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DGIMI - Diversity, Genomes and Insects-Microorganisms Interactions

DGIMI is a joint research unit supervised by INRAE and the University of Montpellier. It is located on the Triolet campus of the University of Montpellier, and houses staff from both INRAE and UM.

The research carried out by UMR DGIMI is devoted to the study of interaction mechanisms between insect crop pests, their pathogens and parasites, and their host plants. This research takes into account the diversity of the partners and is based on knowledge of their genomes.

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HAL : Dernières publications

  • [hal-05213997] Lepidopteran Genomes Have Denser Transposable Elements in Smaller Chromosomes, Likely Driven by Non-allelic Homologous Recombination

    Transposable elements (TEs) drive major genome size and structural variations, yet evolutionary forces affecting their accumulation and removal remain unclear. Classical models predict that higher recombination rates lead to more efficient purifying selection, such as TE removal. However, in the painted lady butterfly (Vanessa cardui), smaller chromosomes harbor denser TE content than larger ones despite higher recombination rates. This unexpected pattern raises questions about whether similar trends occur across other Lepidoptera species and what evolutionary forces are behind this pattern. Across ten species spanning ten lepidopteran families, we investigated the relationship between chromosome size and TE organization using comparative genomics. We observed that smaller chromosomes consistently have higher TE densities in all the investigated species. Chromosome size had positive correlations with average inter-TE distance for both young (<5% divergence) and old TEs (5% to 10% divergence). However, the ratio of these distances (young/old TEs) was negatively correlated with chromosome size in eight of ten species, with two showing no statistically significant correlation, suggesting that smaller chromosomes have higher removal rates of sequence between TEs, potentially due to nonallelic homologous recombination, causing the loss of unique sequences between nonallelic homologs. Population genomics analyses showed inconsistent correlations between chromosome size and genetic diversity or selection coefficients between Danaus plexippus and Spodoptera frugiperda, ruling out the efficiency of purifying selection or selective constraint as the main driver. Taken together, we demonstrate that Lepidoptera has a unique genomic feature of denser TEs in smaller chromosomes, with nonallelic homologous recombination as a potential driving force.

    ano.nymous@ccsd.cnrs.fr.invalid (Hyerin An) 19 Aug 2025

    https://hal.inrae.fr/hal-05213997v1
  • [hal-05200120] Convergence in Symbiont‐Induced Plant‐Mediated Responses to Herbivory: Cascading Effects for Foraging Parasitoids

    Convergent evolution arises when unrelated species develop similar traits without a shared ancestral origin possessing those characteristics. While typically observed at the organismal level, it can also occur at higher levels of biological organisation. Polydnaviruses represent a striking example of convergent evolution. These viruses, divided into bracoviruses and ichnoviruses, were independently acquired by braconid and ichneumonid parasitoid wasps respectively, to deliver pathogenic genes to caterpillar hosts. Here we show convergent patterns across trophic levels, demonstrating that both bracoviruses and ichnoviruses induce changes in plant‐phenotypic traits that specifically benefit their parasitoid partners, facilitating plant‐mediated host discrimination. This is achieved through an interaction network triggered by changes in the polydnavirus‐infected herbivore (via alteration in regurgitant composition) which eventually affected parasitoids' foraging decisions. Our findings unveil a novel ecological benefit that polydnaviruses offer to their parasitoid partners through intricate, plant‐mediated effects, providing evidence of convergence in symbiont‐induced responses in terrestrial trophic systems.

    ano.nymous@ccsd.cnrs.fr.invalid (Antonino Cusumano) 05 Aug 2025

    https://hal.inrae.fr/hal-05200120v1
  • [pasteur-05212164] Summary of taxonomy changes ratified by the International Committee on Taxonomy of Viruses (ICTV) from the Animal DNA Viruses and Retroviruses Subcommittee, 2025

    The International Committee on Taxonomy of Viruses (ICTV) holds a ratification vote annually after review of newly proposed taxa by ICTV Study Groups and members of the virology community. In March 2025, the vote outcome of the 11 proposals within the mandate of the Animal DNA Viruses and Retroviruses Subcommittee was made public. Here, we provide a summary of the newly accepted proposals. These include reorganization of taxa in the realm Varidnaviria , classification of the ‘polinton-like’ viruses into a new family ( Phypoliviridae ) within a new order Archintovirales ; establishment of a new phylum ( Commensaviricota ) in the kingdom Shotokuvirae ; the establishment of a new family called Filamentoviridae with two new genera and three new species; the addition of four new genera in the family Anelloviridae with 70 new species; and the addition of 85 new species in the families Adenoviridae ( n =16), Baculoviridae ( n =5), Circoviridae ( n =5), Parvoviridae ( n =55) and Polyomaviridae ( n =4). Also, in the family Belpaoviridae , 11 species were renamed to comply with the binomial requirement for species names.

    ano.nymous@ccsd.cnrs.fr.invalid (Arvind Varsani) 17 Aug 2025

    https://pasteur.hal.science/pasteur-05212164v1

News

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18 July 2025

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

A University of Montpellier's Associated Professor in microbiology position (sections 64-65) has been created in DGIMI

Applications must be submitted on Odyssée before 04/04/2025.
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A new scientific publication

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Invasive populations in Senegal show evidence of adaptive evolution on CYP450 genes that may explain their adaptation to maize

photo Peter Heeling

Website under restructuring

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Our website is currently being restructured.

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