Bacteria Associated With Fruiting Bodies Influence Fungal Production of Hypocrellin A.

Hypocrellin A (HA) is a natural red perylenequinone pigment from fruiting body, which was used clinically on various skin diseases and developed as a photodynamic therapy agent against cancers. The fruiting bodies may harbor a diverse but poorly understood microbial community. In this study, we characterized the bacterial community of fruiting body using a combination of culture-based method and Illumina high-throughput sequencing, and tested the involvement of some companion bacteria in fungal HA production using the fungal-bacterial confrontation assay. Our results revealed that the bacterial community in the fruiting body was dominated by and . Some isolates such as , , and could stimulate fungal HA accumulation by sp. S9. The bacterial treatment of SB1 up-regulated the expression of polyketide synthase () for HA biosynthesis and transporter genes including ATP-binding cassette () and major facilitator superfamily transporter () for HA exudation. After the addition of live SB1, the mycelium cultures of sp. S9 presented a higher HA production (225.34 mg/L), about 3.25-fold over the mono-culture. On the other hand, was capable of alleviating fungal self-toxicity from HA down-regulation of HA biosynthetic genes or possible biodegradation on HA. To our knowledge, this is the first report on the diversified species of bacteria associated with fruiting bodies and the regulation roles of the companion bacteria on fungal HA biosynthesis. Furthermore, the bacterial co-culture provided a good strategy for the enhanced HA production by .