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Meiotic recombination is essential for fertility of species and is also crucial for plant breeding because it allows, through the formation of crossovers, to reshuffle genetic material between individuals and between species. Major international efforts have been made to characterize the genes involved in meiotic recombination using diploid Arabidopsis thaliana as model. Therefore, much of this work has disregarded the consequences of polyploidy, one of the key features of crop plant genomes, on meiotic recombination. Essential questions thus remain unsolved such as how is meiotic recombination regulated in polyploid (crop) species. This project focuses on the positional cloning of a gene involved in the regulation of homoeologous pairing in wheat, Ph2. Two strategies are conducted in parallel: (1) the first one aims to understand the impact of the mutation of MSH7, a gene that is currently considered as one of the best candidate for Ph2. This work is based on the identification of mutants for the 3DS copy and crosses with rye in order to observe the meiotic behaviour of the haploid wheat/rye hybrids. (2) The second strategy aims to reduce the interval carrying the Ph2 gene to a few megabases in order to decrease the number of candidate genes. This relies on the development of a set of deletion lines characterized using SNP markers. The new anchored and annotated sequence of the wheat genome will be used for precise determination of the genes located in each deletion. Candidate genes for Ph2 will be identified by further analyses of their expression level during meiosis and their potential involvement in meiosis deduced from literature studies. The expected outcomes of this project is to pave the way to broaden the genetic variation that is available to wheat breeders and open the road to the creation of new crop varieties resistant to biotic and abiotic stresses to face the challenge of improving wheat production in a context of a sustainable agriculture using less fertilizers, water and pesticides.
I am a young scientist interested in the molecular mechanisms of recombination in Plants. During my PhD in the "Genetic, Reproduction and Development" laboratory in Clermont-Ferrand, I worked on the roles of key homologous recombination effectors in DNA double strand break repair. We highlighted unexpected and essential roles of these proteins in maintaining Arabidopsis genome stability. To extend my research on homologous recombination mechanisms to meiosis, I then joined the "Genetic and Epigenetic Inheritance in Plant" laboratory at Cambridge University (UK) in 2014. My main achievement was the development of highly recombining Arabidopsis plants by simultaneously increasing both class I and class II crossover pathways. As low level of recombination limits plant breeding, this strategy has an exciting potential to drive massive crossover elevations in crop genomes and accelerate breeding. Since March 2018, I have joined the "Genetic, Diversity and Ecophysiology of Cereales" laboratory (INRA, ClermontFerrand) as an AgreenSkills+ fellowship. I am currently developing a research project aiming at deciphering the homoeologous recombination in the wildly cultivated bread wheat in order to help breeders introducing new original and performing alleles originating from wheat wild relatives and consequently, facilitate plant breeding programs.
Serra H, Lambing C, Griffin CH et al., 2018. Massive crossover elevation via combination of HEI10 and recq4a recq4b during Arabidopsis meiosis. Proc. Natl. Acad. Sci. U.S.A 115(10):2437-2442.
Choi K, Yelina N, Serra H, Henderson I, 2017. Quantification and sequencing of crossover recombinant molecules from Arabidopsis pollen DNA. Methods in Molecular Biology 1551:23-57.
Richter K, Serra H, White C, Jeske H, 2016. The recombination mediator RAD51D promotes geminiviral infection. Virology 493, 113-127.
Choi K*, Reinhard C*, Serra H et al., 2016. Recombination rate heterogeneity within Arabidopsis disease resistance genes. PLoS Genetics 12(7): e1006179. Doi: 10.1371/ journal.pgen.1006179.
Serra H, Da Ines O, Degroote F, Gallego ME, White C, 2013. Roles of XRCC2, RAD51B and RAD51D in RAD51independent SSA recombination. PLoS Genetics 9(11): e1003971. Doi: 10.1371/journal.pgen.1003971.