Chromosome level assembly of five Brassica rapa and oleracea accessions expand the resistance genes reservoir.

Brassica rapa and B. oleracea are two diploid crops of agronomic importance, which display important phenotypic variation. They are the diploid progenitors of B. napus (oilseed rape), another major crop, which suffers from low genetic diversity. For that reason, B. rapa and B. oleracea are often used to introgress traits of interest into B. napus. In this study we assembled, at the chromosome level, the genomes of three B. oleracea accessions (including a wild type), and largely improved the genome assemblies of two B. rapa genotypes using Oxford Nanopore Technologies and Illumina sequencing. A total of 91.9 to 98.7% of the assembled sequences were anchored to pseudochromosomes. We also produced RNA-Seq data from different organs (flower bud, leaf, root and stem) for gene annotations. Overall, 94.97 to 99.49% of the predicted genes are on pseudomolecules. Finally, we also predicted their resistance gene analogs, including ones unique to each assembly. These five chromosome level assemblies represent a crucial resource to expand the known reservoir of disease resistance genes.