Sequence Analysis of a Plastidial Omega-3 Desaturase Gene from Brassica juncea^†

A genomic clone (λg₂) encoding a plastidial omega-3 desaturase has been isolated from a genomic library of Brassica juncea cv Pusa Bold and sequenced after subcloning. A continuous stretch of 3866 bp of the clone sequenced showed homology with omega-3 desaturase from other plant sources but maximum homology was with that of a plastidial omega-3 fad 7 gene. This sequence designated as Bjgfad7 includes 1381 bp 5′ untranslated region, 273 bp 3* untranslated region along with an open reading frame of 1290 bp interrupted by 7 introns. The 5′ untranslated region contains putative cis elements responsible for seed specificity, light responsive and stress-inducible expression besides minimal promoter elements.