Project description:M. purpureus YY-1 is widely used in food colorant production in China. In our previous study, the whole-genome information of YY-1 was clearly illustrated, which provided useful hints for evolution esearch and industrial applications. However, the presence of citrinin, which has nephrotoxic, hepatotoxic, and carcinogenic activities, attracts people′s attention to the safety of Monascus products. In order to reduce the harm of citrinin in Monascus related products, in this study, a random mutant of M. purpureus YY-1, with scarce citrinin production (designated as winter) was obtained. To analyze the biosynthesis and regulation mechanism of pigment and citrinin, transcriptomic analysis of M. purpureus YY-1 and winter was performed. Comparative transcriptomic analysis reveals pksCT, the essential gene for citrinin synthesis, showed low expression level in M. purpureus YY-1 and winter, which suggested there might be isoenzymes in M. purpureus YY-1 that were responsible for the citrinin synthesis during evolution. In addition, the expression change of transcription factors may also influence the regulatory network of citrinin synthesis pathway of in M. purpureus. Moreover, the yields of pigments produced by the winter mutant were significantly increased. Repressing central carbon metabolism and improving the acetyl-CoA pool can contribute to the high yield of pigments, and enhanced NADPH regeneration also lead the metabolic flux to pigments in M. purpureus. Investigations on biosynthesis and regulation of citrinin and pigment production in M purpureus will enhance our knowledge of the mechanisms in fungal secondary metabolite biosynthesis.
