Bread wheat (Triticum aestivum) improvement is a necessity to face the challenge of feeding the world population in the context of a sustainable agriculture using less fertilizers, pesticides and water and taking into account global warming. A strategy to overcome this challenge is to better manage and exploit the extensive and underexploited cereal genetic resources. Introduction of original alleles or genes occurs through meiotic recombination (or crossover; CO), a highly conserved process at the heart of the life cycle and common to most sexual eukaryotes. A major bottleneck in wheat comes from variation of CO rates in different regions of the genome in which 90% of COs occur in only 40% of the genome - with at least 30% of wheat genes lying in recombination poor regions. There is therefore a need to improve both CO rate and CO location to develop new and resilient wheat varieties. In this project, we propose to knock-out or to overexpress one, two or the three homoeologous copies of TaRecq4, TaAsy1 and TaHei10 using a CRISPR-Cas9 approach or the dCas9-SunTag system, expressed under the DMC1 promoter, on Fielder. We will finally evaluate the recombination phenotype using a combination of cytogenetic and genomic approaches to determine if homologous and homoeologous recombination are different in the knock-out and over-expressing lines.
