Molecular Mechanism of Gene Overexpression in Enhancing Monacolin K Production in .

species are capable of producing various active metabolites, including monacolin K (MK) and pigments. Studies have shown that the overexpression of the gene from the MK synthesis gene cluster in species can significantly increase MK production; however, the molecular mechanism has not yet been fully elucidated. Therefore, this study focused on the gene of to construct overexpression strains of the gene, resulting in high-yield MK production. Sixteen positive transformants were obtained, seven of which produced 9.63% to 41.39% more MK than the original strain, with no citrinin detected in any of the transformants. The qRT-PCR results revealed that the expression levels of in the transformed strains TI-13, TI-24, and TI-25 increased by more than 50% compared to the original strain at various fermentation times, with the highest increase being 10.9-fold. Furthermore, multi-omics techniques were used to analyze the molecular mechanisms underlying enhanced MK production in transformed strains. The results indicated that overexpression may enhance MK synthesis in by regulating the expression of key genes (such as , , , and ) and the synthesis levels of key metabolites (such as delta-tocopherol and alpha-linolenic acid) in pathways linked to the biosynthesis of cofactors, the biosynthesis of unsaturated fatty acids, tyrosine metabolism, ubiquinone and other terpenoid-quinone biosynthesis, alpha-linolenic acid metabolism, and glycerophospholipid metabolism. These findings provide a theoretical basis for further study of the metabolic regulation of MK in species and for effectively enhancing their MK production.