γ-氨基丁酸代谢途径在高山被孢霉脂质合成中的作用

M. alpina is industrial oleaginous fungi with a variety of n-3 and n-6 series of polyunsaturated fatty acids (PUFAs). γ-aminobutyric acid (GABA) can not only provide nitrogen and carbon for the growth of fungi but provide NADPH for lipid synthesis. By constructing recombinant strain (MA- iSSADH), this study analyzed the composition of fatty acid, the content of NADPH and the level of transcription of relevant genes of generating NADPH to iThe role of γ -aminobutyric acid shunt pathway in lipogenesis in Mortierella alpinanvestigate the role of GABA pathway in M. alpine during lipid synthesis. Compared with M. alpina, the transcriptional level of SSADH decreased significantly and the content of total fatty acid decreased by 20% while the relative content of C18: 1 increased by 70% in MA-iSSADH. It indicates that the GABA pathway plays an important role in the lipid synthesis of M. alpina. Although there was no obvious change in content of NADPH, the transcriptional level of related genes of generating NADPH such as malic acid (ME), glucose-6-phosphate dehydrogenase (G6PD), 6-phosphogluconate dehydrogenase (PGD), Isocitrate hydrogenase (IDH) and methylenetetrahydrofolate dehydrogenase (MTHFD) has changed significantly. This shows that GABA pathway regulates the source of NADPH required for the synthesis of lipid synthesis, and thus plays an important role in lipogenesis in M. alpina.