Alteration in the Culex pipiens transcriptome reveals diverse mechanisms of the mosquito immune system implicated upon Rift Valley fever phlebovirus exposure

Rift Valley fever phlebovirus (RVFV) causes an emerging zoonotic disease and is mainly transmitted by Culex and Aedes mosquitoes. While Aedes aegypti-dengue virus (DENV) is the most studied model, less is known about the genes involved in infection-responses in other mosquito-arboviruses pairing. The main objective was to investigate the molecular responses of Cx. pipiens to RVFV exposure focusing mainly on genes implicated in innate immune responses. Mosquitoes were fed with blood spiked with RVFV. The fully-engorged females were pooled at 3 different time points: 2 hours post-exposure (hpe), 3- and 14-days post-exposure (dpe). Pools of mosquitoes fed with non-infected blood were also collected for comparisons. Total RNA from each mosquito pool was subjected to RNA-seq analysis and a de novo transcriptome was constructed. A total of 451 differentially expressed genes (DEG) were identified. Most of the transcriptomic alterations were found at an early infection stage after RVFV exposure. Forty-eight DEG related to immune infection-response were characterized. Most of them were related with the RNAi system, Toll and IMD pathways, ubiquitination pathway and apoptosis. Our findings provide for the first time a comprehensive view on Cx. pipiens-RVFV interactions at the molecular level. The early depletion of RNAi pathway genes at the onset of the RVFV infection would allow viral replication in mosquitoes. While genes from the Toll and IMD immune pathways were altered in response to RVFV none of the DEG were related to the JAK/STAT pathway. The fact that most of the DEG involved in the Ubiquitin-proteasome pathway (UPP) or apoptosis were found at an early stage of infection would suggest that apoptosis plays a regulatory role in infected Cx. pipiens midguts. This study provides a number of target genes that could be used to identify new molecular targets for vector control.info:eu-repo/semantics/publishedVersio

European sea bass brain DLB-1 cell line is susceptible to nodavirus: A transcriptomic study

Viral diseases are responsible for high rates of mortality and subsequent economic losses in modern aquaculture. The nervous necrosis virus (NNV) produces viral encephalopathy and retinopathy (VER), which affects the fish central nervous system. It is considered one of the most serious viral diseases in marine aquaculture, the European sea bass (Dicentrarchus labrax) being amongst the most susceptible. We have evaluated the European sea bass brain derived cell line (DLB-1) susceptibility to NNV genotypes and evaluated its transcriptomic profile. DLB-1 cells supported NNV gene transcription and replication since strains belonging to the four NNV genotypes produce cytopathic effects. Afterwards, DLB-1 cells were infected with an RGNNV strain, the one which showed the highest replication, for 12 and 72 h and an RNA-seq analysis was performed to identify potential genes involved in the host-NNV interactions. Differential expression analysis showed the up-regulation of many genes related to immunity, heat-shock proteins or apoptosis but not to proteasome or autophagy processes. These data suggest that the immune response, mainly the interferon (IFN) pathway, is not powerful enough to abrogate the infection, and cells finally suffer stress and die by apoptosis liberating infective particles. GO enrichment also revealed, for the first time, the down-regulation of terms related to brain/neuron biology indicating molecular mechanisms causing the pathogenic effect of NNV. This study opens the way to understand key elements in sea bass brain and NNV interactions.Versión del edito

De novo transcriptome sequencing and gene co-expression reveal a genomic basis for drought sensitivity and evidence of a rapid local adaptation on Atlas cedar (Cedrus atlantica)

IntroductionUnderstanding the adaptive capacity to current climate change of drought-sensitive tree species is mandatory, given their limited prospect of migration and adaptation as long-lived, sessile organisms. Knowledge about the molecular and eco-physiological mechanisms that control drought resilience is thus key, since water shortage appears as one of the main abiotic factors threatening forests ecosystems. However, our current background is scarce, especially in conifers, due to their huge and complex genomes.MethodsHere we investigated the eco-physiological and transcriptomic basis of drought response of the climate change-threatened conifer Cedrus atlantica. We studied C. atlantica seedlings from two locations with contrasting drought conditions to investigate a local adaptation. Seedlings were subjected to experimental drought conditions, and were monitored at immediate (24 hours) and extended (20 days) times. In addition, post-drought recovery was investigated, depicting two contrasting responses in both locations (drought resilient and non-resilient). Single nucleotide polymorphisms (SNPs) were also studied to characterize the genomic basis of drought resilience and investigate a rapid local adaptation of C. atlantica.ResultsDe novo transcriptome assembly was performed for the first time in this species, providing differences in gene expression between the immediate and extended treatments, as well as among the post-drought recovery phenotypes. Weighted gene co-expression network analysis showed a regulation of stomatal closing and photosynthetic activity during the immediate drought, consistent with an isohydric dynamic. During the extended drought, growth and flavonoid biosynthesis inhibition mechanisms prevailed, probably to increase root-to-shoot ratio and to limit the energy-intensive biosynthesis of secondary metabolites. Drought sensitive individuals failed in metabolism and photosynthesis regulation under drought stress, and in limiting secondary metabolite production. Moreover, genomic differences (SNPs) were found between drought resilient and sensitive seedlings, and between the two studied locations, which were mostly related to transposable elements.DiscussionThis work provides novel insights into the transcriptomic basis of drought response of C. atlantica, a set of candidate genes mechanistically involved in its drought sensitivity and evidence of a rapid local adaptation. Our results may help guide conservation programs for this threatened conifer, contribute to advance drought-resilience research and shed light on trees’ adaptive potential to current climate change

Transposons played a major role in the diversification between the closely related almond and peach genomes: Results from the almond genome sequence

We sequenced the genome of the highly heterozygous almond Prunus dulcis cv. Texas combining short and long‐read sequencing. We obtained a genome assembly totaling 227.6 Mb of the estimated 238 Mb almond genome size, of which 91% is anchored to eight pseudomolecules corresponding to its haploid chromosome complement, and annotated 27,969 protein‐coding genes and 6,747 non‐coding transcripts. By phylogenomic comparison with the genomes of 16 additional close and distant species we estimated that almond and peach (P. persica) diverged around 5.88 Mya. These two genomes are highly syntenic and show a high degree of sequence conservation (20 nucleotide substitutions/kb). However, they also exhibit a high number of presence/absence variants, many attributable to the movement of transposable elements (TEs). TEs have generated an important number of presence/absence variants between almond and peach, and we show that the recent history of TE movement seems markedly different between them. TEs may also be at the origin of important phenotypic differences between both species, and in particular, for the sweet kernel phenotype, a key agronomic and domestication character for almond. Here we show that in sweet almond cultivars, highly methylated TE insertions surround a gene involved in the biosynthesis of amygdalin, whose reduced expression has been correlated with the sweet almond phenotype. Altogether, our results suggest a key role of TEs in the recent history and diversification of almond and its close relative peach.info:eu-repo/semantics/publishedVersio

A chromosome-level genome assembly enables the identification of the follicule stimulating hormone receptor as the master sex-determining gene in the flatfish Solea senegalensis

Sex determination (SD) shows huge variation among fish and a high evolutionary rate, as illustrated by the Pleuronectiformes (flatfishes). This order is characterized by its adaptation to demersal life, compact genomes and diversity of SD mechanisms. Here, we assembled the Solea senegalensis genome, a flatfish of great commercial value, into 82 contigs (614 Mb) combining long- and short-read sequencing, which were next scaffolded using a highly dense genetic map (28,838 markers, 21 linkage groups), representing 98.9% of the assembly. Further, we established the correspondence between the assembly and the 21 chromosomes by using BAC-FISH. Whole genome resequencing of six males and six females enabled the identification of 41 single nucleotide polymorphism variants in the follicle stimulating hormone receptor (fshr) consistent with an XX/XY SD system. The observed sex association was validated in a broader independent sample, providing a novel molecular sexing tool. The fshr gene displayed differential expression between male and female gonads from 86 days post-fertilization, when the gonad is still an undifferentiated primordium, concomitant with the activation of amh and cyp19a1a, testis and ovary marker genes, respectively, in males and females. The Y-linked fshr allele, which included 24 nonsynonymous variants and showed a highly divergent 3D protein structure, was overexpressed in males compared to the X-linked allele at all stages of gonadal differentiation. We hypothesize a mechanism hampering the action of the follicle stimulating hormone driving the undifferentiated gonad toward testisEuropean Union's Horizon 2020 research and innovation programme under grant agreement (AQUA-FAANG). Grant Number: 81792. Junta de Andalucía-FEDER Grant. Grant Number: P20-00938. Spanish Ministry of Economy and Competitiveness, FEDER Grants. Grant Numbers: RTI2018-096847-B-C21, RTI2018-096847-B-C22S

Whole genome sequencing of turbot (Scophthalmus maximus; Pleuronectiformes):a fish adapted to demersal life

12 páginas, 5 figuras.-- Antonio Figueras ... et al.-- This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly citedThe turbot is a flatfish (Pleuronectiformes) with increasing commercial value, which has prompted active genomic research aimed at more efficient selection. Here we present the sequence and annotation of the turbot genome, which represents a milestone for both boosting breeding programmes and ascertaining the origin and diversification of flatfish. We compare the turbot genome with model fish genomes to investigate teleost chromosome evolution. We observe a conserved macrosyntenic pattern within Percomorpha and identify large syntenic blocks within the turbot genome related to the teleost genome duplication. We identify gene family expansions and positive selection of genes associated with vision and metabolism of membrane lipids, which suggests adaptation to demersal lifestyle and to cold temperatures, respectively. Our data indicate a quick evolution and diversification of flatfish to adapt to benthic life and provide clues for understanding their controversial origin. Moreover, we investigate the genomic architecture of growth, sex determination and disease resistance, key traits for understanding local adaptation and boosting turbot production, by mapping candidate genes and previously reported quantitative trait loci. The genomic architecture of these productive traits has allowed the identification of candidate genes and enriched pathways that may represent useful information for future marker-assisted selection in turbotThis work was funded by the Spanish Government: projects Consolider Ingenio: Aquagenomics (CSD2007-00002) and Metagenoma de la Península Ibérica (CSD2007-00005), Ministerio de Economía y Competitividad and European Regional Development Funds (AGL2012-35904), and Ministerio de Economía y Competitividad (AGL2014-51773 and AGL2014-57065-R); and Local Government Xunta de Galicia (GRC2014/010). P.P. and D.R. gratefully acknowledge the Spanish Ministerio de Educación for their FPU fellowships (AP2010-2408, AP2012-0254). Funding to pay the Open Access publication charges for this article was provided by the Ministerio de Economía y Competitividad (AGL2014-51773) and Xunta de Galicia (GRC2014/010)Peer reviewe

The European Reference Genome Atlas: piloting a decentralised approach to equitable biodiversity genomics.

ABSTRACT: A global genome database of all of Earth’s species diversity could be a treasure trove of scientific discoveries. However, regardless of the major advances in genome sequencing technologies, only a tiny fraction of species have genomic information available. To contribute to a more complete planetary genomic database, scientists and institutions across the world have united under the Earth BioGenome Project (EBP), which plans to sequence and assemble high-quality reference genomes for all ∼1.5 million recognized eukaryotic species through a stepwise phased approach. As the initiative transitions into Phase II, where 150,000 species are to be sequenced in just four years, worldwide participation in the project will be fundamental to success. As the European node of the EBP, the European Reference Genome Atlas (ERGA) seeks to implement a new decentralised, accessible, equitable and inclusive model for producing high-quality reference genomes, which will inform EBP as it scales. To embark on this mission, ERGA launched a Pilot Project to establish a network across Europe to develop and test the first infrastructure of its kind for the coordinated and distributed reference genome production on 98 European eukaryotic species from sample providers across 33 European countries. Here we outline the process and challenges faced during the development of a pilot infrastructure for the production of reference genome resources, and explore the effectiveness of this approach in terms of high-quality reference genome production, considering also equity and inclusion. The outcomes and lessons learned during this pilot provide a solid foundation for ERGA while offering key learnings to other transnational and national genomic resource projects.info:eu-repo/semantics/publishedVersio

Chromosome-level genome assemblies to rediscover and conserve Catalonia’s biodiversity

Conèixer el genoma de les espècies que ens envolten és crucial per preservar la biodiversitat del territori. Assemblar un genoma consisteix a reconvertir les lectures fragmentades produïdes pels seqüenciadors en una seqüència contigua que representa el genoma complet de l’individu seqüenciat. Abans de l’arribada de les tecnologies de seqüenciació de lectura llarga, la majoria d’assemblatges produïts eren molt fragmentats, cosa que en limitava algunes de les utilitats. La incorporació de les noves tecnologies al camp de l’assemblatge de genomes ha permès una simplificació del procés i una millora de la qualitat dels assemblatges produïts. Els passos per obtenir un genoma de referència són: elaboració de blocs de seqüències consensuades, correcció de la seqüència, reconstrucció de cromosomes i perfeccionament de l’assemblatge. Un assemblatge de referència ens permet fer moltes anàlisis posteriors, com descobrir trets únics d’una espècie, que poden beneficiar les estratègies de conservació.It is very important to have a knowledge of the genomes of the species around us in order to preserve a region’s biodiversity. Assembling a genome involves combining the fragmented reads produced by sequencers into a contiguous sequence that represents the complete genome of the sequenced individual. Before the incorporation of long-read sequencing technologies, most of the genome assemblies that were produced were highly fragmented, limiting their utility for many downstream genomic analyses. The appearance of new technologies in the field of genome assembly has simplified the process and improved the quality of the resulting assemblies. The steps for producing a reference genome include contig assembly, sequence polishing, chromosome-level scaffolding and manual curation of the final assembly. A reference genome assembly allows multiple genomic analyses, which can greatly benefit the design of conservation plans

A chromosome‐level genome assembly enables the identification of the follicule stimulating hormone receptor as the master sex‐determining gene in the flatfish Solea senegalensis

Data de publicació electrònica: 01-01-2023Includes supplementary materials for the online appendix.Sex determination (SD) shows huge variation among fish and a high evolutionary rate, as illustrated by the Pleuronectiformes (flatfishes). This order is characterized by its adaptation to demersal life, compact genomes and diversity of SD mechanisms. Here, we assembled the Solea senegalensis genome, a flatfish of great commercial value, into 82 contigs (614 Mb) combining long- and short-read sequencing, which were next scaffolded using a highly dense genetic map (28,838 markers, 21 linkage groups), representing 98.9% of the assembly. Further, we established the correspondence between the assembly and the 21 chromosomes by using BAC-FISH. Whole genome resequencing of six males and six females enabled the identification of 41 single nucleotide polymorphism variants in the follicle stimulating hormone receptor (fshr) consistent with an XX/XY SD system. The observed sex association was validated in a broader independent sample, providing a novel molecular sexing tool. The fshr gene displayed differential expression between male and female gonads from 86 days post-fertilization, when the gonad is still an undifferentiated primordium, concomitant with the activation of amh and cyp19a1a, testis and ovary marker genes, respectively, in males and females. The Y-linked fshr allele, which included 24 nonsynonymous variants and showed a highly divergent 3D protein structure, was overexpressed in males compared to the X-linked allele at all stages of gonadal differentiation. We hypothesize a mechanism hampering the action of the follicle stimulating hormone driving the undifferentiated gonad toward testis.This study was supported by the Spanish Ministry of Economy and Competitiveness, FEDER Grants (RTI2018-096847-B-C21, RTI2018-096847-B-C22 and RTI2018-097110-B-C21), Junta de Andalucía-FEDER Grant (P20-00938) and the European Union's Horizon 2020 research and innovation programme under grant agreement No. 817923 (AQUA-FAANG). We thank Geneaqua SL for their participation and financial support of sequencing. We acknowledge the bioinformatic support of the Centro de Supercomputación de Galicia (CESGA)

A reference genome sequence for the european silver fir (abies alba mill.): a community-generated genomic resource

Silver fir (Abies alba Mill.) is a keystone conifer of European montane forest ecosystems that has experienced large fluctuations in population size during during the Quaternary and, more recently, due to land-use change. To forecast the species' future distribution and survival, it is important to investigate the genetic basis of adaptation to environmental change, notably to extreme events. For this purpose, we here provide a first draft genome assembly and annotation of the silver fir genome, established through a community-based initiative. DNA obtained from haploid megagametophyte and diploid needle tissue was used to construct and sequence Illumina paired-end and mate-pair libraries, respectively, to high depth. The assembled A. alba genome sequence accounted for over 37 million scaffolds corresponding to 18.16 Gb, with a scaffold N50 of 14,051 bp. Despite the fragmented nature of the assembly, a total of 50,757 full-length genes were functionally annotated in the nuclear genome. The chloroplast genome was also assembled into a single scaffold (120,908 bp) that shows a high collinearity with both the A. koreana and A. sibirica complete chloroplast genomes. This first genome assembly of silver fir is an important genomic resource that is now publicly available in support of a new generation of research. By genome-enabling this important conifer, this resource will open the gate for new research and more precise genetic monitoring of European silver fir forests