基于红曲菌基因组揭示光影响红曲色素发酵的分子机理

Monascus pigments (MPs) are one of main metabolites produced by M. spp., which are distinctive edible microbes in China. MPs have been used as food colorant for more than one thousand years in China. Recently in China MPs have been become food colorant which were increased the most quickly due to their safety, stability, etc. Besides food colorant, MPs possess a range of biological activities, such as antioxidant activities, anti-tumor activities, and so on. MPs can also be applied in solar cells and biological dyeing, indicating a widespread application field. Now how to enhance MPs productivity during their fermentation, especially in liquid-state fermentation is an urgent issue. As we know, screening high-yield-MPs strains and optimizing MPs fermentation conditions are commonly used methods, but it is very difficult to get a good result. .Recently, researches have shown that red lights can remarkly improve MPs yield. However, relative technologies have not been developed and applied until now, since influence mechanism of lights on MPs production is unclear. In current proposal, on the basis of the genome of M. ruber M-7, MPs gene clusters, and red light receptor genes, which were obtained from the early stage researches in our research group, the following studies will be carried out. The research contents mainly include analyzing the effects of lights with different colors and intensities on MPs production, discovering new light receptors and their genes, investigating a network and the relative genes of MPs production regulated by lights, constructing engineering strains with safe and high-efficient MPs production through gene knock-out technology, and discussing molecular mechanism of light effects on MPs fermentation..The results will provide theory and technological foundation for how to increase the MPs amount during fermentation.

红曲色素（Monascus pigments, MPs）是我国特色食用微生物红曲菌（M. spp.）的主要代谢产物之一，作为食品着色剂在我国有上千年应用历史。MPs具有天然、安全等特点，是目前我国增长最快的食品着色剂。MPs还具有抗氧化和抗肿瘤等活性，也可用于太阳能电池与生物印染。应用范围非常广阔。如何提高MPs产率，特别是液体发酵产率是迫切需要解决的问题，但目前的方法效果均不很理想。.最近研究表明，红光能显著提高MPs液态发酵产率，但机理不明，阻碍了相关技术的开发与应用。本研究将以前期获得的红色红曲菌（M. ruber）M-7的基因组、MPs基因簇和红光受体基因等为基础，系统分析不同颜色与强度的光对MPs产生的影响，发掘红光受体以外的新受体与基因，分析光调控MPs产生网络与相关基因，探讨光影响MPs发酵分子机理，构建高效安全的MPs工程菌，为光照技术提高MPs产率提供理论与技术支撑。

红曲菌（Monascus spp.），又称红曲霉，是我国重要的食用微生物，其米饭固体发酵产品——红曲，作为食品着色剂、防腐剂、发酵剂与中药配伍等在我国及东南亚地区已有近2000年应用历史。红曲也是我国传统、特色出口产品。其中，红曲色素（Monascus pigments，MPs）作为着色剂，一直广泛用于我国的食品工业。由于MPs具有天然、安全、生产不受原料与季节限制等优势，所以销量逐年增加，是近年来我国增长速度最快的食品着色剂之一。目前，MPs主要通过液态发酵法生产，但存在MPs产率偏低等急需解决的问题。最近的研究表明，光照对MPs 的产生影响巨大，但光影响MPs 产生的机理不明，阻碍了相关技术的研发与应用。本项目以红、黄、绿、蓝和紫光的LED灯为光源，系统研究了不同光照强度对红曲菌生物量、MPs与桔霉素（Citrinin，CIT，某些红曲菌产生的肾脏真菌毒素）的影响；采用比较基因组学方法，通过对红曲菌基因组的系统分析，在红曲菌中首次发现了绿光受体基因，但不存在任何蓝光受体基因；在此基础上，构建了红曲菌1个红光受体基因和2个绿光受体基因的敲除、回补和过表达突变菌株（工程菌株）；通过分析蓝光对红曲菌生长与MPs和CIT影响，发现蓝光对红曲菌生长和次生代谢的影响可能不是通过蓝光受体实现的，并推导出蓝光对红曲菌影响的分子途径；构建了相应工程菌株，分析了它们在不同光照条件下MPs和CIT的产生进程；还阐明（重构）了MPs（CIT）的生物合成途径，顺利完成各项研究内容，达到预期的研究目标。本项目的研究结果为通过光照提高红曲菌MPs的产率，降低其CIT的产生奠定了良好的基础。