Molecular Cloning and Expression Analysis of a Delta 6-Fatty Acid Desaturase Gene from Rhizopus stolonifer Strain YF6 Which Can Accumulate High Levels of Gamma-Linolenic Acid

The delta 6-desaturase gene was cloned from Rhizopus stolonifer, which could accumulate up to 49% of gamma-linolenic acid (GLA, C18:3 Delta(6,9,12)) to the total fatty acids. The cloned DNA contains a 1,380 bp open reading frame encoding a protein of 460 amino acids, which showed high similarity to those of fungal delta 6-desaturases with three conserved histidine-rich motifs and HPGG motif. Notably, this deduced sequence had a shorter C-terminus. Results demonstrated that the cDNA sequence exhibited delta 6-desaturase activity by accumulation of about 22.4% of GLA to the total fatty acids in the recombinant Pichia pastoris strain GS115.