*Article Trichoderma reesei* **Contains a Biosynthetic Gene Cluster That Encodes the Antifungal Agent Ilicicolin H**

**Mary L. Shenouda 1,2, Maria Ambilika <sup>1</sup> and Russell J. Cox 1,\***

1


**\*** Correspondence: russell.cox@oci.uni-hannover.de

**Abstract:** The *trili* biosynthetic gene cluster (BGC) from the well-studied organism *Trichoderma reesei* was studied by heterologous expression in the fungal host *Aspergillus oryzae*. Coexpression of *triliA* and *triliB* produces two new acyl tetramic acids. Addition of the ring-expanding cytochrome P450 encoded by *triliC* then yields a known pyridone intermediate to ilicicolin H and a new chaintruncated shunt metabolite. Finally, addition of the intramolecular Diels-Alderase encoded by *triliD* affords a mixture of 8-epi ilicicolin H and ilicicolin H itself, showing that the *T. reesei trili* BGC encodes biosynthesis of this potent antifungal agent. Unexpected *A. oryzae* shunt pathways are responsible for the production of the new compounds, emphasising the role of fungal hosts in catalysing diversification reactions.

**Keywords:** heterologous expression; PKS-NRPS; ilicicolin H; shunt metabolite; *Trichoderma reesei*

**Citation:** Shenouda, M.L.; Ambilika, M.; Cox, R.J. *Trichoderma reesei* Contains a Biosynthetic Gene Cluster That Encodes the Antifungal Agent Ilicicolin H. *J. Fungi* **2021**, *7*, 1034. https://doi.org/10.3390/jof7121034

Academic Editors: Tao Feng and Frank Surup

Received: 8 November 2021 Accepted: 29 November 2021 Published: 1 December 2021

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