Abstract
Background: Species under the genus Monascus are considered as economically important and have been widely used in the production of yellow and red food colorants. In particular, three Monascus species, namely, M. pilosus , M. purpureus , and M. ruber , are used for food fermentation in the cuisine of East Asian countries such as China, Japan, and Korea. These species have also been utilized in the production of various kinds of natural pigments. Results: We examined the diversity of pigment-related biosynthetic pathways in three Monascus species ( M. pilosus , M. purpureus , and M. ruber ) at the metabolome and genome levels. Illumina MiSeq 300 bp paired-end sequencing generated 17 million high-quality short reads in each species, corresponding to 200 times the genome size. We measured the pigments and their related metabolites using potato dextrose liquid (PDL) media. The colors in the PDL media corresponding to the pigments and their related metabolites produced by the three species are very different from each other. The gene clusters for secondary metabolite biosynthesis of the three Monascus species also diverged, confirming that M. pilosus and M. purpureus are chemotaxonomically different. M. ruber has similar biosynthetic gene clusters for citrinin, monacolin K, and Monascus azaphilone pigments with M. pilosus and M. purpureus. The comparison of secondary metabolites produced also revealed divergence in the three species. Conclusions: Our findings are important for improving the utilization of Monascus species in the food industry and industrial field. However, in view of food safety, we need to determine if the toxins produced by some Monascus strains exist in the genome or in the metabolome.
antiSMASH: rapid identification, annotation and analysis of secondary metabolite biosynthesis gene clusters in bacterial and fungal genome sequences
