A Negative Regulator of Carotenogenesis in

As an ideal carotenoid producer, has gained much attention due to its large biomass and high production of β-carotene and lycopene. However, carotenogenesis regulation in still needs to be clarified, as few investigations have been conducted at the molecular level in In this study, a gene homologous to carotenogenesis regulatory gene () was cloned from the mating type (-) of , and the deduced CrgA protein was analyzed for its primary structure and domains. To clarify the -mediated regulation in , we used the strategies of gene knockout and complementation to investigate the effect of expression on the phenotype of In contrast to the wild-type strain, the null mutant (Δ) was defective in sporulation but accumulated much more β-carotene (31.2% improvement at the end) accompanied by enhanced transcription of three structural genes (, , and ) for carotenoids throughout the culture time. When the wild-type copy of was complemented into the null mutant, sporulation, transcription of structural genes, and carotenoid production were restored to those of the wild-type strain. A gas chromatography-mass spectrometry (GC-MS)-based metabolomic approach and multivariate statistical analyses were performed to investigate the intracellular metabolite profiles. The reduced levels of tricarboxylic acid (TCA) cycle components and some amino acids and enhanced levels of glycolysis intermediates and fatty acids indicate that more metabolic flux was driven into the mevalonate (MVA) pathway; thus, the increase of precursors and fat content contributes to the accumulation of carotenoids. The zygomycete is an important strain for the production of carotenoids on a large scale. However, the regulation mechanism of carotenoid biosynthesis is still not well understood in this filamentous fungus. In the present study, we sought to investigate how influences the expression of structural genes for carotenoids, carotenoid biosynthesis, and other anabolic phenotypes. This will lead to a better understanding of the global regulation mechanism of carotenoid biosynthesis and facilitate engineering this strain in the future for enhanced production of carotenoids.