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Paez, Carolina Pina [1], Carson, Adam [2], Luoma, Daniel [2], Spatafora, Joseph [3].

Truffles in the sky: the impact of stochastic and deterministic drivers on Rhizopogon communities of the Madrean Sky Island Archipelago.

The Madrean Sky Islands Archipelago (MSIA) is situated between the Rocky Mountains and the Sierra Madre and is comprises mountain “islands” whose Pine-Oak forests appear in stark contrast to the surrounding “sea” of Sonoran Desert vegetation. Rhizopogon is a diverse genus in the order Boletales and consists of obligate ectomycorrhizal (EcM) symbionts that associate exclusively with Pinaceae species. The general objectives of this project are to describe the diversity of species of Rhizopogon across the sky islands and characterize the impact of geographic isolation on Rhizopogon communities. Nine islands across the MSIA were selected. Two sites were sampled per island: one site dominated by Pinus species and the other by Pseudotsuga menziesii var. glauca. Three transects separated by 25 meters were established at each site, and six stops separated by 20 meters were made per transect for a total of 18 sample points per site. We searched for sporocarps for 2o minutes at each stop, then collected a soil sample. Sporocarps were photographed and air-dried for use in DNA extractions. Soil samples were used in bioassay-based sampling with P. muricata, Ps. menziesii var. menziesii, and Ps. menziesii var. glauca as host trees. EcM root tips were dissected for DNA extraction six months post-inoculation. The ITS rDNA fungal barcode was amplified and sequenced for all sporocarp collections and EcM root tips. ITS sequences were appended to a reference dataset of known sequences and analyzed phylogenetically. Twenty-one OTUs were identified, R. salebrosus 1 was the most widespread species, present in all the mountain ranges. In contrast, R. fuscorubens and R. truncatus were restricted to Santa Catalina, and R. granuloflavous was only found in Elenita. Our results support that while differential host association with Pinus and Pseudotsuga is a significant driver of community composition, Rhizopogon communities associated within hosts are characterized by random phylogenetic structures across sky islands and are not structured by geographic distance. These results are consistent with a strong island effect, and that both niche partitioning (host association) and neutral (random) processes function in shaping Rhizopogon communities of the MSIA.

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1 - Oregon State University, Botany and Plant Pathology, Research Way Laboratory Building, 4575 SW Research Way, Corvallis, OR, 97333, USA
2 - Oregon State University, Research Way Laboratory Building, 4575 SW Research Way, Corvallis, OR, 97333, United States
3 - Department Of Botany & Plant Pathology, 2082 Cordley Hall, Corvallis, OR, 97331, United States

Ectomycorrhizal fungi
Communiy assembly

Presentation Type: Poster
Session: MYP2, Mycology Posters II
Location: Virtual/Virtual
Date: Tuesday, July 20th, 2021
Time: 5:00 PM(EDT)
Number: MYP2009
Abstract ID:1053
Candidate for Awards:MSA Best Poster Presentation Award by a Graduate Student

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