ON THE WAY TO THE IDENTIFICATION OF A DOWNY MILDEW RESISTANCE GENE IN BRASSICA OLERACEA L.
We have recently mapped the dominant and monogenically inherited downy mildew resistance locus Pp523 to the chromosome C8 of Brassica oleracea L. and constructed a physical-map of the genomic region of this locus. Presently, we are constructing a BAC genomic library of a downy mildew resistant S4 line derived from the broccoli accession originally found to harbor the Pp523 locus and using STS markers derived from the previously constructed physical map in order to identify a contig of BAC clones which sequencing could allow the isolation and cloning of this resistance locus. The new BAC library contains 17280 clones with an average insert size of 125 Kbp, which represent approximately 3.5 equivalents of the broccoli genome. To date, 18 clones from this new library were selected and assembled in a contig (with two small gaps) that covers the major part of the previously physically mapped region. The overlapping between BAC clones has been identified by PCR and confirmed by sequencing of the PCR products. The precise positioning of BAC clones in the genome has been made possible through the alignment of the BAC-end sequences with the genomic sequences of B. oleracea available at the Brassica database (BRAD).
Carlier, J., Alabaça, C., Rodrigues , C. and Leitão, J. (2013). ON THE WAY TO THE IDENTIFICATION OF A DOWNY MILDEW RESISTANCE GENE IN BRASSICA OLERACEA L.. Acta Hortic. 1005, 233-237
Hyaloperonospora, Pp523, BAC library, BAC contig, minimal tiling path