Biosynthetic machineries of anthraquinones and bisanthraquinones in Talaromyces islandicus.

Talaromyces islandicus is a unique fungus that produces more than 20 numbers of anthraquinones (AQs) and their dimeric natural products, bisanthraquinones (BQs). These compounds share a 9,10-anthracenedione core derived from emodin. The biosynthetic pathway of emodin has been firmly established, while that of other AQs and BQs is still unclear. In this study, we identified the biosynthetic gene clusters for chrysophanol and skyrin. The function of key modification enzymes was examined by performing biotransformation experiments and in vitro enzymatic reactions with emodin and its derivatives, allowing us to propose a mechanism for the modification reactions. The present study provides insight into the biosynthesis of AQs and BQs in T. islandicus.