Electronic Theses and Dissertations

Date of Award

1-1-2024

Document Type

Dissertation

Degree Name

Ph.D. in Biological Science

First Advisor

Jason D. Hoeksema

Second Advisor

Cole Stevens

Third Advisor

Steve Brewer

School

University of Mississippi

Relational Format

dissertation/thesis

Abstract

The study of fungal traits is critical for understanding community assembly and ecosystem function, as traits related to resource acquisition, enemy avoidance, and stress tolerance link fungi to their ecological roles. Symbiotic relationships, such as those between ectomycorrhizal (EcM) fungi and their host plants, greatly influence fungal traits and play a key role in fungal evolution. In this study, we addressed the evolution of EcM fungal traits, particularly biosynthetic gene clusters (BGCs), at multiple genetic scales, including individual genes, genotypes within populations, and a broader phylogenetic perspective across the fungal kingdom. First, we surveyed the diversity of BGCs in native and introduced populations of Suillus luteus, examining both biogeographical patterns in BGC distribution and the evolutionary relationships among these clusters. Second, we investigated whether native and introduced fungal isolates show evidence of local adaptation to their host tree species and evaluated how the origin of these fungi impacts the performance of their host trees. Finally, we explored the association between the proportions and abundances of different BGC classes and specific fungal lifestyles and lineages. Our findings revealed several key results. We observed higher BGC diversity in native populations of S. luteus, identified 24 highly conserved BGC clans, and confirmed the presence of three distinct clades, indicating that the introduction of S. luteus has led to evolutionary changes in its BGCs. We also found evidence of local maladaptation in native and introduced S. luteus fungal isolates, with allopatric fungal isolates showing better performance metrics compared to sympatric. This highlights the complexity of coevolution and the importance of considering both adaptation and maladaptation in species interactions. Finally, we found that specific BGC classes exhibit notable phylogenetic signals and that BGC abundance varies with fungal lifestyles, indicating that both phylogenetic history and ecological strategies influence BGC distribution. Overall, our study provides insights into fungal community ecology and the evolutionary processes shaping their biosynthetic potential.

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