Genome Wide Approach for Nutrition Breeding in Brassica Species

Genomic study and nutrition research have been developed in parallel for a long time. Plant nutriomics is a new frontier in plant biology, involving genomic, transcriptomic, proteomic and metabolomics in a network. Brassica species constitutes one of the world’s most diverse and economically important plant groups with variations of functional compounds such as glucosinolates, β-carotene, lutein, phenolic acids, flavonoids, etc. Since the draft sequencing of the Chinese cabbage genome was completed, functional genomics research has been rapidly expanded to understand metabolic pathways and regulatory mechanisms of related genes. Thus, we combined a genome wide comparative study, QTL mapping and large scale microarray analysis to discover their metabolic pathways and regulatory mechanisms of related genes. QTL analysis for glucosinolate accumulation in B. rapa leaves and seeds was carried out by using a CRF_3/4 population, derived from a cross between “Chiifu” and rapid cycling type “RCBr” which showed significant difference in glucosinolate content. Through synteny genomic comparison to A. thaliana, candidate genes and single nucleotide polymorphisms (SNPs) between parental lines were identified from whole genome re-sequenced data by NGS (Next Generation Sequencing). In addition, for carotenoids, 57 full length CDs were identified from Brassica. These genes were also identified in in-home developed 50K microarray dataset for Chiifu and RCBr, and their levels of differential expressions were checked. Moreover, numerous collected Brassica accessions and germplasms supported by Korea Brassica Genome Resource Bank were also used for important functional compound analysis. With the accessions and microspore culture, we have developed doubled haploid lines and finally selected inbred lines containing high concentration of specific compounds, which paves the way for the gene association study and evolutionary study in near future.