Abstract Detail

Mycology

Mafune, Korena [1], Godfrey, Bruce [2], Vogt, Kristiina [3], Vogt, Daniel [3].

Root-associated fungi in canopy soil environments of old-growth Acer macrophyllum are distict from those in forest floor rooting systems and community diversity is impacted by seasonal extremes.

In Washington's temperate rainforests, old-growth bigleaf maple trees (Acer macrophyllum Pursh.) can host copious amounts of organic canopy soil on branches, often reaching depths >35 cm. These canopy soils have higher concentrations of plant available nitrogen (N) and phosphorus (P) than forest floor soils, and provide habitat to a broad diversity of organisms. However, the ecological role of the canopy soil environment is often overlooked when considering how these old-growth trees may respond to seasonal extremes (e.g., wetter winters and drier summers). It becomes important to explore biotic interactions in canopy soils, especially because old-growth bigleaf maples form extensive adventitious roots that associate with fungal organisms. However, until this study, the root-associated fungal community diversity and dynamics remained widely unexplored in both canopy and forest floor soil environments. Therefore, this research aimed to explore the diversity of root-associated fungi in canopy and forest floor soils of old-growth bigleaf maple trees, and further test if root-associated fungal community composition was impacted by higher or lower precipitation conditions. To execute this study, 12 old-growth bigleaf maple trees were selected in the Queets and Hoh temperate rainforests. At the canopy soil level, an experiment was implemented that manipulated the amount of precipitation intercepted on a canopy soil branch. Four trees had roof-interception structures that diverted 1/2x of precipitation from reaching the canopy soil, four trees had an irrigation system that increased the amount of precipitation by two-fold, and four trees were left at ambient conditions for comparison. Fine roots were collected from the canopy and forest floor soil environments in Spring 2018, Summer 2018, Fall 2018, and Spring 2019. Fungal DNA was extracted, amplified, and sequenced on both the MinION Nanopore Sequencer and Illumina MiSeq. At ambient conditions, root-associated fungal communities in canopy soils are significantly different from the those associating with forest floor roots (p ≤ 0.01), but seasonality did not have an effect on root-associated community diversity. At the canopy soil level, the precipitation treatments and seasonality impacted root-associated fungal community diversity (p ≤ 0.01). There were species identified from adventitious canopy roots that have never been reported to associate with bigleaf maple before, including potentially mutualistic dark septate endophytes. Seasonality did not have an effect on root-associated fungal community composition at ambient conditions, but did have an effect across the experimental manipulations. This suggests that root-associated fungal communities in canopy soils may be acting as adaptive facilitators to environmental extremes.

1 - University of Washington, School of Environmental and Forest Science, Box 352100, Seattle, WA, 98195-2100, USA
2 - University of Washington, Department of Civil and Environmental Engineering, Seattle, WA, 98195-2100, United States
3 - University of Washington, School of Environmental and Forest Science, Box 352100, Seattle, WA, 98195-2100, United States

Keywords:
Fungal communities
plant-fungal interactions
Canopy soils
mycorrhizal fungi
temperate rainforests
Fungal diversity
Mycology.

Presentation Type: Oral Paper
Session: MY4, Mycology: Endophytes, Communities, Hydrophobins, and Transporters
Location: /
Date: Wednesday, July 21st, 2021
Time: 2:00 PM(EDT)
Number: MY4007
Abstract ID:834
Candidate for Awards:MSA Best Oral Presentation Award by a Graduate Student