AUTHOR=Ma Yan Jun , Zheng Li Ping , Wang Jian Wen 

TITLE=Bacteria Associated With Shiraia Fruiting Bodies Influence Fungal Production of Hypocrellin A

JOURNAL=Frontiers in Microbiology

VOLUME=10

YEAR=2019

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2019.02023

DOI=10.3389/fmicb.2019.02023

ISSN=1664-302X

ABSTRACT=<p>Hypocrellin A (HA) is a natural red perylenequinone pigment from <italic>Shiraia</italic> 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 <italic>Shiraia</italic> 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 <italic>Bacillus</italic> and <italic>Pseudomonas</italic>. Some <italic>Pseudomonas</italic> isolates such as <italic>P. fulva</italic>, <italic>P. putida</italic>, and <italic>P. parafulva</italic> could stimulate fungal HA accumulation by <italic>Shiraia</italic> sp. S9. The bacterial treatment of <italic>P. fulva</italic> SB1 up-regulated the expression of polyketide synthase (<italic>PKS</italic>) for HA biosynthesis and transporter genes including ATP-binding cassette (<italic>ABC</italic>) and major facilitator superfamily transporter (<italic>MFS</italic>) for HA exudation. After the addition of live <italic>P. fulva</italic> SB1, the mycelium cultures of <italic>Shiraia</italic> sp. S9 presented a higher HA production (225.34 mg/L), about 3.25-fold over the mono-culture. On the other hand, <italic>B. cereus</italic> was capable of alleviating fungal self-toxicity from HA <italic>via</italic> 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 <italic>Shiraia</italic> 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 <italic>Shiraia</italic>.</p>