An official website of the United States government
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.
more »
« less
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.
more »
« less
- 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
More Like this
-
-
The damselflies Hetaerininae, a subfamily of Calopterygidae, comprise four genera distributed from North to South America: Hetaerina, Mnesarete, Ormenophlebia and Bryoplathanon. While several studies have focused on the intriguing behavioral and morphological modifications within Hetaerina, little of the evolutionary history of the group is well understood. Understanding the biogeographical history of Hetaerininae is further complicated by uncertainty in important geological events, such as the closure of the Central American Seaway (CAS). We generated a phylogenetic hypothesis to test the relationships and divergence times within Hetaerininae using IQtree and BEAST2 and found that Mnesarete and Ormenophlebia render Hetaerina paraphyletic. Reclassification of the genera within Hetaerininae is necessary based on our results. We also tested the fit to our dataset of two different hypotheses for the closure of CAS. Our results supported a gradual closure, starting in the Oligocene and ending in the Pliocene. Using Ancestral Character State Reconstruction, we found that the rubyspot, which is associated with higher fecundity in several species, was ancestral for Hetaerininae and subsequently lost four times. Estimates of diversification in association with the rubyspot are needed to understand the plasticity of this important character. Forest habitat was the ancestral state for Hetaerininae, with transitions to generalist species of Hetaerina found primarily in the Mesoamerican region. These results add to our understanding of the relationship between morphology, biogeography and habitat in a charismatic group of damselflies.more » « less
-
Summary Arbuscular mycorrhizal fungi (AMF) are critical to native plant community ecology and influence plant invasions. Research has focused on nutritional benefits of AMF, although evidence shows that they may also confer pathogen resistance. However, most such work has focused on agriculturally relevant plant species. Therefore, whether AMF confer pathogen resistance tonative(wild) plant species, and impact of novel plant–microbial relationships on this benefit, remains understudied.We conducted a series of experiments measuring mycorrhizal‐induced resistance (MIR) to pathogens in native prairie plant species. We tested for pathogenicity across 69 field‐isolated fungi and oomycetes across five plant species. We then conducted experiments assessing growth response to native and non‐native AMF and pathogens in three plant species from native populations and milkweed (Asclepias syriaca) from native and postagricultural populations.We found evidence of MIR in milkweed. Moreover, we identified differential effects of AMF depending on plant species, with milkweed from native populations showing benefits from AMF. Finally, growth response was mediated by local adaptation, with matching AMF–pathogen origin strengthening responses.This work illustrates the importance of locally sourced AMF and plants to native plant ecology and suggests that pathogen resistance may be an important dimension of AMF benefit.more » « less
-
PremiseUnderstanding relationships among orchid species and populations is of critical importance for orchid conservation. Target sequence capture has become a standard method for extracting hundreds of orthologous loci for phylogenomics. Up‐front cost and time associated with design of bait sets makes this method prohibitively expensive for many researchers. Therefore, we designed a target capture kit to reliably sequence hundreds of orthologous loci across orchid lineages. MethodsWe designed an Orchidaceae target capture bait set for 963 single‐copy genes identified in published orchid genome sequences. The bait set was tested on 28 orchid species, with representatives of the subfamilies Cypripedioideae, Orchidoideae, and Epidendroideae. ResultsBetween 1,518,041 and 87,946,590 paired‐end 150‐base reads were generated for target‐enriched genomic libraries. We assembled an average of 812 genes per library for Epidendroideae species and a mean of 501 genes for species in the subfamilies Orchidoideae and Cypripedioideae. Furthermore, libraries had on average 107 of the 254 genes that are included in the Angiosperms353 bait set, allowing for direct comparison of studies using either bait set. DiscussionThe Orchidaceae963 kit will enable greater accessibility and utility of next‐generation sequencing for orchid systematics, population genetics, and identification in the illegal orchid trade.more » « less
-
Mycorrhizal fungi are critical members of the plant microbiome, forming a symbiosis with the roots of most plants on Earth. Most plant species partner with either arbuscular or ectomycorrhizal fungi, and these symbioses are thought to represent plant adaptations to fast and slow soil nutrient cycling rates. This generates a second hypothesis, that arbuscular and ectomycorrhizal plant species traits complement and reinforce these fungal strategies, resulting in nutrient acquisitive vs. conservative plant trait profiles. Here we analyzed 17,764 species level trait observations from 2,940 woody plant species to show that mycorrhizal plants differ systematically in nitrogen and phosphorus economic traits. Differences were clearest in temperate latitudes, where ectomycorrhizal plant species are more nitrogen use- and phosphorus use-conservative than arbuscular mycorrhizal species. This difference is reflected in both aboveground and belowground plant traits and is robust to controlling for evolutionary history, nitrogen fixation ability, deciduousness, latitude, and species climate niche. Furthermore, mycorrhizal effects are large and frequently similar to or greater in magnitude than the influence of plant nitrogen fixation ability or deciduous vs. evergreen leaf habit. Ectomycorrhizal plants are also more nitrogen conservative than arbuscular plants in boreal and tropical ecosystems, although differences in phosphorus use are less apparent outside temperate latitudes. Our findings bolster current theories of ecosystems rooted in mycorrhizal ecology and support the hypothesis that plant mycorrhizal association is linked to the evolution of plant nutrient economic strategies.more » « less
