Mining new meroterpenoids from the marine red alga-derived endophytic Penicillium chermesinum EN-480 by comparative transcriptome analysis

As the development of genetic and bioinformatic, the strategy of bottom-up, combined with genome and transcriptome techniques, was considered as an efficient and practical method to break through the limitation of traditional discovery of natural products. Generally, comparative transcriptome analysis could be useful to guide the optimization of fungal cultivation conditions in which the transcriptional level of interesting compounds is higher. The transcriptome analysis of the algal endophytic fungus Penicillium chermesinum EN-480 indicated that fermentation of this fungus in modified rice solid medium could produce some metabolites different from those cultivated in other media. Four new meroterpenoids (compounds 1-4, namely, chermesins E-H) were characterized and their structures were determined by HRESIMS and NMR spectra. The absolute configurations were confirmed by NOESY experiments, X-ray diffraction analysis, and comparison of ECD cotton effects. Antimicrobial activities against human- and aqua-bacteria as well as against plant-pathogenic fungi were assayed. The plausible biosynthesis pathway of these compounds was discussed.

Automated summary

The transcriptome analysis of the algal endophytic fungus Penicillium chermesinum EN-480 revealed that fermentation in modified rice solid medium could lead to the production of new meroterpenoids with different structures compared to other media. These compounds showed antimicrobial activity against human- and aqua-bacteria as well as plant-pathogenic fungi. The study also discussed the possible biosynthesis pathway of these compounds.