70 Mb length, and it includes 25,813 protein-coding genes. Approximately 41.94% of the genome consists of repetitive sequences, with abundant long terminal repeat transposable elements. Comparative genomic analysis confirmed that L. maritima underwent a species-specific whole-genome duplication (WGD) event ~22.99 million years ago. We identified ~1900 species-specific genes, 25 expanded gene families, and 50 positively selected genes in L. maritima. Functional annotations of these genes indicated that they are mainly related to stress tolerance. These results provide new insights into the stress tolerance of L. maritima, and this genomic resource will be valuable for further genetic improvement of this important ornamental plant.



2019 ◽  
Vol 12 (1) ◽  
pp. 3534-3549
Author(s):  
Mosè Manni ◽  
Felipe A Simao ◽  
Hugh M Robertson ◽  
Marco A Gabaglio ◽  
Robert M Waterhouse ◽  
...  

Abstract The dipluran two-pronged bristletail Campodea augens is a blind ancestrally wingless hexapod with the remarkable capacity to regenerate lost body appendages such as its long antennae. As sister group to Insecta (sensu stricto), Diplura are key to understanding the early evolution of hexapods and the origin and evolution of insects. Here we report the 1.2-Gb draft genome of C. augens and results from comparative genomic analyses with other arthropods. In C. augens, we uncovered the largest chemosensory gene repertoire of ionotropic receptors in the animal kingdom, a massive expansion that might compensate for the loss of vision. We found a paucity of photoreceptor genes mirroring at the genomic level the secondary loss of an ancestral external photoreceptor organ. Expansions of detoxification and carbohydrate metabolism gene families might reflect adaptations for foraging behavior, and duplicated apoptotic genes might underlie its high regenerative potential. The C. augens genome represents one of the key references for studying the emergence of genomic innovations in insects, the most diverse animal group, and opens up novel opportunities to study the under-explored biology of diplurans.



Viruses ◽  
2022 ◽  
Vol 14 (1) ◽  
pp. 128
Author(s):  
Sara Becker ◽  
Annette Fink ◽  
Jürgen Podlech ◽  
Matthias J. Reddehase ◽  
Niels A. Lemmermann

Cytomegaloviruses (CMVs) are host species-specific and have adapted to their respective mammalian hosts during co-evolution. Host-adaptation is reflected by “private genes” that have specialized in mediating virus-host interplay and have no sequence homologs in other CMV species, although biological convergence has led to analogous protein functions. They are mostly organized in gene families evolved by gene duplications and subsequent mutations. The host immune response to infection, both the innate and the adaptive immune response, is a driver of viral evolution, resulting in the acquisition of viral immune evasion proteins encoded by private gene families. As the analysis of the medically relevant human cytomegalovirus by clinical investigation in the infected human host cannot make use of designed virus and host mutagenesis, the mouse model based on murine cytomegalovirus (mCMV) has become a versatile animal model to study basic principles of in vivo virus-host interplay. Focusing on the immune evasion of the adaptive immune response by CD8+ T cells, we review here what is known about proteins of two private gene families of mCMV, the m02 and the m145 families, specifically the role of m04, m06, and m152 in viral antigen presentation during acute and latent infection.



2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Yunsheng Wang

AbstractLoquat (Eriobotrya japonica) is a popular fruit and medicinal plant. Here, a high-quality draft genome of the E. japonica ‘Big Five-pointed Star’ cultivar that covers ~98% (733.32 Mb) of the estimated genome size (749.25 Mb) and contains a total of 45,492 protein-coding genes is reported. Comparative genomic analysis suggests that the loquat genome has evolved a unique genetic mechanism of chromosome repair. Resequencing data from 52 loquat cultivars, including 16 white-fleshed and 36 yellow-fleshed variants, were analyzed, and the flower, leaf, and root metabolomes of ‘Big Five-pointed Star’ were determined using a UPLC-ESI-MS/M system. A genome-wide association study identified several candidate genes associated with flesh color in E. japonica, linking these phenotypes to sugar metabolism. A total of 577 metabolites, including 98 phenolic acids, 95 flavonoids, and 28 terpenoids, were found, and 191 metabolites, including 46 phenolic acids, 33 flavonoids, and 7 terpenoids, showed no differences in concentration among the leaves, roots, and flowers. Candidate genes related to the biosynthesis of various medicinal ingredients, such as phenolics, flavonoids, terpenoids, and polysaccharides, were identified. Some of these genes were confirmed to be members of expanding gene families, suggesting that the high concentrations of beneficial metabolites in loquat may be associated with the number of biosynthetic genes in this plant. In summary, this study provides fundamental molecular insights into the nutritional and medical properties of E. japonica.



2009 ◽  
Vol 57 (4) ◽  
pp. 185 ◽  
Author(s):  
Emily S. W. Wong ◽  
Anthony T. Papenfuss ◽  
Robert D. Miller ◽  
Katherine Belov

The sequencing of the platypus genome has spurred investigations into the characterisation of the monotreme immune response. As the most divergent of extant mammals, the characterisation of the monotreme immune repertoire allows us to trace the evolutionary history of immunity in mammals and provide insights into the immune gene complement of ancestral mammals. The immune system of monotremes has remained largely uncharacterised due to the lack of specific immunological reagents and limited access to animals for experimentation. Early immunological studies focussed on the anatomy and physiology of the lymphoid system in the platypus. More recent molecular studies have focussed on characterisation of individual immunoglobulin, T-cell receptor and MHC genes in both the platypus and short-beaked echidna. Here, we review the published literature on the monotreme immune gene repertoire and provide new data generated from genome analysis on cytokines, Fc receptors and immunoglobulins. We present an overview of key gene families responsible for innate and adaptive immunity including the cathelicidins, defensins, T-cell receptors and the major histocompatibility complex (MHC) Class I and Class II antigens. We comment on the usefulness of these sequences for future studies into immunity, health and disease in monotremes.



2013 ◽  
Vol 280 (1750) ◽  
pp. 20122113 ◽  
Author(s):  
Andreas Vilcinskas ◽  
Krishnendu Mukherjee ◽  
Heiko Vogel

The harlequin ladybird beetle Harmonia axyridis has emerged as a model species in invasion biology because of its strong resistance against pathogens and remarkable capacity to outcompete native ladybirds. The invasive success of the species may reflect its well-adapted immune system, a hypothesis we tested by analysing the transcriptome and characterizing the immune gene repertoire of untreated beetles and those challenged with bacteria and fungi. We found that most H. axyridis immunity-related genes were similar in diversity to their counterparts in the reference beetle Tribolium castaneum , but there was an unprecedented expansion among genes encoding antimicrobial peptides and proteins (AMPs). We identified more than 50 putative AMPs belonging to seven different gene families, and many of the corresponding genes were shown by quantitative real-time RT–PCR to be induced in the immune-stimulated beetles. AMPs with the highest induction ratio in the challenged beetles were shown to demonstrate broad and potent activity against Gram-negative bacteria and entomopathogenic fungi. The invasive success of H. axyridis can therefore be attributed at least in part to the greater efficiency of its immune system, particularly the expansion of AMP gene families and their induction in response to pathogens.



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