摘要
Brassica rapa comprises several important cultivated vegetables and oil crops.Current reference genome assemblies of Brassica rapa are quite fragmented and not highly contiguous,thereby limiting extensive genetic and genomic analyses.Here,we report an improved assembly of the B.rapa genome(v3.0)using single-molecule sequencing,optical mapping,and chromosome conformation capture technologies(Hi-C).Relative to the previous reference genomes,our assembly features a contig N50 size of 1.45 Mb,representing a~30-fold improvement.We also identified a new event that occurred in the B.rapa genome~1.2 million years ago,when a long terminal repeat retrotransposon(LTR-RT)expanded.Further analysis refined the relationship of genome blocks and accurately located the centromeres in the B.rapa genome.The B.rapa genome v3.0 will serve as an important community resource for future genetic and genomic studies in B.rapa.This resource will facilitate breeding efforts in B.rapa,as well as comparative genomic analysis with other Brassica species.
基金
This work is supported by the National Natural Science Foundation of China(NSFC grants 31630068 and 31722048)
the National Program on Key Research Project(2016YFD0100307)
the Science and Technology Innovation Program of the Chinese Academy of Agricultural Sciences,the Key Laboratory of Biology and Genetic Improvement of Horticultural Crops,Ministry of Agriculture,P.R.China,the Prospect of Shandong Seed Project,China(Shandong Gov.(2015)Reference No.212)
the China Scholarship Council(CSC)(No.201503250081).
