Zero erucic acid trait of rapeseed (Brassica napus L.) results from a deletion of four base pairs in the fatty acid elongase 1 gene

• DOI: 10.1007/s00122-007-0685-z
• Publication Date: 2007-12-12T09:19:47Z
• Authors: Gang Wu; Yuhua Wu; Ling Xiao; Xiaodan Li; Changming Lu
• Keywords: 2. Zero hunger; Erucic Acids; 0303 health sciences; Sequence Homology, Amino Acid; Fatty Acid Elongases; Reverse Transcriptase Polymerase Chain Reaction; Blotting, Western; Brassica napus; Molecular Sequence Data; Saccharomyces cerevisiae; Lipids; 03 medical and health sciences; Acetyltransferases; Gene Expression Regulation, Plant; RNA, Plant; Seeds; Protein Isoforms; Amino Acid Sequence; RNA, Messenger; Cloning, Molecular; Sequence Deletion

The fatty acid elongase 1 (FAE1) gene is a key gene in the erucic acid biosynthesis in rapeseed. The complete coding sequences of the FAE1 gene were isolated separately from eight high and zero erucic acid rapeseed cultivars (Brassica napus L.). A four base pair deletion between T1366 and G1369 in the FAE1 gene was found in a number of the cultivars, which leads to a frameshift mutation and a premature stop of the translation after the 466th amino acid residue. This deletion was predominantly found in the C-genome and rarely in the A-genome of B. napus. Expression of the gene isoforms with the four base pair deletion in a yeast system generated truncated proteins with no enzymatic activity and could not produce very long chain fatty acids as the control with an intact FAE1 gene did in yeast cells. In the developing rape seeds the FAE1 gene isoforms with the four base pair deletion were transcribed normally but failed to translate proteins to form a functional complex. The four base pair deletion proved to be a mutation responsible for the low erucic acid trait in rapeseed and independent from the point mutation reported by Han et al. (Plant Mol Biol 46:229-239, 2001).