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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-05374380] A characterization of piARNs, their biogenesis and their targets in Spodoptera frugiperda (Lepidoptera, Noctuidae)

    Abstract PIWI-interacting RNAs (piRNAs) and PIWI proteins were initially described as involved in gametogenesis and preservation of genome integrity through the control of transposable elements (TE). Expressed also in the soma and able to regulate protein coding gene expression, they are involved in multiple biological pathways including host-pathogens interaction, sex determination, reproductive isolation. Spodoptera frugiperda is a major invasive insect pest species consisting of two strains with different host-plant ranges. In this paper, we characterized proteins and genomic regions involved in their biogenesis as well as TE and gene transcripts regulated by piRNAs. By phylogenetic analysis, we identified two new Piwi genes conserved in the genus Spodoptera , compared to the Lepidopteran model Bombyx mori , one more than in Drosophila . One of them, more expressed in gonads then soma could be a functional homolog of Drosophila PIWI or replace AGO3. A pool of 11 sRNA-Seq libraries was used to annotate piRNA clusters with Shortstack in the genomes of the two strains of Spodoptera frugiperda . Identification of TE targeted by piRNAs revealed that active transposons differ between the two strains of S. frugiperda despite of a similar TE content, as putative cause or consequence of reproductive isolation. GO analysis of genes targeted by piRNAs shows that some are involved in protein translation initiation. A piRNA cluster in the Masc gene suggests that sex determination is regulated by piRNAs in Spodoptera frugiperda . Our analysis supports that piRNAs have additional roles than silencing of transposable elements and contributes to functional annotation of the two strains genomes of Spodoptera frugiperda .

    ano.nymous@ccsd.cnrs.fr.invalid (Imène Seninet) 20 Nov 2025

    https://hal.inrae.fr/hal-05374380v1

News

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article

27 October 2025

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

Our new article makes the cover of AEM

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.
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Thesis defense : Shannon Alary

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Congratulations to Shannon Alary for her thesis defense on the effect of temperature on the plasticity of host-parasitoid interactions, supervised by Isabelle Darboux and Manuel Massot (iEES Paris) !

vignette FDS 2025 DGIMI
04 10

From 04 Oct. 2025 to 05 Oct. 2024

Montpellier Science Village (Village des sciences de Montpellier)

Science Festival 2025

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For the 2025 edition, DGIMI Lab, proposed an activity on the theme of “Clever pests and smart microbes.”

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