TOWARDS ANALYSIS OF GENE EXPRESSION IN BRASSICAS

Brassica and Oilseeds Research Department, John Innes Centre, Norwich Research Park, Norwich, NR2 7UH. U.K.

The cultivated Brassica species, including B.napus (rapeseed) and B. oleracea (cabbage, broccoli) are the important group of crops most closely related to the model dicot Arabidopsis thaliana. Genetic mapping studies have indicated that the genomes of the diploid Brassica species resemble a triplicated and multiply rearranged Arabidopsis-like genome (Largercrantz, Genetics 150: 1217-1228, 1998). Hybridisation-based physical mapping studies have confirmed the underlying triplicated structure of the diploid Brassica genome, but with a substantial loss of microsynteny (C. O'Neill and I. Bancroft, to be reported at this meeting). A key question to ask is; how is gene expression controlled within such a redundant genome? Using degenerate PCR on BAC clone contigs of the replicated regions in Brassica oleracea, we obtained PCR products from 5 complete sets of replicated genes. Sequencing of these products has enabled us to establish the relationship between the Brassica genes and their Arabidopsis orthologues. We are also undertaking transcription studies to assay the relative expression of every member of each gene family in different tissues. The results of our sequence analysis and initial gene expression studies will be presented.