FAD2 gene mutation and fatty acid analyses in fad2.

(A) Intron-exon organization of the Arabidopsis FAD2 gene (not to scale). The mutation site was indicated. Solid boxes and lines represent exons and introns, respectively. (B) The amino acid mutation site in the predicted topology of FAD2 protein. Three His boxes (black ellipses) oriented on the cytosolic side of the membrane coordinate two iron atoms (gray circles) at the active site of the protein. The mutation site was indicated (from A104 to T104). (C) Fatty acid analyses of Col-0, fad2 and fad2 mutant complemented with the functional wild-type FAD2 or the mutated FAD2Δ gene. Col-0, wild-type Columbia; fad2, FAD2 mutant; fad2/FAD2-1 and fad2/FAD2-2, two transgenic fad2 lines complemented with the functional Col-0 FAD2 gene; fad2/FAD2Δ-1 and fad2/FAD2Δ-2, two transgenic fad2 lines complemented with the mutated FAD2Δ gene. Results are presented as means and standard errors from three independent experiments. ** indicates significant difference in comparison to Col-0 at P<0.01 (Student's t-test).