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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-05410672] Transgenerational effects of a high temperature impair the resistance of the pest Spodoptera frugiperda to a parasitoid

    Insect parasitoids provide a useful ecosystem service to control pest insects. However, climate change could challenge this pest management, as insects are known to be sensitive to temperature. Furthermore, transgenerational effects, which are common in insects, could influence these effects of temperature on host-parasitoid systems. The present study therefore aimed to test the combined effects of developmental and host parental temperatures on a host-parasitoid system, using the fall armyworm (FAW) and the parasitoid Hyposoter didymator. We focused on mean temperatures of 25 and 29 °C, with a daily fluctuation of ±5 °C. The increase in mean temperatures had a significant effect on all the host parameters tested (survival, developmental rate, sex ratio, body mass) and on parasitoid success. Parasitoid success decreased between the developmental temperatures of 25 and 29 °C, and most effects of the increase in developmental temperature on FAW traits were detrimental to the parasitoid. Remarkably, we found transgenerational effects of temperature on the host resistance to parasitoids (the proportion of FAW escaping parasitism), as well as on host traits associated with the probability of parasitoids finding a host (effects on survival and developmental rates) and host quality (body mass, sex ratio). The parental temperature of 29 °C had a detrimental effect on the FAW resistance to parasitoids, but it reinforced the effects of developmental temperature on host traits that have a negative impact on parasitoids. The study shows the high thermal sensitivity of a host-parasitoid system and highlights that thermal transgenerational plasticity should be considered in host-parasitoid interactions.

    ano.nymous@ccsd.cnrs.fr.invalid (Shannon Alary) 11 Dec 2025

    https://hal.inrae.fr/hal-05410672v1
  • [hal-05438464] Unveiling the Impact of Porphyromonas gingivalis ‐Associated Periodontitis on Stroke Outcome in Mice

    Background Periodontitis is a chronic inflammatory condition with infectious origin that affects the tissues supporting the teeth. Increasing epidemiological evidence suggests that periodontitis is a risk factor for ischemic stroke with associated adverse outcomes. However, the underlying mechanism of this association remains incompletely elucidated. Methods We used a C57BL/6J mice model of ischemic stroke induced by transitory occlusion of the middle cerebral artery in the presence or absence of ligature‐induced periodontitis using Porphyromonas gingivalis ‐soaked ligatures. Stroke severity was evaluated through infarct volume, sensorimotor deficit, blood–brain barrier (BBB) integrity, and markers of systemic and brain inflammation. The direct effect of P gingivalis on BBB endothelial cells was further explored in vitro. Results Mice with P gingivalis ‐associated periodontitis showed a significant exacerbation of stroke severity: larger infarct volume, more severe sensorimotor deficit, greater BBB disruption, and increased brain neutrophil infiltration compared with sham. Systemic inflammation was also markedly elevated. Intravenous administration of P gingivalis alone, without gingival injury, before transitory occlusion of the middle cerebral artery was sufficient to amplify brain inflammation and stroke lesions. In vitro P gingivalis, through its gingipain proteases, directly impaired BBB integrity by increasing endothelial permeability and disrupting tight‐junction proteins. Conclusions Our findings demonstrate that P gingivalis ‐associated periodontitis worsens ischemic stroke outcome both indirectly by enhancing systemic and brain inflammation and directly via BBB disruption. These results highlight periodontitis as a modifiable risk factor and potential therapeutic target for improving stroke prognosis.

    ano.nymous@ccsd.cnrs.fr.invalid (Devy Diallo) 02 Jan 2026

    https://u-paris.hal.science/hal-05438464v1
  • [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

News

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article

15 January 2026

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

DGIMI is hiring in 2026

Best wishes for the new year 2026! To support your professional development, the DGIMI laboratory has several job openings for technicians, assistant engineers, teacher-researchers, and researchers.
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12 01

12 January 2026

Université de Montpellier, campus sciences

Lucturer postion in Nematology

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A permanent lecturer position is likely to become available in 2026 at the University of Montpellier.

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

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Applications must be submitted on Odyssée before 04/04/2025.

Our new article makes the cover of AEM

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Nematodes are used in biological control to combat insect pests. To complete their infectious cycle, they are assisted by their symbiotic bacteria Xenorhabdus, which produces a multitude of different metabolites. Among these metabolites, Xenorhabdus produces PAX cyclolipopeptides, whose role in the ecological cycle of the bacteria was poorly understood.