MERCI

Partners

- Institut Jean-Pierre Bourgin (IJPB)
Team: Meiosis & Recombination
- UMR Quantitative Genetics and Evolution - Le Moulon (GQE-Le Moulon)
Team: Recombination of Alleles in Meiosis: Determinism, Applications and Modelling 
- Consortium of seed companies : KWS, SECOBRA and MARS

Abstract of the project

Meiotic recombination is at the heart of the life cycle of all sexual eukaryotes; it is required to produce balanced gametes and therefore is essential to fertility. Meiotic recombination is also crucial for evolution and plant breeding as it allows the reshuffling of genetic information between individuals through the formation of crossovers (COs). However, the low overall amount of COs and the existence of large genomic regions almost completely devoid of any COs are still limiting factors for crop improvement. To overcome these constraints, we first sought to increase CO rate in oilseed rape by knocking-out the genes that encode FIGL1, a negative regulator of CO in Arabidopsis thaliana. We have accumulated and are accumulating a strong body of evidence that disruption of FIGL1 leads to genome instability in this polyploid crop. Knockout mutants show chromosomal fragmentation during meiosis and the progeny of plants with a double heterozygous combination of mutant and WT alleles show evidence of segmental/chromosomal loss and duplication. Next, we ran a new forward genetic screen to identify genes controlling CO distribution. Combining a novel population of highly mutagenized plants and a sensitive phenotypic screen, we have identified a couple of new meiotic recombination genes that we are still characterizing. We also analysed the impact of increased CO number on selection response in breeding programs through both computer modeling and proof of concept selection cycles. We showed that unleashing CO leads to shorter introgressions (but a higher proportion of background donor fragments across the genome) in backcross programs and to higher gains in programs aimed at improving complex traits through genomic selection. Finally, we performed five cycles of recurrent selection on a population of hyper-recombinant Arabidopsis mutants, and corresponding WT controls, to measure directly the effect of increased recombination on genetic progress. Altogether, the project has provided knowledge, tools and know-hows to better rationalise the use of meiotic recombination in plant breeding programmes; it also helped us to strengthen links with plant breeding companies, moving from information exchange to co-construction of projects.

Publications:

Blary, A., Jenczewski, E. (2018). Manipulation of crossover frequency and distribution for plant breeding. Theoretical and Applied Genetics, 1-18. , DOI : 10.1007/s00122-018-3240-1

Capilla-Perez L, Solier V, Portemer V, Chambon A, Hurel A, Guillebaux A, Vezon D, Cromer L, Grelon M, Mercier R. (2018) The HEM Lines: A New Library of Homozygous Arabidopsis thaliana EMS Mutants and its Potential to Detect Meiotic Phenotypes. Front Plant Sci 2018; 9:1339.

Christophorou N, She W, Long J, Hurel A, Beaubiat S, Idir Y, Tagliaro-Jahns M, Chambon A, Solier V, Vezon D, Grelon M, Feng X, Bouché N, Mézard C. (2020) AXR1 affects DNA methylation independently of its role in regulating meiotic crossover localization. PLoS Genet. 16(6):e1008894

Jenczewski E. (2020) La régulation génétique du taux de recombinaison chez les plantes. Le sélectionneur Français. 11-21

Mercier R. (2020) Manipuler la méiose pour augmenter globalement ou abolir la recombinaison. Le sélectionneur Français. 43-48

Pfalz M., Gonzalo A., Christophorou N., Blary A., Berard A., Bessoltane N., Montes E., Jaffrelo L., Poncet C., Le Paslier M.C., Nesi N., Charif D. and E. Jenczewski (2020) Identifying and isolating of meiotic mutants in polyploid Brassica crops. Methods Mol Biol, 2061:303-318

Tourrette E., Bernardo R., Falque M., Martin OC. (2019) Assessing by Modeling the Consequences of Increased Recombination in Recurrent Selection of Oryza sativa and Brassica rapa. G3, 12 (9) 4169-4181

Tourrette E., Falque M., Martin OC. (2020) Augmenter la recombinaison dans les programmes de sélection: promesses et points de vigilance. Le sélectionneur Français. 71-81

Tourrette E., Falque M., Martin OC. (2021) Enhancing backcross programs through increased recombination. Genet Sel Evol, 1 (53) 25

Tourrette E., Ph Dissertation, Unleashing genetic diversity in breeding by increasing recombination: an in silico study; defended on November 25, 2019

Vidal A., Gauthier F., Rodrigez W., Guiglielmoni N., Leroux D., Chevrolier N., Jasson S., Tourrette E., Martin OC., Falque M. (2022) SeSAM: software for automatic construction of order-robust linkage maps. BMC Bioinformatics, 1 (23) 499

Communications in conferences:

Capilla-Perez L., Solier V., Portemer V., Chambon A., Hurel A., Christophorou N., Vezon D., Grelon M., Mercier R.. Description of new Arabidopsis thaliana mutants with defects in crossover number and distribution. EMBO Meiosis Meeting 2019 (poster)

Tourrette E., Falque M., Martin O. C. Unleashing genetic diversity by increased meiotic recombination: an in silico benchmark. DuPont Plant Sciences Symposia series: "Genetic Diversity: a Cornerstone of Plant Breeding", Paris (France), September 2017 (poster)

Tourrette E., Falque M., Martin O. C. Unleashing genetic diversity by increased meiotic recombination: an in silico benchmark. Plant and Animal Genome Conference, San Diego (USA), January 2018 (poster)

Tourrette E., Falque M., Martin O. C. Unleashing genetic diversity by increased meiotic recombination: an in silico benchmark. Maize Meeting, Saint-Malo (France), March 2018 (poster)

Tourrette E., Falque M., Martin O. C. Unleashing genetic diversity by increased meiotic recombination: an in silico benchmark. Eucarpia Biometrics, Ghent (Belgium), September 2018 (talk)

Tourrette E., Falque M., Martin O. C. Using increased recombination to accelerate genomic selection programs. Eucarpia Maize and Sorghum, Freising (Germany), October 2019 (talk)