Welcome to the ISHS Brassica 2012 Symposium

Session A-3
EXPLORING THE BRASSICA B GENOME AT THE WHOLE GENOME SEQUENCE
LEVEL
Parkin I. 1 *, Koh C. 2 , Clarke C. 2 , Navabi Z.H. 1 , Sharpe A. 2
1 Agriculture and Agri-Food Canada, 107 Science Place, Saskatoon, S7N0X2, Canada;
2 National Research Council of Canada, 110 Gymnasium Place, Saskatoon, S7N0W9, Canada.
E-mail: isobel.Parkin@AGR.GC.CA
Progenitors of the three Brassica diploid species, B. rapa (A genome), B. oleracea (C genome and
B. nigra (B genome) form the apices of U’s triangle, and together with the amphidiploid species
formed from their pairwise hybridization, encompass all economically important Crucifereae crops.
Brassica nigra although perhaps the oldest recorded Brassica species, with references from 3000
BC, has been neglected, especially with respect to breeding improvements, largely due to its use as
a mustard crop being usurped by B. juncea, since B. nigra could not be easily mechanically
harvested. As well as representing effectively half the genome of the important mustard crop B.
juncea, the B genome harbours favourable alleles for a number of important agronomic traits,
specifically resistance to abiotic and biotic stresses. Although closely related at the gene sequence
level there has been limited success in transferring useful traits from the B genome into the A or C,
the reasons for which are still debated. We have developed a whole genome sequence for B. nigra,
combining the high sequence coverage of Illumina next generation sequencing (NGS) with the
improved scaffolding offered by large insert Roche 454 mate-pair libraries. The current assembly
covers 452 Mb, an estimated 71% of the predicted 632 Mb genome and has been linked to the
genetic map with high density sequence tag mapping. We will present the results of comparative
genome analysis between the three Brassica diploid genomes, which offers insights into the unique
nature of the Brassica B genome and its potential for furthering our knowledge of Brassica genome
evolution.
6 th International Symposium on Brassica and 18 th Crucifer Genetic Workshop - Catania (Italy) 12 - 16 November 2012
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