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Abstract Plant colonization of islands may be limited by the availability of symbionts, particularly arbuscular mycorrhizal (AM) fungi, which have limited dispersal ability compared to ectomycorrhizal and ericoid (EEM) as well as orchid mycorrhizal (ORC) fungi. We tested for such differential island colonization within contemporary angiosperm floras worldwide. We found evidence that AM plants experience a stronger mycorrhizal filter than other mycorrhizal or non-mycorrhizal (NM) plant species, with decreased proportions of native AM plant species on islands relative to mainlands. This effect intensified with island isolation, particularly for non-endemic plant species. The proportion of endemic AM plant species increased with island isolation, consistent with diversification filling niches left open by the mycorrhizal filter. We further found evidence of humans overcoming the initial mycorrhizal filter. Naturalized floras showed higher proportions of AM plant species than native floras, a pattern that increased with increasing isolation and land-use intensity. This work provides evidence that mycorrhizal fungal symbionts shape plant colonization of islands and subsequent diversification.
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This content will become publicly available on June 1, 2026
A phylogenetic study of the Cantharellales supports recognition of four families and independent gains of biotrophic nutritional modes
Abstract PremiseThe agaricomycete order Cantharellales contains approximately 1000 species of fungi characterized by diverse morphological forms, ecological guilds, and nutritional modes. Examples include coralloid lichens that form symbioses with unicellular green algae, bulbil‐forming lichenicolous species, corticioid free‐living fungi that degrade dead sources of organic carbon, pathogens that cause plant disease, orchid root endosymbionts, and ectomycorrhizal fungi including popular edible mushrooms. However, evolutionary relationships in the Cantharellales remain poorly understood due to conflicting estimates based on ribosomal DNA loci. MethodsWe constructed a five‐gene phylogeny of the Cantharellales using data from 301 specimens to evaluate family‐level relationships. We used penalized likelihood to estimate divergence times and ancestral state reconstruction to test the hypothesis of multiple independent origins of biotrophic ecologies in the order and whether those transitions are younger than the divergence times of associated plant or lichen hosts. ResultsFour monophyletic families were recovered with strong support: Botryobasidiaceae, Ceratobasidiaceae, Hydnaceae s.l., and Tulasnellaceae, with Hydnaceae containing the greatest species richness and morphological diversity. Our results suggest the Cantharellales diverged during the Carboniferous period with subsequent diversification following the Permian‐Triassic extinction. Ancestral state reconstruction supports a saprotrophic most recent common ancestor with at least three transitions to an ectomycorrhizal ecology, multiple transitions to a lichenicolous habit with one or more subsequent transitions to mutualistic nutritional modes, four transitions to an orchid mycorrhizal ecology, and two transitions to a lichenized lifestyle. ConclusionsThis study represents the first comprehensive examination of the evolution of form and function across this ecologically and morphologically diverse order of fungi.
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- Award ID(s):
- 2030779
- PAR ID:
- 10623939
- Publisher / Repository:
- Botanical Society of America
- Date Published:
- Journal Name:
- American Journal of Botany
- Volume:
- 112
- Issue:
- 6
- ISSN:
- 0002-9122
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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