Combination Strategy of Genetic Dereplication and Manipulation of Epigenetic Regulators Reveals a Novel Compound from Plant Endophytic Fungus

The strategies of genetic dereplication and manipulation of epigenetic regulators to activate the cryptic gene clusters are effective to discover natural products with novel structure in filamentous fungi. In this study, a combination of genetic dereplication (deletion of pesthetic acid biosynthetic gene, PfptaA) and manipulation of epigenetic regulators (deletion of histone methyltransferase gene PfcclA and histone deacetylase gene PfhdaA) was developed in plant endophytic fungus Pestalotiopsis fici. The deletion of PfptaA with PfcclA and/or PfhdaA led to isolation of 1 novel compound, pestaloficiol X (1), as well as another 11 known compounds with obvious yield changes. The proposed biosynthesis pathway of pestaloficiol X was speculated using comparative analysis of homologous biosynthetic gene clusters. Moreover, phenotypic effects on the conidial development and response to oxidative stressors in the mutants were explored. Our results revealed that the new strain with deletion of PfcclA or PfhdaA in Delta PfptaA background host can neutralise the hyperformation of conidia in the PfptaA mutant, and that the Delta PfptaA Delta PfhdaA mutant was generally not sensitive to oxidative stressors as much as the Delta PfptaA Delta cclA mutant in comparison with the single mutant Delta PfptaA or the parental strains. This combinatorial approach can be applied to discover new natural products in filamentous fungi.

Automated summary

The strategies of genetic dereplication and manipulation of epigenetic regulators have been found effective in discovering natural products with novel structures in filamentous fungi. In this study, a combination of genetic dereplication and manipulation of epigenetic regulators was used to discover a novel compound, pestaloficiol X, and other known compounds in the plant endophytic fungus Pestalotiopsis fici. The study also proposed a possible biosynthesis pathway for pestaloficiol X based on comparative analysis of homologous biosynthetic gene clusters. Additionally, the study explored the effects of the mutants on conidial development and response to oxidative stressors.