Systemic infection of Bryoria (Lecanoromycetes, Ascomycota) by Athelia (Agaricomycetes, Basidiomycota) in western North America

ABSTRACT

Bryoria (Parmeliaceae, Ascomycota) is one of the dominant genera of hair lichens in western North America and is characteristic of high-elevation conifer forest ecosystems. In areas where Bryoria is abundant, it is common to find thalli in which the thalline filaments become conglutinated, forming brittle dead zones. After sampling Bryoria thalli across western Canada and the northwestern United States at different times of the year, we found that this dieback phenomenon is associated with the winter growth of a mold-forming basidiomycete. We report that this fungus belongs to Athelia (Atheliaceae, Basidiomycota), a genus known to contain lichen pathogens, most notably A. arachnoidea. By sequencing a combination of genetic markers—nuc rDNA internal transcribed spacer region ITS1-5.8S-ITS2 (ITS), partial nuc 28S rDNA (28S), and partial translation elongation factor 1-α (TEF1)—paired with morphometric analyses, we reveal the involvement of at least three additional lineages of lichen-associated Athelia and describe one as a new species, A. abscondita. Athelia abscondita is morphologically distinguished from other Athelia species by its basidia and basidiospores, was found to frequently infect members of Bryoria sect. Implexae, and was occasionally on other foliose and fruticose species within Parmeliaceae.

KEYWORDS:

• Athelia
• Bryoria
• lichenicolous
• morphometrics
• phylogenetics
• 1 new taxon

Acknowledgments

We would like to thank Justine Karst who provided useful input at multiple stages of this project; Andrew Cook, David Díaz Escandón, and Gulnara Tagirdzhanova for their R prowess; Trevor Goward, Veera Tuovinen, Yngvar Gauslaa, and Curtis Björk for insightful conversations about lichen biology and physiology; Ross Evashkevich, Navodhi Ranatunga, and Purple for their field assistance; and Dr. Tanja Schuster (Naturhistorisches Museum Wien, Austria) who arranged a research visit for V.S. to herbarium W. An earlier version of this article was included in S.G.’s master’s thesis.

Disclosure statement

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

SUPPLEMENTARY MATERIAL

Supplemental data for this article can be accessed online at https://doi.org/10.1080/00275514.2023.2186679

Additional information

Funding

We gratefully acknowledge an NSERC Discovery Grant and Tier II Canada Research Chair to T.S. (Canada Research Chair in Symbiosis) and material funding from the Alberta Conservation Association (ACA) to S.G. in the form of an ACA Biodiversity Grant (RES0039387).