Project leaders: Christine DILLMANN (GQE-Le Moulon: Quantitative genetics and evolution), Bruno ANDRIEU (ECOSYS: Functional ecology and ecotoxicology of agroecosystems), Arnaud LE ROUZIC (EGCE: Evolution, genomes, behavior, ecology)
Partners

• in BASC: ESE (Ecology, Systematics, Evolution)
• outside BASC: IJPB (Institut Jean-Pierre Bourgin: biology of plants), MaIAGE (Mathematics and computer science applied to the genome and environment)

Using maize as a model crop, and building upon complementarities between project partners, Itemaize will help to (i) better understand how environment impacts plant life-cycles and their interaction with insect pests; (ii) predict the potential for (epi)genetic adaptations and (iii) define selection criteria for crop life-cycle shifts. The project will also sustain methodological developments on phenotyping, data analyses and modelling.

Bringing partners from different disciplines, the project relies on a unique plant material resulting from 20 years of divergent selection for flowering time performed in the Plateau de Saclay. Selecting each year for early and late flowering from a narrow genetic diversity (two inbred lines), we created an evolved plant material likely to be enriched in (epi)genetic differences related to flowering time, while preserving the original characteristics of the initial inbred lines. Comparisons among generations allow investigating the dynamics of the response to selection in a changing environment. Comparisons between Early and Late families allow investigating the genotype-phenotype map.

Early and Late progenitors from generation G18 will be used to perform in-depth characterization of plants growth and development (Task 1). Integration of different scales (from the genetic level to the whole plant growth dynamics) will make use of both partner's expertise and strong investment in statistical modelling.

Data will serve to calibrate a plant growth model that couples development, phenology and metabolism (Task 2) to better understand how the environment can modulate maize life-cycle, as well as to decipher between genetic and plastic bases for life-cycle shifts. An evaluation trial of all plant material of the selection experiment will help to monitor and modelize genetic and phenotypic changes that occurred during the response to selection, and to better understand genotype-phenotype relationships. Again, the project will benefit from both practical (phenotyping) and theoretical (quantitative and population genetics) advances from the partners, as well as from a strong input from mathematics.

Finally we will use climatic data from the last 20 years, along with the observed response to selection, to describe links between environment and the dynamics of adaptation. Using Lepidoptera stem borers as a model system, we will also analyse how plant phenology shifts interfere with pathogen life-cycles.

Results

==> The researcher explains the project and its RESULTS in VIDEO (LabEx BASC scientific days, January 2021)

Publications

> Vidal, T., Aissaoui, H., Rehali, S., and Andrieu, B. (2021). Two maize cultivars of contrasting leaf size show different leaf elongation rates with identical patterns of extension dynamics and coordination. Aob Plants https://doi.org/10.1093/aobpla

> Desbiez-Piat A., Le Rouzic A., Tenaillon M.I., Dillmann C. (2020) Interplay between high-drift and high-selection limits the genetic load in small selfing maize populations. bioRxiv: https://doi.org/10.1101/2020.12.22.423930  

> I. Sanané, J. Legrand, C. Dillmann, F. Marion-Poll (2020) A semi-automated design for high-throughput Lepidoptera larvae feeding bioassays. https://doi.org/10.1101/2020.08.02.232256

> Tenaillon M.I., Sedikki K., Mollion M., Le Guilloux M., Marchadier, E., Ressayre A., Dillmann C. (2019). Transcriptomic response to divergent selection for flowering time in maize reveals convergence and key players of the underlying gene regulatory network. BioRxiv, 461947, ver. 5. Peer-reviewed and recommended by PCI Evolutionary Biology (Tanja Pyhäjärvi (2019) Early and late flowering gene expression patterns in maize. Peer Community in Evolutionary Biology, 100071. 10.24072/pci.evolbiol.100071) https://doi.org/10.1101/461947

> Vidal T, Andrieu B., 2019. Contrasting phenotypes emerging from stable rules: A model based on self-regulated control loops captures the dynamics of shoot extension in contrasting maize phenotypes. Ann Bot. 2019 Oct 19. pii: mcz168. https://doi.org/10.1093/aob/mcz168

> Vidal, T., Dillmann, C., Andrieu, B., 2018. A coordination model captures the dynamics of organ extension in contrasted maize phenotypes, in: 2018 6th International Symposium on Plant Growth Modeling, Simulation, Visualization and Applications (PMA). IEEE, pp. 126–133. https://doi.org/10.1109/PMA.2018.8611569