Unravelling the Genetic Control of Tocopherol Biosynthesis in Rapeseed (Brassica napus L.) using Associative Transcriptomics

Rapeseed (Brassica napus L.) is one of the most important oil crops grown worldwide. Rapeseed oil contains high amounts of tocopherols, lipid-soluble antioxidants, which have important structural and protective functions in plants, and have a significant impact on oil-stabilizing activity. Tocopherols belong to the group of vitamin E compounds, and are an important source of essential vitamin E in human and livestock diets. In this study we used Associative Transcriptomics to determine the genetic architecture of tocopherol content in rapeseed oil using 355,536 SNPs and 53,889 gene expression markers (GEMs) in a new diversity panel of 383 accessions of B. napus. The seed tocopherol content across the panel was normally distributed and ranged from 196.3 to 445.5 mg.kg^-1 for total tocopherol, 56.6 to 229.3 mg.kg^-1 for alpha-tocopherol, 78 to 347 mg.kg^-1 for gamma-tocopherol, and 1.3 to 14 mg.kg^- for delta-tocopherol. SNP and GEM association analysis revealed strong associations in several regions of the A and C genomes for different tocopherol traits, providing valuable genetic markers for use in future breeding programmes to select for different tocopherol profiles.