Fatty acid synthase in high and low lipid-producing strains of Mucor circinelloides: identification, phylogenetic analysis, and expression profiling during growth and lipid accumulation.

Fatty acid synthase (FAS) is one of the most important enzymes in lipid biosynthesis, which can catalyze the reaction of acetyl-CoA and malonyl-CoA to produce fatty acids. However, the structure, function, and molecular mechanism of FAS regulating lipid synthesis in the fungus Mucor circinelloides are unclear. In the present study, two encoding fas genes in the high lipid-producing strain WJ11 and low lipid-producing strain CBS277.49 from M. circinelloides based on their genome database were identified and annotated respectively. Bioinformatic analysis confirmed the presence of typical conserved domains in FAS proteins. Phylogenetic analysis revealed the evolutionary relationship of these FAS proteins, and the FAS proteins from WJ11 have similar properties as their counterparts in CBS277.49. Furthermore, transcriptional profiling displayed marked differences in the expression of these fas genes, and fas1 was analyzed to predict the possible functions in lipid metabolism in the high lipid-producing strain WJ11. This is the first report on the structures and functions of FAS proteins in M. circinelloides. This research has suggested the association of fas genes with lipid metabolism at the transcriptional level and contributed to the selection of candidates related to lipid metabolism for further study.