Meiosis in Brassica: From Model to Crop

During meiosis haploid gametes are generated from diploid germ cells thus halving the chromosome number and concomitantly recombining the parental chromosomes thereby generating novel allelic combinations which can be exploited in breeding programmes.

Arabidopsis thaliana has been for many years the plant model for investigating meiosis. We now wish to use this information to modify recombination in the closely related and agriculturally important Brassica crops, such as B. rapa (e.g. Chinese cabbage), B. oleracea (e.g. cabbage, broccoli, cauliflower) and B. napus (e.g. rapeseed). In addition, Brassica is potentially an excellent system for meiosis research since through possessing relatively large anthers it provides the opportunity to investigate meiotic protein complexes using proteomic methods, something that is challenging in Arabidopsis. Also having large chromosomes it is ideally suited for studying the coordination of recombination in relation to chromosome remodelling which is emerging as crucial for the controlled formation of crossovers.

The aim of this project is to take advantage of a B. rapa TILLING population developed at John Innes Centre (UK) to identify mutations in meiotic genes that have been shown from studies in Arabidopsis to play key roles in meiotic recombination. This will enable modification of recombination in Brassica and provide a useful resource for refining our analysis of meiotic protein complexes and chromosome dynamics. Several lines carrying mutations in meiotic genes including ASY1 and PCH2 which are required for the controlled formation of genetic crossovers have been identified. Progress in the analysis of these lines will be presented.