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DGIMI est une unité mixte de recherche ayant pour tutelles INRAE et l'Université de Montpellier. Elle est située sur le campus Triolet de l'Université de Montpellier et accueille une trentaine de personnels INRAE et UM.

Les recherches développées dans l'UMR DGIMI visent à mieux comprendre les interactions entre les insectes et leur environnement biotique et abiotique dans les agrosystèmes, selon deux axes thématiques 

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HAL : Dernières publications

  • [hal-05090442] Deciphering the methylome of a bacterial oyster pathogen, Vibrio aestuarianus

    DNA methylation in Bacteria was discovered in the 1960s, but studies linking methylation modification to phenotype changes remain rare. Deregulation of DNA-methyltransferases (DNA MTases) has been shown to be associated with significant phenotypic shift, such as virulence attenuation in Vibrio cholerae[1]. Contrary to eukaryotes, bacterial DNA methylation occurs only on specific motifs, with the majority (>94%) being methylated. Multiple studies have demonstrated the global stability of the methylome at different growth stages or under different conditions, and a few promoter-region modifications have been associated with gene regulation and phenotypic changes[2]. In marine ecosystems, where bacteria face constant environmental variations, the importance of epigenetics on pathogens cycle is still unclear. V. aestuarianus is a marine bacterial pathogen that clonally expanded over Europe in the last 20 years[3]. It causes massive mortality events for Magallana gigas oysters, leading to substantial economic losses in the European aquaculture industry. Yet the molecular mechanisms driving oyster colonization and virulence remain unknown. Environmental factors such as temperature, salinity, 02 and rainfall strongly influence the susceptibility to the bacteria. Notably, decreased salinity induces higher mortality. However, the molecular mechanisms underlying this salinity-dependent virulence remain poorly characterized. To address the effect of salinity, bacterial cultures were performed at different environmental salinities (15, 30 and 40 g/l) for methylome (SMRT-seq) and transcriptome (RNA-seq) monitoring. An initial genomic analysis revealed 10 DNA MTases in V. aestuarianus 12/016 (4 solitary, 6 in Restriction-Modification system, 8 being consistently expressed), comparable to studies showing methylome modifications associated with phenotype changes. The sequencing effort (~600X) revealed four highly methylated (>99%) m6A motifs (GATC, CAGNNNNNNTYTC, TAACNNNNRTAC, ACCNNNNNNNTTCY) and one m4C motif (>96%, GGWCC). A potential m5C motif (CGCCG) was also detected. Ongoing analyses aim to find potential methylation changes in promoter regions associated with virulence.

    ano.nymous@ccsd.cnrs.fr.invalid (Elyna Bouchereau) 30 May 2025

    https://hal.science/hal-05090442v1
  • [hal-05072238] Analyse fonctionnelle des gènes conservés au cours de la domestication virale chez un parasitoïde ichneumonide.

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    ano.nymous@ccsd.cnrs.fr.invalid (Anne-Nathalie Volkoff) 18 May 2025

    https://hal.inrae.fr/hal-05072238v1
  • [hal-05027917] Divergent Selection Promotes Intraspecific Genomic Differentiation in Spodoptera littoralis With Possible Involvement in Detoxification

    The cotton leafworm, Spodoptera littoralis (Lepidoptera: Noctuidae), is a major agricultural pest affecting crops like cotton, maize, tomatoes, and wheat across southern Europe, Africa, the Middle East, and western Asia. Whole genome analyses have revealed adaptive evolution in chemosensation and detoxification genes in S. littoralis. However, the extent of intraspecific diversity influenced by recent adaptive evolutionary forces remains unclear. In this study, we conducted a population genomics analysis using 31 S. littoralis individuals from sub-Saharan Africa, northern Africa, and southern Europe to assess the existence of intraspecific population divergence and identify the underlying evolutionary forces. We show whole genome differentiation between populations based on geographic origin from the analyzed samples. Phylogenetic analyses indicate that sub-Saharan and southern European populations share a common ancestor, distinct from several northern African populations. FST and dXY statistics along the chromosomes reveal loci with restricted gene flow among populations. These loci are associated with population-specific selective sweeps, indicating the role of divergent natural selection in limiting gene flow. Notably, these loci are enriched with detoxification genes, including cytochrome P450, multidrug resistance, and xanthine dehydrogenase genes, all of which are potentially associated with detoxification. These results demonstrate that divergent selection limits gene flow among geographically distinct populations with the possibility of the involvement of detoxification as a key trait. We argue that this genetic heterogeneity can be considered in pest monitoring and management, as strategies tailored to specific populations may not be relevant for others.

    ano.nymous@ccsd.cnrs.fr.invalid (Karine Durand) 09 Apr 2025

    https://hal.inrae.fr/hal-05027917v1

Actualités

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article

06 mars 2025

Rédaction : A-N Volkoff, N. Nègre , I. Seninet

Nouvelle publication scientifique

Les populations invasives au Sénégal montrent des traces d’évolution adaptative sur des gènes CYP450 pouvant expliquer leur adaptation au maïs.
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photo Peter Heeling

Site web en cours de maintenance

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Des modifications de structure et de contenus s'opèrent actuellement sur le site web DGIMI

Postdoctoral Position in CRISPR/Cas9 Gene Editing in Insects (University of Montpellier)

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Location: UMR-DGIMI, University of Montpellier, France / Duration: 18 months / Start Date: Preferably from April 2025

News & Views sur l’écologie des viromes d’insectes

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Un commentaire critique de Sarah François (https://www.nature.com/articles/s41559-024-02385-w), chercheuse INRAE à DGIMI, sur un article à fort impact portant sur l'écologie des communautés virales (i.e. viromes) d'insectes.