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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-05473549] Four nudivirus core genes present in the genome of Venturia canescens are required for virus-like particle formation and prevention of encapsulation of parasitoid wasp eggs

    ABSTRACT Venturia canescens is a parasitoid wasp that harbors a domesticated endogenous virus (DEV) and parasitizes host insects like Ephestia kuehniella . The V. canescens DEV evolved from an alphanudivirus and produces virus-like particles (VLPs) in females that protect wasp eggs from a host immune defense called encapsulation. In contrast, very few DEV genes required for VLP formation and function have been identified. In this study, we characterized five V. canescens DEV genes of unknown function that all nudiviruses encode. Three of these genes are single copy ( OrNVorf18-like , OrNVorf61-like , and OrNVorf76-like ), while OrNVorf41-like has expanded into a six-member family and OrNVorf47-like has expanded into a three-member family. Sequence analysis indicated all of these genes retain essential motifs present in nudivirus homologs, while transmission electron microscopy (TEM) studies characterized the timing of VLP formation during the wasp pupal stage. RNA interference (RNAi) assays identified OrNVorf18-like , OrNVorf61-like , OrNVorf41-like-1, and OrNVorf41-like-2 as genes that are required for normal VLP formation. Knockdown of OrNVorf47-like family members did not affect VLP formation but did disable binding of VLPs to V. canescens eggs and protection against encapsulation. Disabled formation of VLPs in response to RNAi knockdown of OrNVorf18-like , OrNVorf61-like , OrNVorf41-like-1, and OrNVorf41-like-2 also resulted in wasp eggs being encapsulated. In contrast, knockdown of OrNVorf76-like had no effect on VLP assembly, egg binding, or encapsulation. Altogether, reported results significantly advance our understanding of V. canescens VLP (VcVLP) formation and function. IMPORTANCE Understanding how V. canescens coopted an alphanudivirus to produce VcVLPs is of interest to the study of virus evolution. Our results show that three nudivirus core genes have essential functions in VcVLP formation, while one is essential for the novel function of binding to wasp eggs and protection from encapsulation, which is the most important immune defense of insects against parasitoids.

    ano.nymous@ccsd.cnrs.fr.invalid (Meng Mao) 23 Jan 2026

    https://hal.science/hal-05473549v1
  • [hal-05495582] Identification of differential metabolic properties potentially involved in the expansion of Enterobacteriaceae in the dysbiotic gut of patients suffering from Crohn’s Disease or Rheumatoid Arthritis.

    [...]

    ano.nymous@ccsd.cnrs.fr.invalid (Maria Ines Moreira de Gouveia) 05 Feb 2026

    https://hal.inrae.fr/hal-05495582v1
  • [hal-05534918] Is the extreme within-population genome size variation real in Spodoptera frugiperda?

    Genome size variation is one of the main topics in evolutionary genomics. Recent studies in Spodoptera frugiperda (Insect; Lepidoptera) reported very striking results, including large genome size differences, up to a twofold variation within populations, with the existence of 1.37 Gb of non-reference genome sequences, which is 2.5 times larger than the reference genome, 544 Mb in size. These reports raise the question of whether such extreme genome size variations within populations can be biologically realistic. To evaluate these results, we analyzed reference genome assemblies and resequencing datasets from multiple independent studies, including those from the original research. We observed that high-quality reference genomes consistently range from 380 Mb to 390 Mb, aligning closely with flow cytometry measurements. The genome size estimates using k-mer-based approaches from field-collected samples across four independent studies suggest that extensive genome size variation within S. frugiperda is unlikely to occur. Additionally, genome size appears to have remained stable for at least 15.89 million years in the ancestral lineage of S. frugiperda . Taken together, these results do not support the existence of extreme genome size variation in S. frugiperda , emphasizing the need for careful validation.

    ano.nymous@ccsd.cnrs.fr.invalid (Karine Durand) 03 Mar 2026

    https://hal.inrae.fr/hal-05534918v1

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