Year

2024

Season

Spring

Paper Type

Master's Thesis

College

College of Arts and Sciences

Degree Name

Master of Science in Biology (MS)

Department

Biology

NACO controlled Corporate Body

University of North Florida. Department of Biology

First Advisor

Dr. Anthony Rossi

Second Advisor

Dr. Dale Casamatta

Third Advisor

Dr. Keith Stokes

Department Chair

Dr. Cliff Ross

Abstract

Asphondylia borrichiae, like other gall-forming gnats, are obligate symbionts to the endophytic fungi (EF) they deposit when laying eggs. Asphondylia spp. and EF are important biocontrol agents, yet details surrounding their diversity, life cycles, and host interactions remain poorly understood. Galls and leaf-stem tissues from two host plants were surveyed to identify and compare EF diversity between the host tissues and species of A. borrichiae. Identification of 114 isolates was carried out by sequencing the internal transcribed spacer (ITS 1/4 primers). Pairwise alignments in multiple genetic databases were bolstered by phylogenetic analyses using maximum parsimony and maximum likelihood for bootstrapping support. A total of 21 genera were identified. The most prominent genus was Fusarium, particularly those within the Fusarium incarnatum-equiseti species complex (FIESC). Galls included species previously documented in A. borrichiae galls: Botryosphaeria dothidea, Cladosporium spp., and Alternaria alternata. Several genera were isolated that have not been previously identified in A. borrichiae galls: Clonostachys rosea, Sarocladium sp., Daldinia sp., Nigrospora spp., Hypoxylon sp., Epicoccum sp., Curvularia sp., Trichoderma sp., Pestalotiopsis sp., and Phlebiopsis sp. Diversity index values of EF communities between B. frutescens and I. frutescens galls were significantly different, with greater diversity observed in B. frutescens galls. Similarities of EF isolates between host plant and gall tissues support the potential horizontal transmission of fungi into plant tissues following midge eclosion. These results suggest EF gall diversity is associated with the relationship between midges and the host species, implying EF can use A. borrichiae and host plants as vectors. Asphondylia spp. are known crop pests and inhabitants of declining ecosystems affected by climate change, while EF are dense sources of unique metabolites. Elucidating the ecology and EF diversity of multi-trophic systems can aid in understanding host-range expansion in phytophagous insects as well as potential applications biomedicine, restoration, and biocontrol.

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