Abstract Detail

Mycology

Muniania, Cedric Ndinga [1], Worson, Nick [1], Borer, Elizabeth [1], Seabloom, Eric [1], Kinkel, Linda [2], May, Georgiana [3].

Anthropogenic nutrient inputs shift ecological interactions and structure of endophytic fungal symbiont communities.

Human activities are altering the supply of nutrients to ecosystems with implications for organismal function and interactions. Despite the critical importance of endophytic fungal (EF) communities to the functioning of plant hosts, the impact of nutrient supply on EF communities, and their functional traits is not well understood. In this study, we used both phylogenetic and trait-based approaches to evaluate the impacts of nutrient amendment on EF community diversity, assembly, and interactions among these fungi. We hypothesized that nutrient amendment reduces EF diversity and increases the growth of more competitive EF species, and that competition is the main process driving EF community assembly. Using an existing long-term Nutrient Network experimental site at the UMN Cedar Creek Ecosystem Science Reserve, we sampled A. gerardii leaves from replicate plots in which plant mineral nutrients (Nitrogen, Phosphorous and Potassium; NPK) had been added or not, in control plots. EF were isolated using two different methods from each sampled leaf and consisted of leaf sectioning and maceration, and ITS1 rDNA sequences were obtained for all isolates (n = 672). We compared taxon richness, composition and the phylogenetic structure of EF communities from leaves sampled from NPK and control plots and resulting from the two isolation methods. To evaluate EF functional traits, we measured growth on 95 carbon substrates using Biolog SF-P2 resource plates for randomly selected isolates from each sampled leaf, and used these to estimate EF community trait-based structure and niche overlap, an index of competition among EF isolates. Our results showed that isolation methods generated two, previously undescribed and phylogenetically distinct EF communities that apparently differ in their growth and resource use patterns. The evaluation of EF community phylogenetic structures revealed phylogenetic clustering and suggested a role of habitat filtering in structuring communities. In contrast, depending on the trait evaluated, community trait-based analysis showed evidence of trait clustering or overdispersion, suggesting a role for both habitat filtering and competition in structuring communities. Further, although EF richness did not differ significantly across plots due to NPK treatments, both EF community composition and the extent of niche overlap among EF isolates shifted with NPK treatment. Together, our results suggest that both habitat filtering and competition play important roles in the assembly of the EF communities and that changes in EF community composition in response to nutrient amendment is associated with EF species’ functional traits and competitive interactions among them.

1 - University of Minnesota, 1479 Gortner Avenue, 140 Gortner Laboratory, Saint Paul, Minnesota, 55108, United States
2 - University of Minnesota, Plant Pathology, 1479 Gortner Avenue, 140 Gortner Laboratory, Saint Paul, Minnesota, 55108, United States
3 - University of Minnesota, Ecology, Evolution and Behavior, 140 Gortner Laboratory, 1479 Gortner Avenue, Saint Paul, MN, 55108, USA

Keywords:
endophytic fungi
Communiy assembly
Trait-based structure
Phylogenetic clustering
Nutrient addition
Andropogon gerardii
Mycology.

Presentation Type: Oral Paper
Session: MY1, Mycology: Ecology and Conservation
Location: /
Date: Monday, July 19th, 2021
Time: 11:45 AM(EDT)
Number: MY1004
Abstract ID:936
Candidate for Awards:MSA Best Oral Presentation Award by a Graduate Student