Seven new Neocallimastigomycota genera from wild, zoo-housed, and domesticated herbivores greatly expand the taxonomic diversity of the phylum

ABSTRACT

We isolated and characterized 65 anaerobic gut fungal (AGF; Neocallimastigomycota) strains from fecal samples of five wild (W, axis deer, white-tailed deer, Boer goat, mouflon, and Nilgiri tahr), one zoo-housed (Z, zebra), and three domesticated (D,  horse, sheep, and goat) herbivores in the US states of Texas (TX) and Oklahoma (OK), Wales (WA), and the Indian states of Kerala (KE) and Haryana (HA). Phylogenetic assessment using the D1–D2 regions of the large subunit (28S) rDNA and internal transcribed spacer 1 (ITS1) identified seven monophyletic clades that are distinct from all currently recognized AGF genera. All strains displayed monocentric thalli and produced exclusively or predominantly monoflagellate zoospores, with the exception of axis deer strains, which produced polyflagellate zoospores. Analysis of amplicon-based AGF diversity surveys indicated that zebra and horse strains are representatives of uncultured AL1 group, whereas domesticated goat and sheep strains are representatives of uncultured AL5 group, previously encountered in fecal and rumen samples of multiple herbivores. The other five lineages, all of which were isolated from wild herbivores, have not been previously encountered in such surveys. Our results significantly expand the genus-level diversity within the Neocallimastigomycota and strongly suggest that wild herbivores represent a yet-untapped reservoir of AGF diversity. We propose seven novel genera and eight novel Neocallimastigomycota species to comprise these strains, for which we propose the names Agriosomyces longus (mouflon and wild Boer goat), Aklioshbomyces papillarum (white-tailed deer), Capellomyces foraminis (wild Boar goat), and C. elongatus (domesticated goat), Ghazallomyces constrictus (axis deer), Joblinomyces apicalis (domesticated goat and sheep), Khoyollomyces ramosus (zebra-horse), and Tahromyces munnarensis (Nilgiri tahr).

KEYWORDS:

• Anaerobic gut fungi
• herbivores
• Neocallimastigomycota
• 15 new taxa

ACKNOWLEDGMENTS

We thank Jim and Tammy Austin for providing fecal samples, Britny Johnson for technical assistance, Dr. Karthick Balasubramanian for his valuable help, the Oklahoma City Zoo for providing fecal samples, and the Kerala Forest Department, Munnar, for sampling permission (WL10-51713/2017).

Additional information

Funding

This work has been funded by the NSF-DEB grant 1557102 to N.H.Y. and M.S.E. and Department of Biotechnology (DBT) project no. BT/PR15694/PBD/26/506/2015 to S.S.D. T.M.C. is grateful to the Aberystwyth University Postgraduate Research Studentship Scheme for funding.