Cloning, Sequencing and Characterization of FAE1 Genes of Brassica juncea cv Pusa Bold and the Mutant fae1 of B. rapa cv Tobin

Level of erucic acid (22:1), the major storage fatty acid of oil seed Brassica, is controlled by the activity of the Fatty Acid Elongation1 (FAE1) gene. Southern hybridization revealed the presence of two FAE1 genes in B. juncea. The two FAE1 genes of B. juncea and the mutant fae1 of B. rapa cv Tobin were isolated from genomic libraries of the respective species and sequenced. The two BjFAE1 gene sequences shared more than 98% homology and contained ORF capable of coding for 509/510 amino acid polypeptides. One of the FAE1 genes of B. juncea was found to be nearly identical (99.6%) to the mutant formof B. rapa suggesting its origin from the later species. Comparison of the sequences generated with one another and with other FAE1 sequences in the database revealed that substitution of C₂₃₃ (cysteine) with G (glycine) might be responsible for the loss of enzyme activity in B. rapa cv Tobin.