Liu Jiao, Zhou Youxiang, Yi Tao, Zhao Mingming, Xie Nana, Lei Ming, Liu Qingpei, Shao Yanchun, Chen Fusheng
College of Food Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China.
Institute of Quality Standard and Testing Technology for Agro-Products, Hubei Academy of Agricultural Sciences, Wuhan, 430070, China.
Appl Microbiol Biotechnol. 2016 Aug;100(16):7037-49. doi: 10.1007/s00253-016-7397-8. Epub 2016 Mar 5.
Monascus pigments (Mps) are a group of azaphilonic secondary metabolites produced by Monascus spp. via a polyketide pathway. A mutant deleted an about 30 kb region of Mps gene cluster from Monascus ruber M7 was isolated previously, which produces a high amount of a light yellow pigment. The current study revealed that the mutant named ΔMpigJ-R lost proximate eight genes of the Mps gene cluster in M. ruber M7 through genetic analysis at DNA and RNA levels. The produced light yellow material was identified as a benzaldehyde derivative named as 6-(4-hydroxy-2-oxopentyl)-3-methyl-2, 4-dioxocyclohexane carb-aldehyde (M7PKS-1) by FT-IR, NMR, and MS. The sodium acetate-1-(13)C feeding experiment indicated that M7PKS-1 was a product produced from polyketide pathway. Finally, the feeding of M7PKS-1 helped to induce and regain Mps production of the mutants (ΔMpigA and ΔMpigE) which were previously unable to biosynthesize Mps and proved that M7PKS-1 was an initial intermediate of Mps. The results in this study provide a line of action to unveil Monascus pigments biosynthesis pathway.
红曲色素（Mps）是红曲霉菌通过聚酮途径产生的一组含氮杂环类次级代谢产物。先前从红曲M7中分离出一个缺失约30 kb红曲色素基因簇区域的突变体，该突变体产生大量浅黄色色素。当前研究表明，通过DNA和RNA水平的遗传分析，名为ΔMpigJ-R的突变体在红曲M7中缺失了红曲色素基因簇的近八个基因。通过傅里叶变换红外光谱（FT-IR）、核磁共振（NMR）和质谱（MS）将所产生的浅黄色物质鉴定为一种苯甲醛衍生物，命名为6-(4-羟基-2-氧代戊基)-3-甲基-2,4-二氧代环己烷甲醛（M7PKS-1）。乙酸钠-1-(13)C饲喂实验表明M7PKS-1是聚酮途径产生的产物。最后，饲喂M7PKS-1有助于诱导并恢复先前无法生物合成红曲色素的突变体（ΔMpigA和ΔMpigE）的红曲色素产生，并证明M7PKS-1是红曲色素的初始中间体。本研究结果为揭示红曲色素生物合成途径提供了一条行动路线。
