Accueil

.

Our website is currently being restructured.


We apologize for the inconvenience caused.

For a more up-to-date version, please consult the site in French version
https://dgimi.hub.inrae.fr/

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.

Read more

 

HAL : Dernières publications

  • [hal-05625613] Priority effects drive fungal and nematode emergence from insect larvae

    Abstract Priority effects, in which species arrival history influences community assembly, are increasingly recognized to affect host–parasite systems. However, priority effects across disparate groups of parasitic organisms are poorly understood despite the wide range of taxonomic groups involved. In California oak woodland, we investigated how priority effects between two insect-parasitic fungi (Metarhizium and Beauveria) influenced emergence of nematodes from insect larvae. Field and laboratory results indicated that both fungi were common, but priority effects prevented them from co-emerging from the same larva. Metarhizium- and Beauveria-infected insects did not differ in the species composition of emerging nematodes, but larvae without fungal emergence had distinct nematode communities, with Oscheius almost always emerging without fungi. Experiments indicated that none of the commonly found nematodes (Acrobeloides, Mesorhabditis, Oscheius, and Rhabditis) were entomopathogenic, but that Oscheius could exclude Beauveria if it arrived early. This time-dependent exclusion was likely caused by a bacterium that Oscheius nematodes carried (Serratia proteamaculans). Together, these findings suggest that fungi enter insects as primary arrivers, while nematodes come as secondary arrivers to exploit fungus-killed insects, with priority effects influencing both groups. We suggest that this system is a promising natural microcosm for understanding priority effects across disparate groups in host–parasite systems.

    ano.nymous@ccsd.cnrs.fr.invalid (Amaury Payelleville) 18 May 2026

    https://hal.science/hal-05625613v1
  • [hal-05669785] Investigating the Genetic Underpinnings of Ongoing Fall Armyworm ( FAW ) Range Expansion in Aotearoa New Zealand

    Spodoptera frugiperda (fall armyworm; FAW) is a major agricultural pest native to the Americas, with the first reported invasion of Africa in early 2016. Since then, FAW has spread rapidly across Africa and Asia before invading Australia (2020) and first being detected in Aotearoa New Zealand in February 2022. Here, we assessed the whole genomes of 34 novel FAW individuals along the invasion front (representing three new invasive populations from Cambodia, Australia, and New Zealand) with the largest publicly available global FAW genome dataset ( n = 173), resulting in a dataset of 112 and 99 samples from the invasive and native range, respectively, to: (1) place the new invasive populations within the global invasion; (2) identify the potential geographic origin of the New Zealand invasion, including from a single or multiple incursion event; and (3) assess pre‐existing insecticide resistance potential at the invasion front. We confirm that these new invasions conform to the broad population structure of the initial invasive populations identified in Benin (West Africa), all of which belong to the invasive corn strain, as defined through previous triosephosphate isomerase (TPI) analysis and associated isolation from specific host plants. While we could not confidently assign the source population of the New Zealand invasion, we find preliminary support for a multiple introduction hypothesis in our data, which could contribute to increased genetic diversity within the New Zealand population. Further sampling is therefore required to fully characterise the origins of the New Zealand invasion. In novel samples, we detected putative insecticide resistance alleles previously reported in other invasive populations. These resistant loci should be tracked over time to understand the mechanisms enabling the invasion success of FAW in the Asia‐Pacific region. We emphasise that sharing of genomic resources between institutions and consortia is an essential first step in the control of this global invader.

    ano.nymous@ccsd.cnrs.fr.invalid (Amy Vaughan) 25 Jun 2026

    https://hal.science/hal-05669785v1
  • [hal-05651879] Argonaute protein and small RNA expression patterns in Spodoptera frugiperda (Lepidoptera, Noctuidae)

    PIWI-interacting RNAs (piRNAs) and PIWI proteins were initially described as playing a role in gametogenesis and maintaining genome integrity by controlling transposable elements (TEs). 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 and reproductive isolation. Spodoptera frugiperda (Sf) is a major invasive insect pest species consisting of two strains with distinct host-plant ranges. To identify which pathway was regulated by piRNAs in this species, we characterized proteins and genomic regions involved in their biogenesis, as well as TE and gene transcripts regulated. 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 the gonads than in the 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 Sf strains. Identification of TE targeted by putative piRNAs revealed that active transposons may differ between the two Sf strains, despite a similar TE content, as a 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. Our analysis contributes to functional annotation of the Sf strains genomes and supports additional roles than silencing of transposable elements for piRNAs.

    ano.nymous@ccsd.cnrs.fr.invalid (Imène Séninet) 10 Jun 2026

    https://hal.science/hal-05651879v1

News

All news