Studies on the Function of Delta 6-Fatty Acid Desaturase for γ-Linolenic Acid Synthesis from Mucor circinelloides

Abstract:

γ-linolenic acid（GLA） that is an essential polyunsaturated fatty acid（PUFA） plays a vital role in many metabolic processes. Most related studies showed that delta 6-fatty acid desaturase（FAD6） was an important rate-limiting enzyme for the synthesis of γ-linolenic acid from Mucor circinelloides. However，it has not been reported whether the delta 6- fatty acid desaturase is the only pathway to produce γ-linolenic. In this work，we constructed M. circinelloides EIM10 sp.FAD6 knockout vector pUMCD6-HmB on the basis of pUC18 to study the function of FAD6. The homologous sequences of 5' promoter and 3' terminator of FAD combined with hygromycin B resistant gene used as the selective marker were connected as the knockout fragment. Then the vector pUMCD6-HmB was transformed into the prepared protoplast of M. circinelloides EIM10 sp. The results showed that FAD6 gene was successfully disrupted and GLA accumulation of the mutant disrupted in FAD6 decrease about 50% compared to the wild type. It can be concluded that FAD6 was essential for GLA production in M. circinelloides but there is probably other ways to accumulate GLA in M. Circinelloides.