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Abstract Foliar fungal endophytes are ubiquitous plant symbionts that can affect plant growth and reproduction via their roles in pathogen and stress tolerance, as well as plant hormonal signaling. Despite their importance, we have a limited understanding of how foliar fungal endophytes respond to varying environmental conditions such as nutrient inputs. The responses of foliar fungal endophyte communities to increased nutrient deposition may be mediated by the simultaneous effects on within‐host competition as well as the indirect impacts of altered host population size, plant productivity, and plant community diversity and composition. Here, we leveraged a 7‐yr experiment manipulating nitrogen, phosphorus, potassium, and micronutrients to investigate how nutrient‐induced changes to plant diversity, plant productivity, and plant community composition relate to changes in foliar fungal endophyte diversity and richness in a focal native grass host,Andropogon gerardii. We found limited evidence of direct effects of nutrients on endophyte diversity. Instead, the effects of nutrients on endophyte diversity appeared to be mediated by accumulation of plant litter and plant diversity loss. Specifically, nitrogen addition is associated with a 40% decrease in plant diversity and an 11% decrease in endophyte richness. Although nitrogen, phosphorus, and potassium addition increased aboveground live biomass and decreased relativeAndropogoncover, endophyte diversity did not covary with live plant biomass orAndropogoncover. Our results suggest that fungal endophyte diversity within this focal host is determined in part by the diversity of the surrounding plant community and its potential impact on immigrant propagules and dispersal dynamics. Our results suggest that elemental nutrients reduce endophyte diversity indirectly via impacts on the local plant community, not direct response to nutrient addition. Thus, the effects of global change drivers, such as nutrient deposition, on characteristics of host populations and the diversity of their local communities are important for predicting the response of symbiont communities in a changing global environment.
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Cryptic functional diversity within a grass mycobiome
Eukaryotic hosts harbor tremendously diverse microbiomes that affect host fitness and response to environmental challenges. Fungal endophytes are prominent members of plant microbiomes, but we lack information on the diversity in functional traits affecting their interactions with their host and environment. We used two culturing approaches to isolate fungal endophytes associated with the widespread, dominant prairie grassAndropogon gerardiiand characterized their taxonomic diversity using rDNA barcode sequencing. A randomly chosen subset of fungi representing the diversity of each leaf was then evaluated for their use of different carbon compound resources and growth on those resources. Applying community phylogenetic analyses, we discovered that these fungal endophyte communities are comprised of phylogenetically distinct assemblages of slow- and fast-growing fungi that differ in their use and growth on differing carbon substrates. Our results demonstrate previously undescribed and cryptic functional diversity in carbon resource use and growth in fungal endophyte communities ofA.gerardii.
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- Award ID(s):
- 1831944
- PAR ID:
- 10478464
- Editor(s):
- Chiang, Tzen-Yuh
- Publisher / Repository:
- PLOS
- Date Published:
- Journal Name:
- PLOS ONE
- Volume:
- 18
- Issue:
- 7
- ISSN:
- 1932-6203
- Page Range / eLocation ID:
- e0287990
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1371/journal.pone.0287990
