Honors Program

Midway Honors, Honors in Biology

Date of Award


Thesis Professor(s)

Dr. Gerardo Arceo-Gomez

Thesis Professor Department

Biological Sciences

Thesis Reader(s)

Dr. Cecilia A. McIntosh


Plant nectar microbiome, primarily consisting of fungi and bacteria, can qualitatively and quantitively alter the floral rewards by exploiting the chemical composition of the nectar which can thus impact plant-pollinator interactions, and ultimately affect plant reproductive success. Evidence suggests that changes in the microenvironmental conditions across various spatial gradients can induce changes in the floral nectar microbiome, which can account for microbial variation not only across plant species, but also within. Furthermore, nectar microbiome is also contingent on the pollinator systems and nectar quality. In this study, we used Rhododendron catawbiense (bee-pollinated; highly toxic nectar) and Lobelia cardinalis (hummingbird-pollinated; mildly toxic nectar) to explore the so-far unknown composition, diversity, and abundance of the nectar mycobiome across the spatial gradients of elevation and distance, respectively. It was done in the native Appalachian region of East Tennessee to improve the understanding of the microbiome-pollinator dynamics so that biodiversity can be better preserved. Through field sample collection, nectar harvesting, plating, isolation, DNA extraction, and Sanger Sequencing, we found that there were significant differences in terms of fungal abundance within the R. catawbiense and L. cardinalis species. Across plant species, R. catawbiense had more fungal abundance, attributable to being bee pollinated. L. cardinalis had more fungal diversity, attributable to its relatively low nectar toxicity. The results of Species Richness and Simpson’s Diversity, however, were found to be not significantly different in every instance. Furthermore, the plant species only shared two fungal species in common, with others also being unique to either an elevation or location, suggesting a high fungal species-plant species-spatial variation specificity.


East Tennessee State University

Document Type

Honors Thesis - Withheld

Creative Commons License

Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 License.


Copyright by the authors.

Available for download on Tuesday, May 09, 2023

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