Michelle Rönspies

Bayer Pharmaceuticals PhD Award
Redirecting meiotic recombination in plants by CRISPR/Cas-mediated chromosome engineering

Michelle Rönspies

/Karlsruhe [DE]

One of the main goals of plant breeding is to combine multiple attractive traits in one single cultivar. At the moment, plant breeders rely on random crossovers (COs) between parental homologous chromosomes to create favorable genetic linkages. Therefore, it would be of great interest for breeders to be able to lock these linkages in a targeted manner. Using CRISPR/Cas-mediated chromosome engineering, it is possible to induce large-scale chromosomal rearrangements (CRs) in plants. Naturally, CRs suppress meiotic COs in the rearranged area. Based on this premise, the aim of this work was to analyze the effects of a CRISPR/Cas-induced 17 Mb inversion, corresponding to nine-tenths of chromosome 2 and one-eighth of the genome of Arabidopsis thaliana, to investigate whether the recombination landscape can be manipulated at the chromosomal level by CO suppression. In single-nucleotide polymorphism marker analysis, a massive reduction of COs was detected within the inverted region. By analyzing the effects of a 13 Mb chromosome arm inversion on chromosome 3, it was shown that the manipulation of meiotic recombination can be induced independently of inversion size and position. Therefore, chromosome engineering could be a valuable tool for plant breeders in protecting genetic linkages of any size from recombination. Additionally, the foundations for changing the genome structure of plants in an even more global way, e.g. by changing chromosome numbers, were laid in this work.

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