# Chemical investigation of the halotolerant yeast Hortaea werneckii

Elise Gerometta, Rafia Ahmed Tuli, Chloe Gros, Bastien Cochereau, Emmanuel Gentil, Laurence Meslet-Cladiere, Deniz Tasdemir, Nina Gunde-Cimerman, Monika Kos, Catherine Roullier

► To cite this version:

Elise Gerometta, Rafia Ahmed Tuli, Chloe Gros, Bastien Cochereau, Emmanuel Gentil, et al.. Chemical investigation of the halotolerant yeast Hortaea werneckii. XVII MaNaPro - XIII ECMNP, Sep 2023, Grenade (Espagne), Spain. hal-04830020

HAL Id: hal-04830020

https://hal.science/hal-04830020v1

Submitted on 10 Dec 2024

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Distributed under a Creative Commons Attribution 4.0 International License
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ELISE GEROMETTA*¹, RAFIA AHMED TULI¹, CHLOE GROS¹, BASTIEN COCHEREAU¹, EMMANUEL GENTIL¹, LAURENCE MESLET-CLADIERE², DENIZ TASDEMIR³, NINA GUNDE-CIMERMAN⁴, MONIKA KOS⁴, CATHERINE ROULLIER¹

¹ Nantes Université, Institut des Substances et Organismes de la Mer, ISOMer, UR 2160, F-44000 Nantes, France.
² Univ Brest, INRAE, Laboratoire Universitaire de Biodiversité et Écologie Microbienne, F-29280 Plouzané, France.
³ GEOMAR Centre for Marine Biotechnology, Research Unit Marine Natural Products Chemistry, 24106 Kiel, Germany.
⁴ University of Ljubljana, Biotechnical Faculty, Department of Biology, 1000 Ljubljana, Slovenia.

Corresponding Author: elise.gerometta@univ-nantes.fr

## Background

*Hortaea werneckii* (Ascomycota, Dothideomycetes) is a filamentous halotolerant black yeast, distributed primarily in hypersaline, marine and in terrestrial environments, from Atacama Desert rocks to deep sea water¹,². So far, this species was mainly studied as a biological model to understand the halotolerance mechanisms in eukaryotic cells³,⁴. While some biosynthetic gene clusters seem to be present in this yeast⁵,⁶, very few chemical investigations have been carried out (only 3 metabolites isolated), making *H. werneckii* an interesting candidate for the discovery of new metabolites and bioactive molecules. On the other hand, Gostinčar *et al.* (2022) (University of Ljubljana) have conducted a large genomic study on this species, by sequencing 64 strains isolated from multiple environments around the world¹. This work led to a collaboration between our lab teams, in order to investigate the chemical diversity of the species and identify a possible relationship between the metabolomes and the genomes.

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* Investigate the chemical diversity of the 64 sequenced strains through a metabolomic study.
* Highlight some interesting chemical entities.
* Identify a possible relationship between the metabolome and the genome of the strains.
* Isolate and identify new and bioactive compounds from the yeast.

## Metabolomic study

### Samples preparation

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### Data acquisition and treatment

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## Statistical analysis and molecular networking

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* The PCA highlighted two groups of samples: non-salt media samples (NS) and salt media samples (S).
* The 3D Scores plot again showed that most of the variability of the samples was due to the presence of salt in the media. Information addition about the ploidy level (different shapes) did not display any significant clustering according to this data. Similar results were observed with the habitat (marine/terrestrial) or continent where the strains were collected. Further investigations on other principal components could provide other meaningful information about the influence of the ploidy level or the habitat of the strains.

<figure><img src="image_9.png" /><figcaption>Hierarchical Clustering Analysis of
the 25 most important features by Heatmap</figcaption></figure>

* **Hierarchical clustering** is presented for the 25 most important features for a better visualisation. **8 mid-polar** to **apolar** (RT 9.9-29.7 min) and **putatively identified** features are highly produced in **S media** and absent in **NS media**.

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* **A molecular network** of 285 nodes was obtained. The 8 discriminant features (S media) are non-clustered. Several spectral families were highlighted, but few spectral matches have been obtained on GNPS databases, indicating potential new structures.

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## References

1. C. Gostinčar et al., *GigaScience*, 2022, 11, 1-16; 2. N. Gunde-Cimerman and A. Plemenitaš. *Rev. Environ. Sci. Biotechnol*, 2006, 5, 323-331; 3. A. Marchetta et al., *Life*, 2018, 8, 31; 4. N. Gunde-Cimerman et al., *FEMS Microbiol. Rev.*, 2018, 42, 353-375; 5. I.V. Grigoriev et al., *Nucleic Acids Res.*, 2014, 42, D699-D704; 6. K. Blin et al., *Nucleic Acids Res.*, 2021, 49, W29-W35.

## Compounds isolation

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## Conclusion & Perspectives

According to the **metabolomic** study,

* **No relationship** between the **genomes** and the **metabolomes** of the strains could be observed.

* The **salt content** in media is the main factor inducing a modulation of the strains metabolites production.

* The metabolites specifically produced in salt media are **mid-polar** to **apolar**, and should be isolated and identified.

* **Hortein** has been identified as an **ubiquitous** metabolite, and could be considered as a chemical marker of *Hortaea werneckii*.

* Several **spectral families**, including **hortein analogues**, have been identified on the molecular network.

In order to complete this work, the following perspectives are considered:

* **Dereplication** of features using **ChromAnnot**

* Large-scale culture on **MEA 17% NaCl** media

* **Isolation** and **identification** of the discriminant metabolites

* Obtention of **hortein analogues** in order to evaluate their **biological activities** and highlight a potential **structure-activity relationship**

From the strain grown on PDA media,

* **Four metabolites** were isolated.

* One of them was identified as **hortein** based on MS and UV spectra.

* Another was putatively identified as **isobalticol B-4,9-acetonide**.

Thus, the following steps will be soon conducted:

* **Identification** of the isolated metabolites (HRMS, NMR)

* **Bioactivity assays** on the isolated metabolites

## Financial support

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ANR-21-CE44-0003 HALO-CAT