Genomic and transcriptome analyses reveal the molecular basis for erucic acid biosynthesis in seeds of rapeseed (Brassica napus)

Abstract

Abstract Erucic acid (EA) is an important quality trait in rapeseed with low EA content (LEAC) oil being recognized as a healthy edible oil and high EA oil holding industrial value. Despite its importance, the consequences of intensive selection for LEAC genotype and the genes associated with EA regulation remain largely unknown. Here, we employed selective signal analyses (SSA), genome-wide association study (GWAS), and transcriptome analyses to enhance our understanding on the molecular base of EA regulation. Our investigation revealed the genetic footprints resulting from LEAC selection in germplasm populations, highlighting genetic regions for enriching diversity. Through GWAS, we identified 654 genes, including enzymes involved in the fatty acid biosynthesis and various transcription factors, that significantly associated with EAC variation. By combining SSA, GWAS, and transcriptome analyses, a subset of 23 genes that have a significant impact on EAC in seeds is recommended. Example genes such as Fatty Acid Elongation 1 and Methylcrotonoyl-CoA Carboxylase Beta Chain were selected to illustrate the SNP distributions, haplotypes for EAC phenotypes and the development of molecular marker to distinguish LEAC and HEAC genotypes. These findings provide insights into the mechanism of EA regulation and shed light on the manipulation of the genes regulating EA biosynthesis.