Microbial communities as indicators of ecosystem functions at two sites in Great Smoky Mountains National Park

WCU Author/Contributor (non-WCU co-authors, if there are any, appear on document)
Elin Richard Swank (Creator)
Western Carolina University (WCU )
Web Site: http://library.wcu.edu/
Sean O'Connell

Abstract: Differences in soil nutrient cycling, including nitrogen cycling and bioavailability have been linked to the inhabiting microbial and plant community interactions (Powell et al., 2015; Levy-Booth et al., 2014). Understanding the community relationships and their effects may help us describe the role of microbial communities in influencing plant communities and ecosystem functions (Phillips et al., 2013; Isobe et al., 2011; Hacquard and Schadt, 2015). Data quality (accurate, informative etc.) and quantity is needed to describe causal relationships among microbial communities, plant communities, and their distributions in an ecosystem (Mushinski et al., 2017). To address the need for and demonstrate the utility of, functional and process focused data, microbial community analysis was conducted focusing on known bacterial nitrogen cyclers and mycorrhizal fungi. Samples were cored from the mineral soil within the mycorrhizosphere surrounding a Northern Red Oak (Quercus rubra) at both the Purchase Knob (35.59173°N, 83.05997°W) and Cataloochee (35.58760°N, 83.08064°W) All Taxa Biodiversity Inventory (ATBI) plots (n=12 from each site). Samples were pooled and homogenized by sub-site location around the oak tree at each site (up slope, side slope, down slope; n=3 from each site). DNA extraction and next generation sequencing of the bacterial 16S rRNA and fungal internal transcribed spacer (ITS) rRNA regions were performed by Azenta, Inc. (South Plainfield, NJ). Important bacterial genera found include the metabolically diverse Burkholderia, as well as known participants in soil nitrogen cycling Nitrospira, Bradyrhizobium, Rhodoplanes, and Pedomicrobium. Ectomycorrhizal (ECM) fungi genera that are important plant symbionts and transporters of nutrients within soil (Allen et al., 2003; Churchland and Grayston, 2014) were found, including Sebacina, Russula, Elaphomyces and the potentially ECM Pseudotricholoma. Principal components analysis (PCA) of the distributions of sequences showed a clear difference between the Cataloochee and Purchase Knob site samples with greater variability in sample community composition at Cataloochee for both bacteria and fungi. Key and prevalent groups identified are known to be involved in nitrogen cycling, plant associations, and nutrient transport suggesting that their relationships play some role in biogeochemical and nutrient cycling. Future analyses are needed to describe the pathways between microbial and plant, taxa and communities, and the emergent properties relating them to nutrient cycling and ecosystem functions. Supplementary files include the files 16S_otu_taxa_table.csv (bacteria dataset), ITS_otu_taxa_table.csv (fungi dataset), MIDI_Functional_Genes.csv (functional gene dataset), Figures_Tables.pdf (data tables and visualizations) and Figures_Tables.Rmd (R markdown script used to create Figures_Tables.pdf). The raw sequence files for next generation sequencing of bacterial 16S rRNA and fungal ITS regions are available through the National Center for Biotechnology Information (NCBI) at https://www.ncbi.nlm.nih.gov/bioproject/978337 with accession numbers SAMN35549206-SAMN35549229.

Additional Information

Language: English
Date: 2023
Microbial ecology
Plant-microbe relationships
Nitrogen cycle
Quercus rubra

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