International Journal of Plant Genomics 
Volume 2008 (2008), Article ID 582837, 9 pages
doi:10.1155/2008/582837
Review Article

Progress in Understanding and Sequencing the Genome of Brassica rapa

Chang Pyo Hong,1 Soo-Jin Kwon,2 Jung Sun Kim,2 Tae-Jin Yang,3 Beom-Seok Park,2 and Yong Pyo Lim1

 1Department of Horticulture, College of Agriculture and Life Science, Chungnam National University, Daejeon 305764, South Korea
2Brassica Genomics Team, National Institute of Agricultural Biotechnology (NIAB), Rural Development Administration (RDA), Suwon 441707, South Korea
3Department of Plant Science, College of Agriculture and Life Sciences, Seoul National University, Seoul 151921, South Korea
Received 13 June 2007; Accepted 21 November 2007

Recommended by Yunbi Xu

Abstract

Brassica rapa, which is closely related to Arabidopsis thaliana, is an important crop and a model plant for studying genome evolution via polyploidization. We report the current understanding of the genome structure of B. rapa and efforts for the whole-genome sequencing of the species. The tribe Brassicaceae, which comprises ca. 240 species, descended from a common hexaploid ancestor with a basic genome similar to that of Arabidopsis. Chromosome rearrangements, including fusions and/or fissions, resulted in the present-day “diploid” Brassica species with variation in chromosome number and phenotype. Triplicated genomic segments of B. rapa are collinear to those of A. thaliana with InDels. The genome triplication has led to an approximately 1.7-fold increase in the B. rapa gene number compared to that of A. thaliana. Repetitive DNA of B. rapa has also been extensively amplified and has diverged from that of A. thaliana. For its whole-genome sequencing, the Brassica rapa Genome Sequencing Project (BrGSP) consortium has developed suitable genomic resources and constructed genetic and physical maps. Ten chromosomes of B. rapa are being allocated to BrGSP consortium participants, and each chromosome will be sequenced by a BAC-by-BAC approach. Genome sequencing of B. rapa will offer a new perspective for plant biology and evolution in the context of polyploidization.