Bifiguratus adelaidae, gen. et sp. nov., a new member of Mucoromycotina in endophytic and soil-dwelling habitats

ABSTRACT

Illumina amplicon sequencing of soil in a temperate pine forest in the southeastern United States detected an abundant, nitrogen (N)-responsive fungal genotype of unknown phylogenetic affiliation. Two isolates with ribosomal sequences consistent with that genotype were subsequently obtained. Examination of records in GenBank revealed that a genetically similar fungus had been isolated previously as an endophyte of moss in a pine forest in the southwestern United States. The three isolates were characterized using morphological, genomic, and multilocus molecular data (18S, internal transcribed spacer [ITS], and 28S rRNA sequences). Phylogenetic and maximum likelihood phylogenomic reconstructions revealed that the taxon represents a novel lineage in Mucoromycotina, only preceded by Calcarisporiella, the earliest diverging lineage in the subphylum. Sequences for the novel taxon are frequently detected in environmental sequencing studies, and it is currently part of UNITE’s dynamic list of most wanted fungi. The fungus is dimorphic, grows best at room temperature, and is associated with a wide variety of bacteria. Here, a new monotypic genus, Bifiguratus, is proposed, typified by Bifiguratus adelaidae.

KEYWORDS:

• Bryophyte
• dimorphic
• endophyte
• environmental sampling
• Mucoromycota
• Pinaceae
• soil

ACKNOWLEDGMENTS

Isolation and sequencing of AZ0501 were supported by the efforts of Jana U’Ren, Jolanta Miadlikowska, François Lutzoni, Alex Laetsch, Fabiola Santos, and Ester Gaya. The authors thank Arthur Thompson (National Center for Agricultural Utilization Research, Peoria, Illinois) for generating the SEM images and Adrian Tsang (Concordia University) for access to the Calcarisporiella thermophila genome.

The type species described here was named in honor of Adelaida Chaverri Polini. Dr. Chaverri was a world-recognized tropical biologist and role model for women in Latin America in science, technology, engineering, and mathematics. Her major contributions were in the study and conservation of tropical montane forests and treeless alpine grasslands (páramos). As a biologist, she recognized the importance of mycorrhizal fungi and contributed to the description of a fungus in the Acaulosporaceae, a fungus in the same phylum as the species described here (Sieverding et al. 1988). She supported the creation of Costa Rica’s National Park Service, providing the basis for extensive conservation of biological diversity. In 2013, she was included in the Galería de la Mujer (Women Gallery), one of the highest honors given to Costa Rican women for their dedication to defending and improving women human rights (Kappelle and Cleef 2004).

FUNDING

This study was supported through a Science Focus Area grant to C.R.K. from the U.S. Department of Energy, Biological and Environmental Research Division. T.J.T.-C. thanks the RISE (Research Inspiring Student Excellence) and Women in Science programs at Western Illinois University for research support. G.M.N.B., A.D., and G.B. thank Michigan State University AgBioResearch and U.S. Department of Agriculture for research support. Isolation and sequencing of AZ0501 were supported by financial support from the College of Agriculture and Life Sciences at The University of Arizona, National Science Foundation (NSF) DEB-0640996 to A.E.A., and DEB-0640956 to François Lutzoni. J.E.S. was supported by NSF DEB-1441715 and high-performance computing resources at the Institute for Integrative Genome Biology at University of California–Riverside supported by NSF DBI-1429826 and National Institutes of Health (NIH) S10-OD016290.

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