Structure characterization of an exopolysaccharide from a Shiraia-associated bacterium and its strong eliciting activity on the fungal hypocrellin production

Lu Lu Zhou, Wen Hao Shen, Yan Jun Ma, Xin Ping Li, Jian Yong Wu, Jian Wen Wang

Research output: Journal article publicationJournal articleAcademic researchpeer-review

7 Citations (Scopus)

Abstract

Hypocrellins are fungal perylenequinones (PQs) from Shiraia fruiting bodies and potential photosensitizers for cancer photodynamic therapy. Shiraia fruiting bodies harbor diverse bacterial communities dominated by Pseudomonas. The present study was to characterize the exopolysaccharide (EPS) of P. fulva SB1 which acted as an elicitor to stimulate the PQ accumulation of the host Shiraia. A bacterial EPS named EPS-1 was purified from the culture broth of P. fulva SB1, which consisted of mannose (Man) and glucose (Glc) with an average molecular weight of 9.213 × 104 Da. EPS-1 had (1 → 2)-linked α-mannopyranose (Manp) backbone and side chains of α-D-Manp-(1→ and α-D-Manp-(1 → 6)-β-D-Glcp-(1 → 6)-α-D-Manp(1 → group attached to the O-6 positions of (1 → 2)-α-D-Manp. EPS-1 at 30 mg/L stimulated both intracellular and extracellular hypocrellin A (HA) by about 3-fold of the control group. The EPS-1 treatment up-regulated the expression of key genes for HA biosynthesis. The elicitation of HA biosynthesis by EPS-1 was strongly dependent on the induced reactive oxygen species (ROS) generation. The results may provide new insights on the role of bacterial EPS in bacterium-fungus interactions and effective elicitation strategy for hypocrellin production in mycelial cultures.

Original languageEnglish
Pages (from-to)423-433
Number of pages11
JournalInternational Journal of Biological Macromolecules
Volume226
DOIs
Publication statusPublished - 31 Jan 2023

Keywords

  • Elicitation
  • Exopolysaccharide
  • Hypocrellin
  • Pseudomonas fulva SB1
  • Shiraia
  • Structure elucidation

ASJC Scopus subject areas

  • Structural Biology
  • Biochemistry
  • Molecular Biology

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