Are anaerobic fungi crucial hidden players of microbiomes in anoxic environment?

Abstract

Anaerobic fungi are known to migrate and establish a 3D network of biofilms (microbiomes) and live invisible in the rumen and terrestrial subsurface, deep-sea - marine, and anoxic environment. They deserve our attention to understand anoxic fungal ecology and functions and develop new products and solutions. Such fungi activate unique genes to produce various polysaccharidases deemed essential for degrading plants’ lignocellulosic materials. Nutrient release, recycling, and physical support by anaerobic fungi are crucial for microbiome formation. Multiple reports point to the ability of strictly anaerobic and facultative fungi to adapt and live in anoxic subsurface. Deep-sea sediments and natural anoxic methane-emitting salty waters of sulfidic springs offer suitable habitats for developing prokaryotic-fungal microbiomes. Researchers found a billion-year-old fossil of the fungus-prokaryotic sulfate-reducing consortium buried in deep-sea biospheres. Fungal spores’ ability to migrate, even after germination, through sandy layers demonstrates their potential to move up and down porous geological layers or rock fissures. Selective fungal affinity to specific wood in wood chip arrays might help differentiate viable anaerobic fungi from an anoxic environment for their rapid collection and investigation. New collection methods, cultivation, gene expression, and drug and enzyme activity analyses can boost anaerobic fungal research.

Graphical Abstract

Keywords:

• Anaerobic_fungi
• anoxic_habitats
• extremophiles
• microbial_ecology
• microbiome

Acknowledgments

The authors thank the late Prof. Dr. Nurul Islam of USTC for the Visiting Professorship given to E. Hoque. We thank D. Jurrat and G. Teichmann for their technical help and D. Klotz for the technical advice.

Geolocation information

We have performed this research work in Bavaria, Germany.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

We have included all the data involving this paper. We have deposited ITS1-ITS2 sequences of aquatic M. hiemalis f. hiemalis plus and minus strands in GenBank under the accession numbers GU183689 and GU183690, respectively.

Additional information

Funding

The USTC funded this research during Visiting Professorship to E. Hoque and by the IVAST (ivasthq.org), also previously funded by the Federal Government of Germany and the Bavarian State Government. J. Fritscher was funded by IVAST and previously by the mineral water company FRANKEN BRUNNEN GmbH & CoKG, Neustadt/Aisch, Bavaria, Germany.