Identification Of Candidate Functional Genes By Combining RNA-seq With QTL Mapping In Brassica Napus

Brassica napus is one of the most important oil crops in China,and it is also a potential source of bulk feed protein,there is of great significance to the development of national economy.Increasing yield and improving quality are always the main objectives in the genetics and breeding of rape.The flowering of Brassica napus is a turning point from vegetative growth to reproductive growth;up to now,there have reported many studies on the flowering-related functional genes of Brassica napus.Using Chinese rape variety 'Gaoyou' and German rape variety 'Sollux' as parents,and combination of RNA-seq and QTL mapping,this study carried out fast screening and identification of flowering-related candidate functional genes in rape.The transcriptional sequence data of rape buds was analyzed by RNA-seq technique,704 differentially expressed genes between two parents were detected,nine of which were orthologous with the flowering genes(FLC?FY?LHP?PFT1?SKB1?TFL1?VGT1?VIN)of Arabidopsis thaliana;The homologous gene of FLC was located in region of the major flowering QTL.Map-based cloning found there was no significant difference in the FLC DNA sequence between two parents,but five distinct differences in the promoter region.We also conducted fine-mapping on the major-effect QTL(qFTC6)for the flowering trait,the interval size of the QTL was narrowed down from physical distance of 1.5Mb to 342Kb,and the FT homologous gene was located in this QTL region by RNA-seq analysis.