Epigenetic, holocentrism and insect adaptation (EHA)

M. Fraysinnet / Simon et al., 2015 / INRAE

Research project

Our group is interested in three main topics related to genome biology: genome expression and regulation, genome stability and evolution, functional organization of the genome that we study in relationship with a complex phenotypic trait - adaptation to the host-plant – in major crop pest insects belonging to the order Lepidoptera, relevant of INRAE’s concerns. The originality of Lepidopteran genomes is the spread of the centromere along chromosome arms (holocentric chromosomes) instead of being located at one place (monocentric ones), which raises several questions in terms of genome biology.

Our main insect model, the moth Spodoptera frugiperda, or “fall armyworm (FAW)” is a pest of crops. It exists as two variants, one found on corn (C strain), the other found on rice or pasture grass (R strain). Both variants coexist in the same geographical areas, initially America, and are morphologically indistinguishable but possible to identify genetically. 

Since 2016, it has become invasive in Africa, India, China, Australia and threats European agricultures. We considered it a good model to study adaptation to the host-plant and the process of speciation - possibly sympatric in this case, in presence of gene flow. 

Our objectives in 2015-2020 have been to characterize phenotypic differences related to adaptation and speciation between the two variants and to link them to molecular differences by comparative – transcriptomics, epigenomics, genomics and population genomics

Our goals for the next five years 2021-2025 is the study of:

• Expression of the holocentric genome during phenotypic plasticity and adaptation (N. Nègre) 
• Adaptation to the plant, of speciation and invasion processes in the genus Spodoptera (K. Nam)
• The consequences of holocentric structure on genome expression and evolution (E. d’Alençon)

Fundings, led by EHA

• Genoscope project 2011-2017 WGS  consortium FAW-IPC PI 2011-2013, P. Fournier, PI 2014-2017, E. d’Alençon
• ANR ADA-SPODO 2013-2017 PI, E. d’Alençon
• IUF project 2013-2018 PI, N. Nègre
• INRAE SPE project ADAPTIVESV 2017-2019 PI, K. Nam
• Agropolis Fondation Project ADAPTIVSPODO 2018-2019 PI, K. Nam
• INRAE SPE project HOLOCENTRISM 2018-2021 PI, E. d’Alençon
• INRAE SPE project SPODORICE 2020-2022 PI, N. Nègre
• INRAE SPE project NEWHOSTS 2021-2022 PI, K. Nam
• ANR-DFG project ORIGINs 2021-2023 PI, E d’Alençon

Main partners

• INRAE CBGP (G. Kergoat, R. Streiff), iEES (E.Jacquin, C. Meslin), ISA (G. Legoff, F. Hilliou), URGI (H. Quesneville, J. Amselem)
• IRD IPME (P. Silvie) & DIADE (A. Champion)
• CIRAD AIDA (T. Brévault)
• BioInformatics Platform for Agroecosystem Arthropods, BIPAA,  (F. Legeai, A. Bretaudeau, S. Robin)
• MPICE (S. Hanniger, D. Heckel)
• CAAS (Y. Xiao)
• CSIRO (W. Tay, T. Walsh)
• USDA (R. Meagher, R. Nagoshi)

Animation of Networks

•  ADALEP : Funded by the INRA department of Environment and Plant Health and coordinated by Emmanuelle D'Alençon. It comprises 23 French laboratories that focus on the biotic adaptation of Lepidopteran.
• GDR3E : Epigenetic in Ecology and Evolution. Nicolas Nègre is member of the scientific committee.