Cool season grasses host multiple fungal symbionts, such as aboveground Epichloë endophytes and belowground arbuscular mycorrhizal fungi (AMF) and dark septate endophytes (DSEs). Asexual Epichloë endophytes can influence root colonization by AMF, but the type of interaction—whether antagonistic or beneficial—varies. In Schedonorus arundinaceus (tall fescue), Epichloë coenophiala can negatively affect AMF, which may impact soil properties and ecosystem function. Within field plots of S. arundinaceus that were either E. coenophiala-free (E−), infected with the common, mammal-toxic E. coenophiala strain (CTE+), or infected with one of two novel, non-toxic strains (AR542 NTE+ and AR584 NTE+), we hypothesized that (1) CTE+ would decrease AMF and DSE colonization rates and reduce soil extraradical AMF hyphae compared to E− or NTE+, and (2) this would lead to E− and NTE+ plots having greater water stable soil aggregates and C than CTE+. E. coenophiala presence and strain did not significantly alter AMF or DSE colonization, nor did it affect extraradical AMF hypha length, soil aggregates, or aggregate-associated C and N. Soil extraradical AMF hypha length negatively correlated with root AMF colonization. Our results contrast with previous demonstrations that E. coenophiala symbiosis inhibits belowground AMF communities. In our mesic, relatively nutrient-rich grassland, E. coenophiala symbiosis did not antagonize belowground symbionts, regardless of strain. Manipulating E. coenophiala strains within S. arundinaceus may not significantly alter AMF communities and nutrient cycling, yet we must further explore these relationships under different soils and environmental conditions given that symbiont interactions can be important in determining ecosystem response to global change.
|Number of pages||10|
|State||Published - Oct 1 2016|
Bibliographical noteFunding Information:
Lindsey C. Slaughter was supported by the UK Department of Plant and Soil Sciences. The authors thank J. Nelson and E. Carlisle for field maintenance and assistance, J. Crutchfield for plant N and P analysis, and K. Jacobsen for soil aggregate analysis equipment. We thank Sarah Hall (Berea College) for training in AMF colonization, and Dan Weber and Eric Kalosa-Kenyon for harvest assistance. We appreciate the Noble Foundation for providing S. arundinaceus seed and endophyte genetic assessments, and UK Regulatory Services Soil Testing Lab for soil nutrient characterization. This field project was supported by the Kentucky Agricultural Experiment Station (KY006045) and a cooperative agreement between UK’s College of Agriculture, Food, and the Environment and the USDA-ARS-Forage Animal Production Research Unit (Award No. 58-6440-7-135).
© 2016, Springer Science+Business Media New York.
- Arbuscular mycorrhizal fungi
- Carbon sequestration
- Dark septate endophytes
- Tall fescue
ASJC Scopus subject areas
- Ecology, Evolution, Behavior and Systematics
- Soil Science