Crossovers get a boost in [i]Brassica[/i] allotriploid and allotetraploid hybrids
2010
Leflon, Martine | Grandont, Laurie | Eber, Frederique | Huteau, Virginie | Coriton, Olivier | Chelysheva, Liudmila | Jenczewski, Eric | Chèvre, Anne-Marie | Amélioration des Plantes et Biotechnologies Végétales (APBV) ; Institut National de la Recherche Agronomique (INRA)-Université de Rennes (UR)-AGROCAMPUS OUEST | Institut Jean-Pierre Bourgin (IJPB) ; Institut National de la Recherche Agronomique (INRA)-AgroParisTech
L'article original est publié par The American Society of Plant Biologists
Afficher plus [+] Moins [-]anglais. Meiotic crossovers are necessary to generate balanced gametes and to increase genetic diversity. Even if crossover number is usually constrained, recent results suggest that manipulating karyotype composition could be a new way to increase rossover frequency in plants. In this study, we explored this hypothesis by analyzing the extent of crossover variation in a set of related diploid AA, allotriploid AAC, and allotetraploid AACC Brassica hybrids. We first used cytogenetic methods to describe the meiotic behavior of the different hybrids. We then combined a cytogenetic estimation of class I crossovers in the entire genome by immunolocalization of a key protein, MutL Homolog1, which forms distinct foci on meiotic chromosomes, with genetic analyses to specifically compare crossover rates between one pair of chromosomes in the different hybrids. Our results showed that the number of crossovers in the allotriploid AAC hybrid was higher than in the diploid AA hybrid. Accordingly, the allotetraploid AACC hybrid showed an intermediate behavior. We demonstrated that this increase was related to hybrid karyotype composition (diploid versus allotriploid versus allotetraploid) and that interference was maintained in the AAC hybrids. These results could provide another efficient way to manipulate recombination in traditional breeding and genetic studies.
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