Publications by authors named "Legeai F"

The expansion of multi-omics datasets raises significant challenges for data integration and querying. To overcome these challenges, we developed a generic RDF-based integration schema that connects various types of differential -omics data, epigenomics, and regulatory information. This schema employs the FALDO ontology to enable querying based on genomic locations.

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  • The first nuclear genome assembly and complete mitochondrial genome (mitogenome) for Hylesia metabus, a species of moth, has been presented, with the nuclear genome being one of the largest for lepidopterans at 1,271 Mb.
  • The nuclear genome is organized into 31 pseudo chromosomes with a high quality BUSCO score of 99.5%, and contains a significant amount of repetitive elements, primarily located in intergenic regions.
  • The assembled genomes are available on the BIPAA website and will aid future studies in population and comparative genomics.
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In order to capture the drought impacts on seed quality acquisition in Brassica napus and its potential interaction with early biotic stress, seeds of the 'Express' genotype of oilseed rape were characterized from late embryogenesis to full maturity from plants submitted to reduced watering (WS) with or without pre-occurring inoculation by the telluric pathogen Plasmodiophora brassicae (Pb + WS or Pb, respectively), and compared to control conditions (C). Drought as a single constraint led to significantly lower accumulation of lipids, higher protein content and reduced longevity of the WS-treated seeds. In contrast, when water shortage was preceded by clubroot infection, these phenotypic differences were completely abolished despite the upregulation of the drought sensor RD20.

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  • Thousands of endoparasitoid wasp species from the Braconidae and Ichneumonidae families carry domesticated endogenous viruses (DEVs), specifically ichnoviruses (IVs), in their genomes.
  • The study focuses on how large quantities of IV virions are produced in the ovary calyx cells of female wasps, especially during pupal and adult stages, and how these virions aid in the successful development of wasp offspring by infecting host insects.
  • Researchers generated a detailed genome assembly for the Hyposoter didymator wasp and identified 67 HdIV loci, concluding that a specific gene, U16, is crucial for both the amplification of these loci and the formation of vir
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  • The study investigates the male-killing effects of the endosymbiotic bacteria Spiroplasma ixodetis on pea aphids, analyzing its genome to understand its virulence factors.
  • It identifies a complete genome sequence for a male-killing strain, which lacks the Spaid toxin found in other Spiroplasma strains but contains various potential virulence factors.
  • The research emphasizes the evolutionary dynamics of S. ixodetis and suggests that different male-killing strategies may have evolved independently in various insect species.
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We present the first chromosome-level genome assembly and annotation of the pearly heath Coenonympha arcania, generated with a PacBio HiFi sequencing approach and complemented with Hi-C data. We additionally compare synteny, gene, and repeat content between C. arcania and other Lepidopteran genomes.

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Background: Transitions from sexual to asexual reproduction are common in eukaryotes, but the underlying mechanisms remain poorly known. The pea aphid-Acyrthosiphon pisum-exhibits reproductive polymorphism, with cyclical parthenogenetic and obligate parthenogenetic lineages, offering an opportunity to decipher the genetic basis of sex loss. Previous work on this species identified a single 840 kb region controlling reproductive polymorphism and carrying 32 genes.

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  • The research investigates the genetics behind the loss of sexual reproduction in the pea aphid, specifically comparing cyclical parthenogenetic (CP) and obligate parthenogenetic (OP) lineages.
  • An 840-kb X-linked genomic region was identified that correlates with reproductive modes, displaying significant divergence between CP and OP populations.
  • Despite this divergence, low genetic differentiation in the rest of the genome suggests ongoing gene flow between CP and OP lineages, which may aid in the survival of both reproductive strategies under varying environmental conditions.
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Background: Local assembly with short and long reads has proven to be very useful in many applications: reconstruction of the sequence of a locus of interest, gap-filling in draft assemblies, as well as alternative allele reconstruction of large Structural Variants. Whereas linked-read technologies have a great potential to assemble specific loci as they provide long-range information while maintaining the power and accuracy of short-read sequencing, there is a lack of local assembly tools for linked-read data.

Results: We present MTG-Link, a novel local assembly tool dedicated to linked-reads.

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The role of lncRNAs in immune defence has been demonstrated in many multicellular and unicellular organisms. However, investigation of the identification and characterization of long non-coding RNAs (lncRNAs) involved in the insect immune response is still limited. In this study, we used RNA sequencing (RNA-seq) to investigate the expression profiles of lncRNAs and mRNAs in the fall armyworm in response to virus infection.

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The ithomiine butterflies (Nymphalidae: Danainae) represent the largest known radiation of Müllerian mimetic butterflies. They dominate by number the mimetic butterfly communities, which include species such as the iconic neotropical Heliconius genus. Recent studies on the ecology and genetics of speciation in Ithomiini have suggested that sexual pheromones, colour pattern and perhaps hostplant could drive reproductive isolation.

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The fall armyworm (FAW; Spodoptera frugiperda) is one of the major agricultural pest insects. FAW is native to the Americas, and its invasion was first reported in West Africa in 2016. Then it quickly spread through Africa, Asia, and Oceania, becoming one of the main threats to corn production.

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Background: Divergent selection on host-plants is one of the main evolutionary forces driving ecological speciation in phytophagous insects. The ecological speciation might be challenging in the presence of gene flow and assortative mating because the direction of divergence is not necessarily the same between ecological selection (through host-plant adaptation) and assortative mating. The fall armyworm (FAW), a major lepidopteran pest species, is composed of two sympatric strains, corn and rice strains, named after two of their preferred host-plants.

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The bitter taste, triggered via gustatory receptors, serves as an important natural defense against the ingestion of poisonous foods in animals, and the increased host breadth is usually linked to an increase in the number of gustatory receptor genes. This has been especially observed in polyphagous insect species, such as noctuid species from the Spodoptera genus. However, the dynamic and physical mechanisms leading to these gene expansions and the evolutionary pressures behind them remain elusive.

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Nitrogen fertilization has been reported to influence the development of clubroot, a root disease of species, caused by the obligate protist . Our previous works highlighted that low-nitrogen fertilization induced a strong reduction of clubroot symptoms in some oilseed rape genotypes. To further understand the underlying mechanisms, the response to infection was investigated in two genotypes "Yudal" and HD018 harboring sharply contrasted nitrogen-driven modulation of resistance toward .

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  • Oilseed rape is the third largest oil crop globally but faces challenges from drought and clubroot disease, which negatively affect seed yield and quality.
  • Drought primarily impacts yield, while clubroot disease, caused by a specific pathogen, creates root galls that hinder nutrient and water flow in the plant.
  • A new RNA-seq dataset of 72 immature seed samples was created to study the plant's response to these stresses, providing valuable insights and resources for researchers in plant resilience, available at NCBI SRA under accession PRJNA738318.
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Ecological speciation entails divergent selection on specific traits and ultimately on the developmental pathways responsible for these traits. Selection can act on gene sequences but also on regulatory regions responsible for gene expression. Mimetic butterflies are a relevant system for speciation studies because wing colour pattern (WCP) often diverges between closely related taxa and is thought to drive speciation through assortative mating and increased predation on hybrids.

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Motivation: Linked-Reads technologies combine both the high quality and low cost of short-reads sequencing and long-range information, through the use of barcodes tagging reads which originate from a common long DNA molecule. This technology has been employed in a broad range of applications including genome assembly, phasing and scaffolding, as well as structural variant calling. However, to date, no tool or API dedicated to the manipulation of Linked-Reads data exist.

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(Ichneumonoidea, Braconidae) is an endoparasitoid wasp of lepidopteran caterpillars. Its parasitic success relies on vesicles (named Virus-Like Particles or MpVLPs) that are synthesized in the venom gland and injected into the parasitoid host along with the venom during oviposition. In order to define the content and understand the biogenesis of these atypical vesicles, we performed a transcriptome analysis of the venom gland and a proteomic analysis of the venom and purified MpVLPs.

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There is increasing awareness that interactions between plants and insects can be mediated by microbial symbionts. Nonetheless, evidence showing that symbionts associated with organisms beyond the second trophic level affect plant-insect interactions are restricted to a few cases belonging to parasitoid-associated bracoviruses. Insect parasitoids harbour a wide array of symbionts which, like bracoviruses, can be injected into their herbivorous hosts to manipulate their physiology and behaviour.

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  • The aphid Myzus persicae is a major agricultural pest known for quickly developing resistance to insecticides, making it a challenge for farmers.
  • Researchers generated a comprehensive genome assembly and sequenced over 110 clonal lines from worldwide populations to study the genetic basis of this resistance.
  • The study found significant genetic diversity in resistance mutations influenced by the aphid's host plants, revealing both repeated mutations at the same genetic locus and new resistance mechanisms, which can inform better pest control strategies.
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Starvation is frequently encountered by animals under fluctuating food conditions in nature, and response to it is vital for life span. Many studies have investigated the behavioral and physiological responses to starvation. In particular, starvation is known to induce changes in olfactory behaviors and olfactory sensitivity to food odorants, but the underlying mechanisms are not well understood.

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Most metazoans are associated with symbionts. Characterizing the effect of a particular symbiont often requires getting access to its genome, which is usually done by sequencing the whole community. We present MinYS, a targeted assembly approach to assemble a particular genome of interest from such metagenomic data.

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