Discovery of polyketide natural products from corals derived fungi Parengyodontium album SCSIO SX7W11 and their biosynthetic pathway analysis

Abstract:

Natural products from marine fungi have been attracting attention for their unique structures and biological activities. Genome mining has become an emerging strategy to explore their metabolites. [Objective] In this study, we investigated Parengyodontium album SCSIO SX7W11, a marine fungus derived from South China Sea corals for the potential of producing polyketides. [Methods] We sequenced the whole genome of strain SX7W11 using Illumina Miseq. The polyketide biosynthetic gene clusters were then predicted and the functions of open reading frames (ORFs) were annotated. Normal phase chromatography, reversed-phase chromatography, Sephadex LH-20 chromatography, and High Performance Liquid Chromatography (HPLC) were conducted for the isolation and purification of natural products. The purified compounds were characterized by high resolution mass spectrometry (HR-ESI-MS), ¹H NMR, ¹³C NMR and X-ray data and the biosynthetic pathways were deduced. [Results] The whole genome scanning and sequencing results showed that the genome length of SX7W11 is 34.0 Mb, containing 24 biosynthetic gene clusters. Three polyketides were identified as emodin (1), alternaphenol B (2), and sydowinin A (3). The crystal data of sydowinin A was obtained. The biosynthetic gene cluster of sydowinin A was localized from SX7W11 genome by bioinformatics analysis. The biosynthetic pathway was then proposed. [Conclusion] Through genome mining and medium optimization, P. album SCSIO SX7W11, a coral derived fungus, has shown the potential to produce sydowinin type polyketides. This work laid a foundation for the biosynthesis study of sydowinin.