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Graduation Term
Spring 2026
Degree Name
Master of Science (MS)
Department
School of Biological Sciences
Committee Chair
Thomas Hammond
Committee Member
Kevin Edwards
Committee Member
Pirmin Nietlisbach
Abstract
Meiotic drive elements, including spore killers, bias inheritance by selectively eliminating meiotic products that do not carry them. In Fusarium verticillioides, the spore killer gene SKC1 has been shown to cause spore killing and produces two protein variants through A-to-I mRNA editing: a shorter form (Skc1a) and a longer form (Skc1b). Previous work demonstrated that Skc1b causes spore killing in F. verticillioides; however, the role of Skc1a and its potential involvement in resistance to Skc1b-mediated toxicity have not been examined.
The primary objective of this study was to establish a heterologous system to study the F. verticillioides SKC1 spore killer in the model fungus Neurospora crassa and to test the functional SKC1 alleles. We constructed N. crassa strains expressing different SKC1 alleles and examined their effects. Consistent with prior observations in Fusarium, expression of Skc1b caused severe defects in ascospore development. However, expression of Skc1a had no detectable effect on ascospore viability.
We further tested the hypothesis that Skc1a functions as a resistance factor capable of suppressing Skc1b-mediated toxicity. Contrary to this hypothesis, crosses between Skc1a-expressing and Skc1b-expressing strains showed no rescue of ascospore viability, indicating that Skc1a does not confer resistance in this system.
In conclusion, these findings demonstrate that N. crassa provides a suitable system for analyzing Fusarium spore killers and supports a model in which SKC1 acts as a single-gene meiotic drive element in which Skc1b functions as a toxin and no detectable resistance function is provided by Skc1a.
Access Type
Thesis-ISU Access Only
Recommended Citation
Jazireian, Parham, "Constructing a System to Study the Fusarium verticillioides SKC1 Spore Killer in the Model Fungus Neurospora crassa" (2026). Theses and Dissertations. 2307.
https://ir.library.illinoisstate.edu/etd/2307