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 relative Andropogon cover, endophyte diversity did not covary with live plant biomass or Andropogon cover. 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.
| Original language | English (US) |
|---|---|
| Article number | e03210 |
| Journal | Ecology |
| Volume | 102 |
| Issue number | 1 |
| DOIs | |
| State | Published - Dec 1 2020 |
Bibliographical note
Funding Information:This work was supported by grants to E. T. Borer and E. W. Seabloom from the U.S. National Science Foundation including MSB-1241895, DEB-1556649, and DEB-1234162. Support also was provided by the US National Science Foundation Long-Term Ecological Research (LTER) Program (DEB-1234162 and DEB-1831944), Cedar Creek Ecosystem Science Reserve, and the Minnesota Supercomputer Institute, and the University of Minnesota. We would like to thank Ashley Asmus, Bradford Condon, Anita Porath-Krause, Zewei Song, Alex Strauss, and Chris Walter for valuable input on previous drafts of this manuscript, bioinformatics, and aiding in data collection. Additionally, we would like to thank Megan Wilcots and Katie Schroeder for providing unpublished seasonal plant community data collected during the 2019 growing season. Finally, Authors would like to thank two anonymous reviewers whose contributions have strengthened our final manuscript. E. Borer and E. Seabloom designed and implemented the Nutrient Network field experiment. E. T. Borer, E. W. Seabloom, L. Kinkel, C. Y. Lumibao, and G. May conceived the ideas and designed methodology for the fungal sampling, C. Y. Lumibao performed DNA extractions, barcoding, and bioinformatics. J. A. Henning, E. T. Borer, and E. W. Seabloom conceived the ideas and hypotheses, J. A. Henning performed the statistical analyses and led the writing of the manuscript with contribution by all coauthors on subsequent drafts and gave final approval for publication.
Funding Information:
This work was supported by grants to E. T. Borer and E. W. Seabloom from the U.S. National Science Foundation including MSB‐1241895, DEB‐1556649, and DEB‐1234162. Support also was provided by the US National Science Foundation Long‐Term Ecological Research (LTER) Program (DEB‐1234162 and DEB‐1831944), Cedar Creek Ecosystem Science Reserve, and the Minnesota Supercomputer Institute, and the University of Minnesota. We would like to thank Ashley Asmus, Bradford Condon, Anita Porath‐Krause, Zewei Song, Alex Strauss, and Chris Walter for valuable input on previous drafts of this manuscript, bioinformatics, and aiding in data collection. Additionally, we would like to thank Megan Wilcots and Katie Schroeder for providing unpublished seasonal plant community data collected during the 2019 growing season. Finally, Authors would like to thank two anonymous reviewers whose contributions have strengthened our final manuscript. E. Borer and E. Seabloom designed and implemented the Nutrient Network field experiment. E. T. Borer, E. W. Seabloom, L. Kinkel, C. Y. Lumibao, and G. May conceived the ideas and designed methodology for the fungal sampling, C. Y. Lumibao performed DNA extractions, barcoding, and bioinformatics. J. A. Henning, E. T. Borer, and E. W. Seabloom conceived the ideas and hypotheses, J. A. Henning performed the statistical analyses and led the writing of the manuscript with contribution by all coauthors on subsequent drafts and gave final approval for publication.
Publisher Copyright:
© 2020 by the Ecological Society of America
Keywords
- Andropogon
- NutNet
- biodiversity
- foliar endophytes
- fungi
- nitrogen
- nutrient addition
- nutrient network
- phosphorus