Fish-microbe systems in the hostile but highly biodiverse Amazonian blackwaters

Sylvain, F.-E.; Leroux, N.; Normandeau, E.; Custodio, J.; Mercier, P.-L.; Bouslama, S.; Holland, A.; Barroso, D.; Luis Val, A.; Derome, N. J. A.

doi:10.1101/2022.10.22.513327

bioRxiv · 10.1101/2022.10.22.513327

Fish-microbe systems in the hostile but highly biodiverse Amazonian blackwaters

Sylvain, F.-E.·Leroux, N.·Normandeau, E.·Custodio, J.·Mercier, P.-L.·Bouslama, S.·Holland, A.·Barroso, D.·Luis Val, A.·Derome, N. J. A.

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Abstract

Amazonian blackwaters are extremely biodiverse systems containing some of the most naturally acidic, dissolved organic carbon-rich and ion-poor waters on Earth. Physiological adaptations of fish facing these ionoregulatory challenges are unresolved but could involve microbially-mediated processes. Here, we characterize the physiological response of 964 fish-microbe systems from four blackwater Teleost species along a natural hydrochemical gradient, using dual RNA-Seq and 16S rRNA of gill samples. We find that responses to blackwaters are host-species-specific, but occasionally include the overexpression of Toll-receptors and integrins associated to interkingdom communication. Blackwater gill microbiomes are characterized by a transcriptionally-active betaproteobacterial cluster potentially interfering with epithelial permeability. We explore further blackwater fish-microbe interactions by analyzing transcriptomes of 320 axenic zebrafish larvae exposed to sterile, non-sterile and inverted (non-native bacterioplankton) blackwater. We find that axenic zebrafish do not survive well when exposed to sterile/inverted blackwater, suggesting an essential role of endogenous symbionts in blackwater fish physiology.

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Sylvain, F.-E., Leroux, N., Normandeau, E., Custodio, J., Mercier, P.-L., Bouslama, S., Holland, A., Barroso, D., Luis Val, A., Derome, N. J. A.. 2022-10-24. Fish-microbe systems in the hostile but highly biodiverse Amazonian blackwaters. https://doi.org/10.1101/2022.10.22.513327

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