logo umr
Génétique Quantitative et Évolution - Le Moulon

Judith LEGRAND

Judith LEGRAND

Maitre de conférences, Université Paris-Saclay

Biomathematics and biostatistics

  • Adaptation,,
  • life-history,
  • strategies,,
  • intra,
  • and,
  • inter-specific,
  • interactions,,
  • mathematical,
  • models,,
  • yeast

judith.legrand@inrae.fr

01 69 33 23 49

orcid.org/0000-0001-5157-9268

Publications

  • Génétique Quantitative et Évolution - Le Moulon
  • Université Paris-Saclay, INRAE, CNRS, AgroParisTech
  • Ferme du Moulon
  • F-91190 Gif-sur-Yvette

Position and education

  • Since February 2019 : Head of BASE team
  • Since 2011: Assistant professor Université Paris-Sud, Génétique Quantitative et Évolution - Le Moulon
  • 2010-2011: Post-doctoral researcher, Risk modeling and surveillance for health safety lab, Conservatoire national des Arts et Métiers and Epidemiology, Information systems, Modeling lab, INSERM-UPMC UMR-S 707, Paris - Dynamics of methicillin-resistant Staphylococcus aureus in a rehabilitation centre
  • 2007-2010: Post-doctoral position in the MRC Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, Imperial College, London - Methodological development to characterize epidemics. Applications to anthrax and influenza.
  • 2006-2007: Research engineer, Epidemiology, Information systems, Modeling lab, INSERM-UPMC UMR-S 707, Paris
  • 2006: PhD in biomathematics, Université Pierre et Marie Curie, Paris - Mathematical modeling and the preparedness against bioterrorist attacks: an application to Ebola hemorrhagic fever and smallpox.

Research interests

I use mathematical and statistical modelling to understand the role of adaptation in the evolution of life-history strategies and the structure of communities. My current research projects are:

Impact of phenology on maize-pest interactions

coll. Laure Kaiser, François Rebaudo (EGCE, Paris-Saclay), Christine Dillmann, Adrienne Ressayre, Élodie Marchadier (GQE-Le Moulon), past-student : Inoussa Sanane

Plants can escape herbivores either by building up defenses such as plant secondary compounds, or by shortening their life-cycle so that they become mature before herbivore attacks. In France, Lepidoptera stem borers have a two-generations/year life-cycle. In spring, adult females lay eggs on young leaves. During summer, second generation caterpillars enter plant stems and dig galleries until ears. Completion of life-cycle occurs in non-harvested cobs during winter. Among tools for biological pest controls, sowing early maize varieties is recommended because maize stems are stronger when the second-generation larvae arise and better resist invasion. We are investigating how plant phenology shifts interfere with Lepidoptera stem borers life-cycle using theoretical and experimental approaches in the field.

Adaptation and life-history strategies

coll. Delphine Sicard and Thibault Nidelet (SPO, INRA), Sylvie Mélard (Ecole Polytechnique) - past student: Dorian Collot, PhD thesis, June 2018.

Adaptation of organisms to their environment relies on many phenotypic traits called life-history traits. Due to physical and biological constraints, selection cannot maximize all those traits together. Hence analyzing the evolution of several traits jointly will enhance our understanding of adaptation dynamics.

We are interested in the adaptation of the yeast Saccharomyces cerevisiae via several traits related to fermentation and respiration such as resource consumption rate, biomass yield or mortality. Two extreme life-history strategies have been identified from experimental data. We are developing models to highlight the components of fitness in a seasonal environment and to understand how the seasonality can shape the evolution of traits and their relation.

Structure of microbial communities in natural sourdough

coll. Delphine Sicard and Elisa Michel (SPO, INRA), Xavier Doucet and Bernard Onno (Oniris) - past post-doc: Johan Ramsayer, past-student : Charlotte Urien

Microbial communities are ubiquitous across earth ecosystems. The recent –omics technics have highlighted their complex structure but very little is known about the ecological processes and the interactions between species shape their pattern. Wheat sourdough's microbial communities are relatively simple communities which can provide a useful model to study ecological processes structuring communities. Sourdough communities are composed of an assemblage of lactic acid bacteria and yeasts species, varying from one sourdough to another. With my collaborators, we are mixing experimental and theoretical approaches to understand how intra and inter-specific interactions shape the structure of the microbial communities observed in sourdough.

Teaching

Licence:

  • Statistical tests for biologists
  • Ecology and statistics
  • Modeling biological systems with ordinary differential equations
  • Introduction to programming
  • Co-director of the “Licence Double Diplôme Mathématiques, Sciences de la Vie” (bachelor degree in both life sciences and mathematics)

Master 1:

  • Biostatistics

Master 2:

  • Introduction to mathematical models of infectious diseases dynamics
  • Introduction to statistical data analysis for optometrists and ergonomists
  • Big data

Publications

Harlé O, Legrand J, Tesnière C, Pradal M, Mouret JR, Nidelet T, Ohya Y. (2020) Investigations of the mechanisms of interactions between four non-conventional species with Saccharomyces cerevisiae in oenological conditions. PLoS ONE, 5 (15) e0233285
Sanane I, Legrand J, Dillmann C, Marion-Poll F. (2020) A semi-automated design for high-throughput Lepidoptera larvae feeding bioassays. bioRxiv, 2020.08.02.232256
Urien C, Legrand J, Montalent P, Casaregola S, Sicard D. (2019) Fungal Species Diversity in French Bread Sourdoughs Made of Organic Wheat Flour. Front. Microbiol., (10) 201
Carbonetto B, Ramsayer J, Nidelet T, Legrand J, Sicard D. (2018) Bakery yeasts, a new model for studies in ecology and evolution. Yeast, 11 (35) 591-603
Collot D, Nidelet T, Ramsayer J, Martin OC, Meleard S, Dillmann C, Sicard D, Legrand J. (2018) Feedback between environment and traits under selection in a seasonal environment: consequences for experimental evolution. Proceedings. Biological sciences, 1876 (285)
Spor A, Kvitek DJ, Nidelet T, Martin J, Legrand J, Dillmann C, Bourgais A, de Vienne D, Sherlock G, Sicard D. (2014) Phenotypic and genotypic convergences are influenced by historical contingency and environment in yeast. Evolution; international journal of organic evolution, 3 (68) 772-90