# Extent of Microsporidia diversity and host range in lake ecosystems

Marina Chauvet, Aurore Dubuffet, Anne Moné, Didier Debroas, Cécile Lepère

► To cite this version:

Marina Chauvet, Aurore Dubuffet, Anne Moné, Didier Debroas, Cécile Lepère. Extent of Microsporidia diversity and host range in lake ecosystems. 24èmes Journees de l'Ecole Doctorale Sciences de la Vie, Santé, Agronomie, Environnement, Jun 2021, Clermont-Ferrand, France. hal-04795845

HAL Id: hal-04795845

https://hal.science/hal-04795845v1

Submitted on 21 Nov 2024

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<figure><img src="image_1.png" /></figure>

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# 1 Introduction

Microsporidia are obligate intracellular parasites with a wide host spectrum, known primarily as parasites of vertebrates and invertebrates. However, their global diversity as well as their impact on small-sized aquatic hosts (e.g. protists, microzooplankton) remain largely underestimated. Thanks to the use of specific primers in a metabarcoding approach and microscopic observations (TSA-FISH) we studied the diversity of Microsporidia and identified the extent of their host spectrum in <150 µm size fraction in lake ecosystems.

# 2 Microsporidia diversity

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# Extent of Microsporidia diversity and host range in lake ecosystems

# 3 Identification of potential hosts

Co-occurence network (SPIEC-EASI(1)) between microsporidian OTUs and eukaryotic OTUs

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* High diversity: ~ 1 500 OTUs

* 40% of the OTUs not assigned to a genus

* Temporal variations

Metabarcoding:
Microsporidia specific primers
& universal eukaryotic primers

Illumina MiSeq sequencing

<figure><img src="image_4.png" /><figcaption>Lake Aydat (France)</figcaption></figure>

Universal Microsporidia
probe - TSA-FISH

# 4 Host-parasite associations

Scale bars: 10 µm

<figure><img src="image_5.png" /><figcaption>Rotifer</figcaption></figure>

<figure><img src="image_6.png" /><figcaption>Ciliates</figcaption></figure>

<figure><img src="image_7.png" /><figcaption>Microsporidia
attached to a
diatom cell</figcaption></figure>

<figure><img src="image_8.png" /><figcaption>Microsporidia
attached to a colonial
Chlorophyceae</figcaption></figure>

# 5 Conclusion

Our results show a great Microsporidia diversity, with an important part of this diversity being unknown. Temporal variations in this diversity have been observed, they might follow temporal variations of their hosts (e.g. microeukaryotes and metazooplankton). Co-occurrence networks along with TSA-FISH showed Microsporidia in association with protists and microzooplankton (e.g. Ciliates, Rotifers) as well as phytoplankton (e.g. Diatoms, Chlorophyceae). Their host spectrum could be therefore even more important than previously described, and their role in the functioning of lake ecosystems is undoubtedly largely unknown.
Infection tests in microcosms will be carried out to confirm these potential associations. This will also allow us to study host-parasite interactions through morphological observations and single-cell sequencing.

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